CUB-134: Build printers list page

Reviewed-on: #42

backend/cmd/server/main.go

@@ -12,6 +12,7 @@ import (
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/config"
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/db"
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/router"
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/sse"
 )
 
 func main() {
@@ -39,15 +40,24 @@ func main() {
 
 	slog.Info("database connected")
 
+	// Create SSE broadcaster and start it
+	sseBC := sse.NewBroadcaster(128)
+	sseBC.Start()
+	defer sseBC.Stop()
+
+	slog.Info("sse broadcaster started")
+
 	// Create router
-	r := router.New(cfg, dbPool)
+	r := router.New(cfg, dbPool, sseBC)
 
 	// Create HTTP server
+	// WriteTimeout is 0 for SSE support — the Chi middleware.Timeout(60s)
+	// handles request-level timeouts on non-SSE routes.
 	server := &http.Server{
 		Addr:         ":" + cfg.Port,
 		Handler:      r,
 		ReadTimeout:  15 * time.Second,
-		WriteTimeout: 15 * time.Second,
+		WriteTimeout: 0, // disabled for SSE long-lived connections
 		IdleTimeout:  60 * time.Second,
 	}
 

backend/internal/router/router.go

@@ -8,13 +8,14 @@ import (
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/handlers"
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/repositories"
 	"github.com/CubeCraft-Creations/Extrudex/backend/internal/services"
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/sse"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
 // New creates and configures a Chi router with all middleware and handlers mounted.
-func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
+func New(cfg *config.Config, dbPool *pgxpool.Pool, sseBC *sse.Broadcaster) chi.Router {
 	r := chi.NewRouter()
 
 	// Middleware
@@ -22,7 +23,7 @@ func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
 	r.Use(middleware.RealIP)
 	r.Use(middleware.Logger)
 	r.Use(middleware.Recoverer)
-	r.Use(middleware.Timeout(60 * time.Second))
+	// Timeout middleware is applied per-route below to exclude SSE
 
 	// CORS
 	r.Use(func(next http.Handler) http.Handler {
@@ -38,9 +39,9 @@ func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
 		})
 	})
 
-	// Health check
+	// Health check (with timeout)
 	healthHandler := handlers.NewHealthHandler(dbPool)
-	r.Get("/health", healthHandler.ServeHTTP)
+	r.With(middleware.Timeout(30 * time.Second)).Get("/health", healthHandler.ServeHTTP)
 
 	// ── Repositories ──────────────────────────────────────────────────────
 	materialRepo := repositories.NewMaterialRepository(dbPool)
@@ -61,8 +62,9 @@ func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
 	printJobHandler := handlers.NewPrintJobHandler(printJobService)
 	usageLogHandler := handlers.NewUsageLogHandler(usageLogRepo)
 
-	// ── API Routes ────────────────────────────────────────────────────────
+	// ── API Routes (with timeout) ─────────────────────────────────────────
 	r.Route("/api", func(r chi.Router) {
+		r.Use(middleware.Timeout(60 * time.Second))
 		r.Get("/materials", materialHandler.List)
 
 		r.Route("/filaments", func(r chi.Router) {
@@ -78,6 +80,10 @@ func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
 		r.Get("/printers", printerHandler.List)
 		r.Get("/print-jobs", printJobHandler.List)
 		r.Get("/usage-logs", usageLogHandler.List)
+
+		// SSE Events stream
+		sseHandler := sse.NewHandler(sseBC)
+		r.Get("/events", sseHandler.ServeHTTP)
 	})
 
 	return r

backend/internal/sse/broadcaster.go

@@ -0,0 +1,133 @@
+package sse
+
+import (
+	"log/slog"
+	"sync"
+)
+
+// client represents a single SSE subscriber — identified by its send channel.
+type client struct {
+	ch chan string
+}
+
+// Broadcaster receives Events on its input channel and fans them out to every
+// connected client. Subscribe adds a new client; Unsubscribe removes one.
+// Start must be called before the broadcaster accepts events.
+type Broadcaster struct {
+	input       chan Event
+	subscribe   chan client
+	unsubscribe chan client
+	clients     map[chan string]struct{}
+	done        chan struct{}
+	once        sync.Once
+}
+
+// NewBroadcaster creates a Broadcaster. bufSize controls the buffer depth for
+// the input channel as well as for each per-client outbound channel.
+func NewBroadcaster(bufSize int) *Broadcaster {
+	if bufSize <= 0 {
+		bufSize = 64
+	}
+	return &Broadcaster{
+		input:       make(chan Event, bufSize),
+		subscribe:   make(chan client),
+		unsubscribe: make(chan client),
+		clients:     make(map[chan string]struct{}),
+		done:        make(chan struct{}),
+	}
+}
+
+// Publish pushes an event into the broadcaster. Safe for concurrent use.
+func (b *Broadcaster) Publish(ev Event) {
+	select {
+	case b.input <- ev:
+	case <-b.done:
+		// Silently drop during shutdown.
+	}
+}
+
+// Start launches the broadcaster's fan-out loop in a goroutine.
+// It must be called before Publish is used.
+func (b *Broadcaster) Start() {
+	go b.loop()
+}
+
+// Stop terminates the fan-out loop and closes all client channels.
+// It is safe to call multiple times.
+func (b *Broadcaster) Stop() {
+	b.once.Do(func() {
+		close(b.done)
+	})
+}
+
+// Subscribe returns a new client channel that receives SSE-formatted strings.
+func (b *Broadcaster) Subscribe() chan string {
+	c := client{ch: make(chan string, 64)}
+	select {
+	case b.subscribe <- c:
+	case <-b.done:
+		// Broadcaster already stopped — return a closed chan so the handler
+		// can bail out quickly.
+		ch := make(chan string)
+		close(ch)
+		return ch
+	}
+	return c.ch
+}
+
+// Unsubscribe removes a client channel and closes it.
+func (b *Broadcaster) Unsubscribe(ch chan string) {
+	c := client{ch: ch}
+	select {
+	case b.unsubscribe <- c:
+	case <-b.done:
+		// Already shutting down — channels will be cleaned up by Stop.
+	}
+}
+
+// loop is the core fan-out goroutine.
+func (b *Broadcaster) loop() {
+	for {
+		select {
+		case ev := <-b.input:
+			sse := ev.toSSE()
+			for ch := range b.clients {
+				// Non-blocking send — slow clients are dropped.
+				select {
+				case ch <- sse:
+				default:
+					slog.Warn("sse broadcaster: dropping event for slow client", "type", ev.Type)
+				}
+			}
+
+		case c := <-b.subscribe:
+			b.clients[c.ch] = struct{}{}
+			slog.Debug("sse broadcaster: client connected", "total_clients", len(b.clients))
+
+		case c := <-b.unsubscribe:
+			if _, ok := b.clients[c.ch]; ok {
+				delete(b.clients, c.ch)
+				close(c.ch)
+				slog.Debug("sse broadcaster: client disconnected", "total_clients", len(b.clients))
+			}
+
+		case <-b.done:
+			// Drain remaining events in input before shutting down.
+			for ev := range b.input {
+				sse := ev.toSSE()
+				for ch := range b.clients {
+					select {
+					case ch <- sse:
+					default:
+					}
+				}
+			}
+			// Close all remaining client channels.
+			for ch := range b.clients {
+				close(ch)
+			}
+			b.clients = nil
+			return
+		}
+	}
+}

backend/internal/sse/events.go

@@ -0,0 +1,92 @@
+// Package sse provides Server-Sent Events infrastructure for real-time updates.
+// Includes event types, a central broadcaster, and an HTTP handler.
+package sse
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// EventType identifies the category of an SSE event.
+type EventType string
+
+const (
+	EventPrinterStatus  EventType = "printer.status"
+	EventJobStarted     EventType = "job.started"
+	EventJobCompleted   EventType = "job.completed"
+	EventFilamentLow    EventType = "filament.low"
+)
+
+// Event is a JSON-serializable SSE event pushed through the broadcaster.
+type Event struct {
+	Type      EventType       `json:"type"`
+	Payload   json.RawMessage `json:"payload"`
+	Timestamp time.Time       `json:"timestamp"`
+}
+
+// PrinterStatusPayload carries printer online/offline/printing state.
+type PrinterStatusPayload struct {
+	PrinterID   int    `json:"printer_id"`
+	PrinterName string `json:"printer_name"`
+	Status      string `json:"status"` // "online", "offline", "printing"
+}
+
+// JobStartedPayload carries initial print job info.
+type JobStartedPayload struct {
+	JobID      int    `json:"job_id"`
+	JobName    string `json:"job_name"`
+	PrinterID  int    `json:"printer_id"`
+	SpoolID    *int   `json:"spool_id,omitempty"`
+}
+
+// JobCompletedPayload carries final print job data including usage.
+type JobCompletedPayload struct {
+	JobID           int     `json:"job_id"`
+	JobName         string  `json:"job_name"`
+	PrinterID       int     `json:"printer_id"`
+	DurationSeconds *int    `json:"duration_seconds,omitempty"`
+	TotalGramsUsed  *float64 `json:"total_grams_used,omitempty"`
+	TotalCostUSD    *float64 `json:"total_cost_usd,omitempty"`
+}
+
+// FilamentLowPayload alerts that a spool is below its threshold.
+type FilamentLowPayload struct {
+	SpoolID       int    `json:"spool_id"`
+	SpoolName     string `json:"spool_name"`
+	RemainingGrams int   `json:"remaining_grams"`
+	ThresholdGrams int   `json:"threshold_grams"`
+}
+
+// NewEvent creates an Event with the current timestamp from a typed payload.
+func NewEvent(eventType EventType, payload any) (Event, error) {
+	raw, err := json.Marshal(payload)
+	if err != nil {
+		return Event{}, err
+	}
+	return Event{
+		Type:      eventType,
+		Payload:   raw,
+		Timestamp: time.Now().UTC(),
+	}, nil
+}
+
+// MustEvent creates an Event and panics on marshal failure (for use with
+// known-good payloads in tests and internal wiring).
+func MustEvent(eventType EventType, payload any) Event {
+	ev, err := NewEvent(eventType, payload)
+	if err != nil {
+		panic("sse.MustEvent: failed to marshal payload: " + err.Error())
+	}
+	return ev
+}
+
+// toSSE formats this Event as a standard SSE message string ready to be
+// written to a response writer. The format is:
+//
+//	event: <type>
+//	data: <json>
+//
+func (e Event) toSSE() string {
+	data, _ := json.Marshal(e)
+	return "event: " + string(e.Type) + "\n" + "data: " + string(data) + "\n\n"
+}

backend/internal/sse/handler.go

@@ -0,0 +1,59 @@
+package sse
+
+import (
+	"net/http"
+)
+
+// Handler is the HTTP handler for the GET /api/events SSE stream.
+// It registers a client with the broadcaster, streams events as they arrive,
+// and unregisters on disconnect.
+type Handler struct {
+	bc *Broadcaster
+}
+
+// NewHandler creates a Handler backed by the given Broadcaster.
+func NewHandler(bc *Broadcaster) *Handler {
+	return &Handler{bc: bc}
+}
+
+// ServeHTTP implements the SSE streaming endpoint.
+// Flusher is required; clients that do not support flushing receive a 501.
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	flusher, ok := w.(http.Flusher)
+	if !ok {
+		http.Error(w, "streaming not supported", http.StatusNotImplemented)
+		return
+	}
+
+	// SSE-specific headers
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Connection", "keep-alive")
+	w.Header().Set("X-Accel-Buffering", "no") // Disable nginx buffering
+
+	// Write headers immediately
+	flusher.Flush()
+
+	// Subscribe to the broadcaster
+	ch := h.bc.Subscribe()
+	defer h.bc.Unsubscribe(ch)
+
+	// Use request context for cancellation when the client disconnects.
+	ctx := r.Context()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case msg, ok := <-ch:
+			if !ok {
+				return
+			}
+			_, err := w.Write([]byte(msg))
+			if err != nil {
+				return
+			}
+			flusher.Flush()
+		}
+	}
+}

docs/CONTEXT.md

@@ -0,0 +1,214 @@
+# Extrudex — Project Context
+
+> **Last updated:** 2026-05-21
+> **Repo:** `CubeCraft-Creations/Extrudex` | **Host:** `code.cubecraftcreations.com`
+> **Local clone:** `/mnt/ai-storage/projects/Extrudex` | **Default branch:** `dev`
+> **Discord:** `DISCORD_DEV_EXTRUDEX_CHANNEL_ID`
+> **Linear Epic:** [CUB-110](https://linear.app/cubecraft-creations/issue/CUB-110)
+
+---
+
+## Overview
+
+Custom filament inventory and print tracking system for CubeCraft Creations. Tracks spool consumption, material costs, and per-print COGS across a fleet of 6 FDM printers (5 Bambu Lab + 1 Elegoo Centauri Carbon) + resin printers. Kiosk interface on Raspberry Pi 5 with USB barcode scanner.
+
+**Active refactor in progress:** .NET → Go + React (CUB-110 epic).
+
+## Tech Stack
+
+| Layer | Technology | Notes |
+|-------|-----------|-------|
+| Backend (legacy) | ASP.NET Core 9 + EF Core | Being replaced by Go |
+| Backend (new) | Go 1.24+ | Chi router, pgx (PostgreSQL), gorilla/websocket, paho.mqtt.golang |
+| Frontend (legacy) | Angular 17+ | Being replaced by React |
+| Frontend (new) | React 18 + TypeScript + Tailwind CSS | Vite |
+| Database | PostgreSQL 16+ | snake_case naming |
+| Real-time | SSE (Server-Sent Events) | Replaces SignalR |
+| Printer integrations | Moonraker REST + WebSocket, MQTT TLS | Elegoo/Klipper + Bambu Lab |
+| CI/CD | Gitea Actions | `.gitea/workflows/dev.yml` |
+| Deployment | Docker/Compose, Pi 5 kiosk | |
+
+## Key Design Decisions
+
+1. **Custom system over Spoolman** — Full control over data model and integrations
+2. **MaterialFinish required** on every spool; default is "Basic"
+3. **MaterialModifier is optional**
+4. **Grams derived from:** `mm_extruded × filament_cross_section_area × material_density`
+5. **Push over poll** — SSE + MQTT preferred; Moonraker polling is fallback
+6. **Snake_case** for all PostgreSQL identifiers
+
+## Project Structure
+
+```
+Extrudex/
+├── backend/                         # Original .NET backend (being replaced)
+│   ├── API/Controllers/             # Filaments, Spools, PrintJobs, Printers, Materials, QR, UsageLogs, Cost
+│   ├── API/DTOs/                    # DTOs per domain
+│   ├── API/Validators/              # FluentValidation rules
+│   ├── API/Hubs/                    # SignalR PrinterHub
+│   ├── API/Jobs/                    # Background sync jobs
+│   ├── Domain/Entities/             # EF Core entities (Printer, Spool, PrintJob, MaterialBase, etc.)
+│   ├── Domain/Enums/                # ConnectionType, DataSource, JobStatus, PrinterStatus, QrResourceType
+│   ├── Domain/Interfaces/           # Service interfaces
+│   ├── Infrastructure/Data/         # EF DbContext, Configurations, Migrations, SeedData
+│   ├── Infrastructure/Services/     # MoonrakerClient, CostPerPrint, UsageLog, FilamentUsage, QR
+│   └── Program.cs                  # ASP.NET entry point
+├── cmd/server/main.go              # Go entrypoint (new), worker discovery, graceful shutdown
+├── internal/                       # Go backend (new)
+│   ├── config/config.go            # Env vars
+│   ├── db/db.go                    # PostgreSQL connection pool (pgx)
+│   ├── models/models.go            # Go domain structs
+│   ├── router/router.go            # Chi HTTP routes
+│   ├── sse/broadcaster.go          # SSE broadcaster
+│   ├── sse/events.go               # SSE event types
+│   ├── sse/handler.go              # SSE HTTP handler
+│   ├── handlers/                   # API handlers (filament, health, material, print_job, printer, usage_log)
+│   ├── repositories/               # DB access layer
+│   └── services/                   # Business logic + validation
+├── migrations/                     # Go-migrate SQL migrations
+│   ├── 000001_initial_schema.up.sql
+│   ├── 000001_initial_schema.down.sql
+│   ├── 000002_seed_data.up.sql
+│   └── 000002_seed_data.down.sql
+├── frontend/                       # React frontend (new)
+│   ├── src/
+│   │   ├── App.tsx
+│   │   ├── main.tsx
+│   │   ├── components/             # ColorSwatch, LoadingSpinner, RecentPrints, SummaryCard
+│   │   ├── pages/
+│   │   │   ├── Dashboard.tsx       # Main dashboard with summary cards + recent prints
+│   │   │   └── InventoryPage.tsx   # Filament inventory list (table + filters)
+│   │   ├── services/
+│   │   │   ├── api.ts              # Axios client
+│   │   │   └── filamentService.ts
+│   │   ├── stores/                 # State stores (WIP)
+│   │   ├── types/
+│   │   │   ├── filament.ts
+│   │   │   └── index.ts
+│   │   └── hooks/
+│   ├── Dockerfile + nginx.conf
+│   └── vite.config.ts, tailwind.config.js
+├── design/                         # UX/design specs + mockup images
+│   ├── homepage-spec.md
+│   ├── 01-filament-inventory-list.md
+│   ├── 02-spool-detail-view.md
+│   ├── 03-smart-intake-workflow.md
+│   ├── smart-intake-identify-spec.md
+│   └── *.jpg / *.png               # Mockup images (kiosk + mobile)
+├── docker-compose.dev.yml
+└── deploy.sh
+```
+
+## Database Schema (PostgreSQL — .NET EF Core Migrations)
+
+Core entities managed by EF Core with full configurations:
+- **Printers** — id, name, type (BambuLab/Moonraker), connection_type, status, ip_address, mac_address, ams_count
+- **AmsUnit / AmsSlot** — Bambu Lab AMS tray tracking
+- **Spools** — filament inventory with material, color, weight, location, QR support
+- **MaterialBase / MaterialFinish / MaterialModifier** — material taxonomy
+- **PrintJobs** — job tracking with status, cost, filament consumption
+- **UsageLogs** — per-printer filament consumption records
+- **FilamentUsage** — aggregated per-spool consumption tracking
+- **FilamentUsageSyncJob** — background Moonraker polling
+- **MoonrakerPrinterSyncJob** — background printer status sync
+
+## API Endpoints (.NET)
+
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| GET | /api/filaments | List filaments (paginated, filterable) |
+| POST | /api/filaments | Create filament |
+| GET | /api/filaments/{id} | Get filament detail |
+| PUT | /api/filaments/{id} | Update filament |
+| DELETE | /api/filaments/{id} | Delete filament |
+| GET | /api/spools | List spools |
+| POST | /api/spools | Create spool |
+| GET | /api/spools/{id} | Get spool detail |
+| PUT | /api/spools/{id} | Update spool |
+| DELETE | /api/spools/{id} | Delete spool |
+| GET | /api/print-jobs | List print jobs |
+| POST | /api/print-jobs | Create print job |
+| GET | /api/print-jobs/{id} | Get print job detail |
+| GET | /api/printers | List printers |
+| POST | /api/printers | Register printer |
+| GET | /api/printers/{id} | Get printer detail |
+| GET | /api/printers/{id}/costs | Per-print cost summary |
+| GET | /api/printers/{id}/usage | Filament usage history |
+| GET | /api/materials/bases | List material bases |
+| POST | /api/materials/bases | Create material base |
+| GET | /api/materials/finishes | List material finishes |
+| POST | /api/materials/finishes | Create material finish |
+| GET | /api/materials/modifiers | List material modifiers |
+| POST | /api/materials/modifiers | Create modifier |
+| GET | /api/materials/lookups | Unified material lookup |
+| GET | /api/qr/resolve/{code} | QR code resolve |
+| GET | /api/usage-logs | List usage logs |
+| POST | /api/usage-logs | Create usage log |
+
+## CUB-110 Epic Progress (Go + React Rewrite)
+
+| Sub-task | Title | Status | Agent |
+|----------|-------|--------|-------|
+| CUB-111 | Design PostgreSQL schema | Done | Hex |
+| CUB-112 | Scaffold Go backend | Done | Dex |
+| CUB-113 | Core CRUD API endpoints | Done | Dex |
+| CUB-116 | Scaffold React frontend | In Review | Rex |
+| CUB-117 | Moonraker + MQTT integrations | In Progress | Dex |
+| CUB-118 | (deprecated → CUB-135 + CUB-136) | — | — |
+| CUB-130 | Add/Edit Filament form | In Review | Rex |
+| CUB-131 | Filament Detail page | In Review | Rex |
+| CUB-132 | Filament Inventory list | Done | Rex |
+| CUB-133 | Dashboard summary cards | In Review | Rex |
+| CUB-134 | Printers list page | Todo | Rex |
+| CUB-135 | Subscribe to SSE in React | In Review | Rex |
+| CUB-136 | Add SSE endpoint in Go | In Review | Dex |
+| CUB-128 | Settings page | Todo | — |
+| CUB-129 | Print Jobs list page | Todo | — |
+| CUB-114 | Pi 5 kiosk deployment | Todo | — |
+
+## Active Branches
+
+| Branch | Agent | Issue | Status |
+|--------|-------|-------|--------|
+| `agent/dex/CUB-117-moonraker-mqtt-go` | Dex | CUB-117 | Local commit ready |
+| `agent/dex/CUB-136-sse-endpoint` | Dex | CUB-136 | PR open |
+| `agent/rex/CUB-130-filament-form` | Rex | CUB-130 | PR open |
+| `agent/rex/CUB-131-filament-detail` | Rex | CUB-131 | PR open |
+| `agent/rex/CUB-133-dashboard-cards` | Rex | CUB-133 | PR open |
+| `agent/rex/CUB-135-sse-subscribe` | Rex | CUB-135 | PR open |
+
+## Known Limitations
+
+- Go rewrite is in progress — backend `internal/` is new Go code, but legacy .NET code still serves endpoints
+- Kiosk deployment not finalized (CUB-114)
+- Smart intake workflow is designed but not implemented
+- MQTT Bambu Lab integration is partially complete (CUB-117)
+
+## Default Agent Assignments
+
+| Area | Agent | Notes |
+|------|-------|-------|
+| Backend (Go API, Moonraker, MQTT) | Dex | gitea-dex MCP |
+| Database (PostgreSQL schema, migrations) | Hex | gitea-hex MCP |
+| Frontend (React, Tailwind) | Rex | gitea-rex MCP |
+| Design (wireframes, UX) | Sketch | |
+
+## Getting Started
+
+```bash
+cd /mnt/ai-storage/projects/Extrudex
+git checkout dev
+git pull origin dev
+
+# Legacy .NET backend
+cd backend && dotnet run
+
+# New Go backend
+go run cmd/server/main.go
+
+# React frontend
+cd frontend && npm install && npm run dev
+
+# Docker
+docker compose -f docker-compose.dev.yml up --build
+```

frontend/src/App.tsx

@@ -1,28 +1,36 @@
-import { useState, useEffect } from 'react'
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { BrowserRouter, Routes, Route } from 'react-router-dom'
+import Dashboard from './pages/Dashboard'
+import InventoryPage from './pages/InventoryPage'
+import PrintersPage from './pages/PrintersPage'
 
-function App() {
-  const [health, setHealth] = useState<any>(null)
-
-  useEffect(() => {
-    fetch('/api/health')
-      .then(r => r.json())
-      .then(setHealth)
-      .catch(console.error)
-  }, [])
+const queryClient = new QueryClient()
 
+export default function App() {
   return (
-    <div className="min-h-screen flex items-center justify-center">
-      <div className="p-6 rounded-lg bg-slate-800 shadow-xl max-w-md w-full">
-        <h1 className="text-2xl font-bold mb-4 text-emerald-400">Extrudex</h1>
-        <p className="text-slate-300 mb-4">React frontend scaffold</p>
-        {health && (
-          <pre className="text-xs bg-slate-900 p-3 rounded overflow-auto">
-            {JSON.stringify(health, null, 2)}
-          </pre>
-        )}
-      </div>
+    <QueryClientProvider client={queryClient}>
+      <BrowserRouter>
+        <div className="min-h-screen bg-slate-900 text-slate-50">
+          <header className="bg-slate-800 border-b border-slate-700 px-4 py-3 flex items-center gap-4 sticky top-0 z-20">
+            <a href="/" className="flex items-center gap-3 no-underline">
+              <div className="w-8 h-8 rounded bg-emerald-500 flex items-center justify-center text-slate-900 font-bold text-lg">E</div>
+              <h1 className="text-lg font-semibold text-slate-50">Extrudex</h1>
+            </a>
+            <nav className="flex items-center gap-1 ml-2">
+              <a href="/" className="px-3 py-1.5 rounded-md text-sm text-slate-300 hover:text-slate-100 hover:bg-slate-700 transition-colors">Dashboard</a>
+              <a href="/inventory" className="px-3 py-1.5 rounded-md text-sm text-slate-300 hover:text-slate-100 hover:bg-slate-700 transition-colors">Inventory</a>
+              <a href="/printers" className="px-3 py-1.5 rounded-md text-sm text-slate-300 hover:text-slate-100 hover:bg-slate-700 transition-colors">Printers</a>
+            </nav>
+          </header>
+          <main className="p-4">
+            <Routes>
+              <Route path="/" element={<Dashboard />} />
+              <Route path="/inventory" element={<InventoryPage />} />
+              <Route path="/printers" element={<PrintersPage />} />
+            </Routes>
+          </main>
         </div>
+      </BrowserRouter>
+    </QueryClientProvider>
   )
 }
-
-export default App

frontend/src/components/ColorSwatch.tsx

@@ -0,0 +1,18 @@
+interface ColorSwatchProps {
+  colorHex: string
+  size?: number
+}
+
+export default function ColorSwatch({ colorHex, size = 24 }: ColorSwatchProps) {
+  return (
+    <div
+      className="rounded-full border border-slate-600 shadow-sm inline-block"
+      style={{
+        backgroundColor: colorHex.startsWith('#') ? colorHex : `#${colorHex}`,
+        width: size,
+        height: size,
+      }}
+      title={colorHex}
+    />
+  )
+}

frontend/src/components/LoadingSpinner.tsx

@@ -0,0 +1,8 @@
+export default function LoadingSpinner() {
+  return (
+    <div className="flex flex-col items-center gap-3">
+      <div className="w-10 h-10 border-4 border-emerald-500/30 border-t-emerald-400 rounded-full animate-spin" />
+      <p className="text-slate-400 text-sm">Loading dashboard…</p>
+    </div>
+  )
+}

frontend/src/components/RecentPrints.tsx

@@ -0,0 +1,76 @@
+import type { PrintJob } from '../types'
+import { Clock, FileText } from 'lucide-react'
+
+interface RecentPrintsProps {
+  jobs: PrintJob[]
+}
+
+export default function RecentPrints({ jobs }: RecentPrintsProps) {
+  if (jobs.length === 0) {
+    return (
+      <div className="rounded-xl border border-slate-700 bg-slate-800 p-6 text-center text-slate-400">
+        <FileText size={32} className="mx-auto mb-3 text-slate-500" />
+        <p>No recent print jobs</p>
+      </div>
+    )
+  }
+
+  const statusColor = (status: string) => {
+    switch (status.toLowerCase()) {
+      case 'completed': return 'text-emerald-400 bg-emerald-500/10'
+      case 'in_progress': return 'text-sky-400 bg-sky-500/10'
+      case 'failed': return 'text-red-400 bg-red-500/10'
+      default: return 'text-slate-400 bg-slate-500/10'
+    }
+  }
+
+  return (
+    <div className="rounded-xl border border-slate-700 bg-slate-800 overflow-hidden">
+      <div className="overflow-x-auto">
+        <table className="w-full text-left">
+          <thead>
+            <tr className="border-b border-slate-700">
+              <th className="px-4 py-3 text-sm font-medium text-slate-400">Name</th>
+              <th className="px-4 py-3 text-sm font-medium text-slate-400">Status</th>
+              <th className="px-4 py-3 text-sm font-medium text-slate-400">Duration</th>
+              <th className="px-4 py-3 text-sm font-medium text-slate-400">Filament</th>
+              <th className="px-4 py-3 text-sm font-medium text-slate-400">Cost</th>
+            </tr>
+          </thead>
+          <tbody>
+            {jobs.map((job) => (
+              <tr key={job.id} className="border-b border-slate-700/50 last:border-0 hover:bg-slate-700/30 transition-colors">
+                <td className="px-4 py-3 text-sm text-slate-100 font-medium">{job.name}</td>
+                <td className="px-4 py-3">
+                  <span className={`inline-flex items-center gap-1 px-2 py-1 rounded-full text-xs font-medium ${statusColor(job.status)}`}>
+                    {job.status}
+                  </span>
+                </td>
+                <td className="px-4 py-3 text-sm text-slate-300">
+                  <div className="flex items-center gap-1">
+                    <Clock size={14} />
+                    {formatDuration(job.duration_seconds)}
+                  </div>
+                </td>
+                <td className="px-4 py-3 text-sm text-slate-300">
+                  {job.filament_used_grams?.toFixed(1) ?? '-'} g
+                </td>
+                <td className="px-4 py-3 text-sm text-slate-300">
+                  ${job.cost_usd?.toFixed(2) ?? '-'}
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+    </div>
+  )
+}
+
+function formatDuration(seconds: number): string {
+  if (!seconds) return '-'
+  const hrs = Math.floor(seconds / 3600)
+  const mins = Math.floor((seconds % 3600) / 60)
+  if (hrs > 0) return `${hrs}h ${mins}m`
+  return `${mins}m`
+}

frontend/src/components/SummaryCard.tsx

@@ -0,0 +1,31 @@
+import type { LucideIcon } from 'lucide-react'
+
+interface SummaryCardProps {
+  title: string
+  value: string | number
+  icon: LucideIcon
+  color: 'emerald' | 'amber' | 'sky' | 'violet'
+}
+
+const colorMap = {
+  emerald: { bg: 'bg-emerald-500/10', border: 'border-emerald-500/20', text: 'text-emerald-400', icon: 'text-emerald-400' },
+  amber:   { bg: 'bg-amber-500/10',  border: 'border-amber-500/20',  text: 'text-amber-400',  icon: 'text-amber-400' },
+  sky:     { bg: 'bg-sky-500/10',    border: 'border-sky-500/20',    text: 'text-sky-400',    icon: 'text-sky-400' },
+  violet:  { bg: 'bg-violet-500/10', border: 'border-violet-500/20', text: 'text-violet-400', icon: 'text-violet-400' },
+}
+
+export default function SummaryCard({ title, value, icon: Icon, color }: SummaryCardProps) {
+  const c = colorMap[color]
+
+  return (
+    <div className={`rounded-xl border ${c.border} ${c.bg} p-5 flex items-start justify-between`}>
+      <div>
+        <p className="text-sm font-medium text-slate-400 mb-1">{title}</p>
+        <p className={`text-3xl font-bold ${c.text}`}>{value}</p>
+      </div>
+      <div className={`p-2 rounded-lg ${c.bg}`}>
+        <Icon size={24} className={c.icon} />
+      </div>
+    </div>
+  )
+}

frontend/src/main.tsx

@@ -1,10 +1,25 @@
 import { StrictMode } from 'react'
 import { createRoot } from 'react-dom/client'
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { BrowserRouter } from 'react-router-dom'
 import './index.css'
 import App from './App'
 
+const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      staleTime: 30_000,
+      refetchOnWindowFocus: false,
+    },
+  },
+})
+
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
+    <QueryClientProvider client={queryClient}>
+      <BrowserRouter>
         <App />
+      </BrowserRouter>
+    </QueryClientProvider>
   </StrictMode>,
 )

frontend/src/pages/Dashboard.tsx

@@ -0,0 +1,139 @@
+import { useQuery } from '@tanstack/react-query'
+import { getFilaments, getPrintJobs } from '../services/api'
+import SummaryCard from '../components/SummaryCard'
+import RecentPrints from '../components/RecentPrints'
+import LoadingSpinner from '../components/LoadingSpinner'
+import { Package, AlertTriangle, Printer, DollarSign, Plus, List } from 'lucide-react'
+
+export default function Dashboard() {
+  const {
+    data: filamentData,
+    isLoading: filamentLoading,
+    error: filamentError,
+  } = useQuery({
+    queryKey: ['filaments', 'count'],
+    queryFn: () => getFilaments({ limit: 1 }),
+  })
+
+  const {
+    data: lowStockData,
+    isLoading: lowStockLoading,
+    error: lowStockError,
+  } = useQuery({
+    queryKey: ['filaments', 'lowStock'],
+    queryFn: () => getFilaments({ low_stock: true, limit: 1 }),
+  })
+
+  const {
+    data: recentPrints,
+    isLoading: printsLoading,
+    error: printsError,
+  } = useQuery({
+    queryKey: ['printJobs', 'recent'],
+    queryFn: () => getPrintJobs({ limit: 5 }),
+  })
+
+  const {
+    data: allPrints,
+    isLoading: costLoading,
+    error: costError,
+  } = useQuery({
+    queryKey: ['printJobs', 'all'],
+    queryFn: () => getPrintJobs({ limit: 1000 }),
+  })
+
+  const totalSpools = filamentData?.total ?? 0
+  const lowStockCount = lowStockData?.total ?? 0
+  const recentPrintJobs = recentPrints?.data ?? []
+
+  // Calculate cost this month from all print jobs
+  const now = new Date()
+  const currentMonth = now.getMonth()
+  const currentYear = now.getFullYear()
+  const monthlyCost =
+    allPrints?.data
+      .filter((job) => {
+        const d = new Date(job.started_at)
+        return d.getMonth() === currentMonth && d.getFullYear() === currentYear
+      })
+      .reduce((sum, job) => sum + (job.cost_usd ?? 0), 0) ?? 0
+
+  const isLoading = filamentLoading || lowStockLoading || printsLoading || costLoading
+  const error = filamentError || lowStockError || printsError || costError
+
+  if (isLoading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center bg-slate-900">
+        <LoadingSpinner />
+      </div>
+    )
+  }
+
+  if (error) {
+    return (
+      <div className="min-h-screen flex items-center justify-center bg-slate-900">
+        <div className="p-6 rounded-lg bg-red-900/30 border border-red-500 text-red-200 max-w-md">
+          <h2 className="text-xl font-bold mb-2">Error</h2>
+          <p className="text-sm">{(error as Error).message || 'Failed to load dashboard data.'}</p>
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="min-h-screen bg-slate-900 p-4 md:p-8">
+      <div className="max-w-6xl mx-auto">
+        <header className="mb-8">
+          <h1 className="text-3xl font-bold text-emerald-400 mb-2">Dashboard</h1>
+          <p className="text-slate-400">Overview of your Extrudex inventory and prints</p>
+        </header>
+
+        {/* Summary Cards Grid */}
+        <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4 mb-8">
+          <SummaryCard
+            title="Total Spools"
+            value={totalSpools}
+            icon={Package}
+            color="emerald"
+          />
+          <SummaryCard
+            title="Low Stock"
+            value={lowStockCount}
+            icon={AlertTriangle}
+            color={lowStockCount > 0 ? 'amber' : 'emerald'}
+          />
+          <SummaryCard
+            title="Recent Prints"
+            value={recentPrintJobs.length}
+            icon={Printer}
+            color="sky"
+          />
+          <SummaryCard
+            title="Cost This Month"
+            value={`$${monthlyCost.toFixed(2)}`}
+            icon={DollarSign}
+            color="violet"
+          />
+        </div>
+
+        {/* Quick Actions */}
+        <div className="flex flex-wrap gap-3 mb-8">
+          <button className="flex items-center gap-2 px-4 py-2 rounded-lg bg-emerald-600 hover:bg-emerald-500 text-white font-medium transition-colors active:scale-95 touch-manipulation">
+            <Plus size={18} />
+            Add Spool
+          </button>
+          <button className="flex items-center gap-2 px-4 py-2 rounded-lg bg-slate-700 hover:bg-slate-600 text-slate-100 font-medium transition-colors active:scale-95 touch-manipulation">
+            <List size={18} />
+            View Inventory
+          </button>
+        </div>
+
+        {/* Recent Prints Section */}
+        <section>
+          <h2 className="text-xl font-semibold text-slate-100 mb-4">Recent Prints</h2>
+          <RecentPrints jobs={recentPrintJobs} />
+        </section>
+      </div>
+    </div>
+  )
+}

frontend/src/pages/InventoryPage.tsx

@@ -0,0 +1,339 @@
+import { useState, useMemo } from 'react'
+import { useQuery } from '@tanstack/react-query'
+import { Search, Filter, ChevronLeft, ChevronRight, Trash2, Pencil, Plus, AlertTriangle } from 'lucide-react'
+import ColorSwatch from '../components/ColorSwatch'
+import { fetchFilaments, deleteFilament } from '../services/filamentService'
+import type { FilamentSpool, FilamentFilter } from '../types/filament'
+
+const PAGE_SIZE = 20
+
+type SortField = 'name' | 'remaining_grams' | 'cost_usd'
+type SortDir = 'asc' | 'desc'
+
+export default function InventoryPage() {
+  const [search, setSearch] = useState('')
+  const [material, setMaterial] = useState('')
+  const [finish, setFinish] = useState('')
+  const [lowStockOnly, setLowStockOnly] = useState(false)
+  const [sortBy, setSortBy] = useState<SortField>('name')
+  const [sortDir, setSortDir] = useState<SortDir>('asc')
+  const [page, setPage] = useState(0)
+  const [deleteId, setDeleteId] = useState<number | null>(null)
+
+  const filter: FilamentFilter = useMemo(() => ({
+    material: material || undefined,
+    finish: finish || undefined,
+    low_stock: lowStockOnly,
+    sort_by: sortBy,
+    sort_dir: sortDir,
+    limit: PAGE_SIZE,
+    offset: page * PAGE_SIZE,
+  }), [material, finish, lowStockOnly, sortBy, sortDir, page])
+
+  const { data, isLoading, error, refetch } = useQuery({
+    queryKey: ['filaments', filter],
+    queryFn: () => fetchFilaments(filter),
+  })
+
+  const filaments = data?.data ?? []
+  const total = data?.total ?? 0
+  const totalPages = Math.max(1, Math.ceil(total / PAGE_SIZE))
+
+  // Client-side search filter (name/barcode) since backend may not support it yet.
+  const filtered = useMemo(() => {
+    if (!search.trim()) return filaments
+    const q = search.toLowerCase()
+    return filaments.filter(
+      (f: FilamentSpool) =>
+        f.name.toLowerCase().includes(q) ||
+        (f.barcode && f.barcode.toLowerCase().includes(q))
+    )
+  }, [filaments, search])
+
+  const handleSort = (field: SortField) => {
+    if (sortBy === field) {
+      setSortDir(prev => (prev === 'asc' ? 'desc' : 'asc'))
+    } else {
+      setSortBy(field)
+      setSortDir('asc')
+    }
+    setPage(0)
+  }
+
+  const handleDelete = async (id: number) => {
+    await deleteFilament(id)
+    setDeleteId(null)
+    refetch()
+  }
+
+  const SortIndicator = ({ field }: { field: SortField }) => {
+    if (sortBy !== field) return <span className="text-slate-600 ml-1">↕</span>
+    return <span className="text-emerald-400 ml-1">{sortDir === 'asc' ? '↑' : '↓'}</span>
+  }
+
+  return (
+    <div className="space-y-4">
+      {/* Header */}
+      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-3">
+        <div>
+          <h2 className="text-xl font-bold text-slate-100">Filament Inventory</h2>
+          <p className="text-sm text-slate-400">{total} spool(s) total</p>
+        </div>
+        <button className="inline-flex items-center gap-2 rounded-lg bg-emerald-600 px-4 py-2 text-sm font-semibold text-white hover:bg-emerald-500 active:bg-emerald-700 transition-colors">
+          <Plus size={16} /> Add Spool
+        </button>
+      </div>
+
+      {/* Filters */}
+      <div className="flex flex-col lg:flex-row gap-3">
+        {/* Search */}
+        <div className="relative flex-1">
+          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-slate-400" />
+          <input
+            type="text"
+            placeholder="Search by name or barcode…"
+            value={search}
+            onChange={e => { setSearch(e.target.value); setPage(0) }}
+            className="w-full rounded-lg bg-slate-800 border border-slate-700 pl-9 pr-3 py-2 text-sm text-slate-100 placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:border-emerald-500"
+          />
+        </div>
+
+        {/* Material filter */}
+        <select
+          value={material}
+          onChange={e => { setMaterial(e.target.value); setPage(0) }}
+          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 focus:outline-none focus:ring-2 focus:ring-emerald-500"
+        >
+          <option value="">All Materials</option>
+          <option value="PLA">PLA</option>
+          <option value="PETG">PETG</option>
+          <option value="ABS">ABS</option>
+          <option value="TPU">TPU</option>
+          <option value="ASA">ASA</option>
+          <option value="Nylon">Nylon</option>
+          <option value="PC">PC</option>
+        </select>
+
+        {/* Finish filter */}
+        <select
+          value={finish}
+          onChange={e => { setFinish(e.target.value); setPage(0) }}
+          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 focus:outline-none focus:ring-2 focus:ring-emerald-500"
+        >
+          <option value="">All Finishes</option>
+          <option value="Basic">Basic</option>
+          <option value="Silk">Silk</option>
+          <option value="Matte">Matte</option>
+          <option value="Glossy">Glossy</option>
+          <option value="Wood">Wood</option>
+          <option value="Marble">Marble</option>
+        </select>
+
+        {/* Low stock toggle */}
+        <label className="inline-flex items-center gap-2 rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 cursor-pointer select-none hover:bg-slate-750">
+          <Filter size={14} className="text-amber-400" />
+          <input
+            type="checkbox"
+            checked={lowStockOnly}
+            onChange={e => { setLowStockOnly(e.target.checked); setPage(0) }}
+            className="accent-amber-500"
+          />
+          Low Stock Only
+        </label>
+      </div>
+
+      {/* Loading / Error */}
+      {isLoading && (
+        <div className="text-center py-12 text-slate-400">Loading spools…</div>
+      )}
+      {error && (
+        <div className="text-center py-12 text-red-400">
+          Failed to load inventory.
+          <button onClick={() => refetch()} className="ml-2 underline hover:text-red-300">Retry</button>
+        </div>
+      )}
+
+      {/* Desktop Table */}
+      {!isLoading && !error && (
+        <>
+          <div className="hidden md:block overflow-x-auto rounded-lg border border-slate-700">
+            <table className="w-full text-sm">
+              <thead className="bg-slate-800 text-slate-300">
+                <tr>
+                  <th className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('name')}>
+                    Name <SortIndicator field="name" />
+                  </th>
+                  <th className="px-4 py-3 text-left font-semibold">Material</th>
+                  <th className="px-4 py-3 text-left font-semibold">Finish</th>
+                  <th className="px-4 py-3 text-left font-semibold">Color</th>
+                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('remaining_grams')}>
+                    Remaining <SortIndicator field="remaining_grams" />
+                  </th>
+                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('cost_usd')}>
+                    Cost <SortIndicator field="cost_usd" />
+                  </th>
+                  <th className="px-4 py-3 text-center font-semibold">Status</th>
+                  <th className="px-4 py-3 text-right font-semibold">Actions</th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-slate-700">
+                {filtered.length === 0 && (
+                  <tr>
+                    <td colSpan={8} className="px-4 py-8 text-center text-slate-500">No spools found.</td>
+                  </tr>
+                )}
+                {filtered.map((spool: FilamentSpool) => {
+                  const isLow = spool.remaining_grams <= spool.low_stock_threshold_grams
+                  return (
+                    <tr key={spool.id} className={`${isLow ? 'bg-red-900/20' : 'bg-slate-800/50'} hover:bg-slate-700/50 transition-colors`}>
+                      <td className="px-4 py-3 font-medium text-slate-100">{spool.name}</td>
+                      <td className="px-4 py-3 text-slate-300">{spool.material_base?.name ?? '—'}</td>
+                      <td className="px-4 py-3 text-slate-300">{spool.material_finish?.name ?? '—'}</td>
+                      <td className="px-4 py-3">
+                        <div className="flex items-center gap-2">
+                          <ColorSwatch colorHex={spool.color_hex} size={20} />
+                          <span className="text-xs text-slate-400 uppercase">{spool.color_hex}</span>
+                        </div>
+                      </td>
+                      <td className="px-4 py-3 text-right tabular-nums text-slate-200">{spool.remaining_grams.toLocaleString()} g</td>
+                      <td className="px-4 py-3 text-right tabular-nums text-slate-300">{spool.cost_usd != null ? `$${spool.cost_usd.toFixed(2)}` : '—'}</td>
+                      <td className="px-4 py-3 text-center">
+                        {isLow ? (
+                          <span className="inline-flex items-center gap-1 rounded-full bg-red-900/50 border border-red-700 px-2 py-0.5 text-xs font-medium text-red-300">
+                            <AlertTriangle size={12} /> Low
+                          </span>
+                        ) : (
+                          <span className="inline-flex items-center rounded-full bg-emerald-900/30 border border-emerald-700 px-2 py-0.5 text-xs font-medium text-emerald-300">OK</span>
+                        )}
+                      </td>
+                      <td className="px-4 py-3 text-right">
+                        <div className="flex items-center justify-end gap-2">
+                          <button className="p-1.5 rounded hover:bg-slate-600 text-slate-400 hover:text-blue-400 transition-colors" title="Edit">
+                            <Pencil size={14} />
+                          </button>
+                          <button
+                            onClick={() => setDeleteId(spool.id)}
+                            className="p-1.5 rounded hover:bg-slate-600 text-slate-400 hover:text-red-400 transition-colors"
+                            title="Delete"
+                          >
+                            <Trash2 size={14} />
+                          </button>
+                        </div>
+                      </td>
+                    </tr>
+                  )
+                })}
+              </tbody>
+            </table>
+          </div>
+
+          {/* Mobile Cards */}
+          <div className="md:hidden space-y-3">
+            {filtered.length === 0 && (
+              <div className="text-center py-12 text-slate-500">No spools found.</div>
+            )}
+            {filtered.map((spool: FilamentSpool) => {
+              const isLow = spool.remaining_grams <= spool.low_stock_threshold_grams
+              return (
+                <div key={spool.id} className={`rounded-lg border ${isLow ? 'border-red-700 bg-red-900/10' : 'border-slate-700 bg-slate-800'} p-4 space-y-2`}>
+                  <div className="flex items-start justify-between">
+                    <div>
+                      <div className="font-semibold text-slate-100">{spool.name}</div>
+                      <div className="text-xs text-slate-400 mt-0.5">{spool.material_base?.name ?? '—'} · {spool.material_finish?.name ?? '—'}</div>
+                    </div>
+                    {isLow ? (
+                      <span className="inline-flex items-center gap-1 rounded-full bg-red-900/50 border border-red-700 px-2 py-0.5 text-xs font-medium text-red-300">
+                        <AlertTriangle size={12} /> Low
+                      </span>
+                    ) : (
+                      <span className="inline-flex items-center rounded-full bg-emerald-900/30 border border-emerald-700 px-2 py-0.5 text-xs font-medium text-emerald-300">OK</span>
+                    )}
+                  </div>
+
+                  <div className="flex items-center gap-3 text-sm">
+                    <div className="flex items-center gap-2">
+                      <ColorSwatch colorHex={spool.color_hex} size={20} />
+                      <span className="text-slate-400 uppercase text-xs">{spool.color_hex}</span>
+                    </div>
+                  </div>
+
+                  <div className="flex items-center justify-between text-sm">
+                    <span className="text-slate-400">Remaining: <span className="text-slate-200 font-medium tabular-nums">{spool.remaining_grams.toLocaleString()} g</span></span>
+                    <span className="text-slate-400">{spool.cost_usd != null ? `$${spool.cost_usd.toFixed(2)}` : '—'}</span>
+                  </div>
+
+                  <div className="flex items-center justify-end gap-2 pt-1">
+                    <button className="flex items-center gap-1 rounded-md bg-slate-700 px-3 py-1.5 text-xs font-medium text-slate-200 hover:bg-slate-600">
+                      <Pencil size={12} /> Edit
+                    </button>
+                    <button
+                      onClick={() => setDeleteId(spool.id)}
+                      className="flex items-center gap-1 rounded-md bg-red-900/30 border border-red-700 px-3 py-1.5 text-xs font-medium text-red-300 hover:bg-red-900/50"
+                    >
+                      <Trash2 size={12} /> Delete
+                    </button>
+                  </div>
+                </div>
+              )
+            })}
+          </div>
+
+          {/* Pagination */}
+          <div className="flex items-center justify-between pt-2">
+            <span className="text-sm text-slate-400">
+              Showing {page * PAGE_SIZE + 1}–{Math.min((page + 1) * PAGE_SIZE, total)} of {total}
+            </span>
+            <div className="flex items-center gap-2">
+              <button
+                onClick={() => setPage(p => Math.max(0, p - 1))}
+                disabled={page === 0}
+                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+              >
+                <ChevronLeft size={16} />
+              </button>
+              <span className="text-sm text-slate-300 tabular-nums">{page + 1} / {totalPages}</span>
+              <button
+                onClick={() => setPage(p => Math.min(totalPages - 1, p + 1))}
+                disabled={page >= totalPages - 1}
+                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+              >
+                <ChevronRight size={16} />
+              </button>
+            </div>
+          </div>
+        </>
+      )}
+
+      {/* Delete confirmation modal */}
+      {deleteId !== null && (
+        <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm p-4">
+          <div className="w-full max-w-sm rounded-xl bg-slate-800 border border-slate-700 p-6 shadow-2xl space-y-4">
+            <div className="flex items-center gap-3">
+              <div className="flex h-10 w-10 items-center justify-center rounded-full bg-red-900/30">
+                <AlertTriangle size={20} className="text-red-400" />
+              </div>
+              <div>
+                <h3 className="text-lg font-semibold text-slate-100">Delete Spool?</h3>
+                <p className="text-sm text-slate-400">This action cannot be undone.</p>
+              </div>
+            </div>
+            <div className="flex justify-end gap-3">
+              <button
+                onClick={() => setDeleteId(null)}
+                className="rounded-lg bg-slate-700 px-4 py-2 text-sm font-medium text-slate-200 hover:bg-slate-600 transition-colors"
+              >
+                Cancel
+              </button>
+              <button
+                onClick={() => handleDelete(deleteId)}
+                className="rounded-lg bg-red-600 px-4 py-2 text-sm font-medium text-white hover:bg-red-500 transition-colors"
+              >
+                Delete
+              </button>
+            </div>
+          </div>
+        </div>
+      )}
+    </div>
+  )
+}

frontend/src/pages/PrintersPage.tsx

@@ -0,0 +1,262 @@
+import { useQuery } from '@tanstack/react-query'
+import { Printer, Wifi, WifiOff, HelpCircle, Plus, Globe, Radio } from 'lucide-react'
+import { fetchPrinters } from '../services/printerService'
+import LoadingSpinner from '../components/LoadingSpinner'
+import type { Printer as PrinterType, ConnectionStatus } from '../types/printer'
+
+function getConnectionStatus(printer: PrinterType): ConnectionStatus {
+  if (!printer.is_active) return 'offline'
+  if (printer.moonraker_url || printer.mqtt_broker_host) return 'online'
+  return 'unknown'
+}
+
+const statusConfig: Record<ConnectionStatus, { icon: typeof Wifi; label: string; className: string }> = {
+  online: {
+    icon: Wifi,
+    label: 'Online',
+    className: 'bg-emerald-900/30 border-emerald-700 text-emerald-300',
+  },
+  offline: {
+    icon: WifiOff,
+    label: 'Offline',
+    className: 'bg-red-900/30 border-red-700 text-red-300',
+  },
+  unknown: {
+    icon: HelpCircle,
+    label: 'Unknown',
+    className: 'bg-slate-700/50 border-slate-600 text-slate-400',
+  },
+}
+
+export default function PrintersPage() {
+  const { data: printers, isLoading, error, refetch } = useQuery({
+    queryKey: ['printers'],
+    queryFn: fetchPrinters,
+  })
+
+  const count = printers?.length ?? 0
+
+  return (
+    <div className="space-y-4">
+      {/* Header */}
+      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-3">
+        <div>
+          <h2 className="text-xl font-bold text-slate-100">Printers</h2>
+          <p className="text-sm text-slate-400">{count} printer(s) in fleet</p>
+        </div>
+        <button className="inline-flex items-center gap-2 rounded-lg bg-emerald-600 px-4 py-2 text-sm font-semibold text-white hover:bg-emerald-500 active:bg-emerald-700 transition-colors">
+          <Plus size={16} /> Add Printer
+        </button>
+      </div>
+
+      {/* Loading */}
+      {isLoading && (
+        <div className="flex items-center justify-center py-16">
+          <LoadingSpinner />
+        </div>
+      )}
+
+      {/* Error */}
+      {error && (
+        <div className="rounded-lg border border-red-700 bg-red-900/20 p-6 text-center">
+          <p className="text-red-400 mb-2">Failed to load printers.</p>
+          <button
+            onClick={() => refetch()}
+            className="text-sm text-red-300 underline hover:text-red-200"
+          >
+            Retry
+          </button>
+        </div>
+      )}
+
+      {/* Empty */}
+      {!isLoading && !error && printers?.length === 0 && (
+        <div className="rounded-lg border border-slate-700 bg-slate-800 p-12 text-center">
+          <Printer size={40} className="mx-auto mb-3 text-slate-500" />
+          <p className="text-slate-400">No printers found.</p>
+          <p className="text-sm text-slate-500 mt-1">
+            Add a printer to start monitoring your fleet.
+          </p>
+        </div>
+      )}
+
+      {/* Desktop Table */}
+      {!isLoading && !error && (printers?.length ?? 0) > 0 && (
+        <>
+          <div className="hidden lg:block overflow-x-auto rounded-lg border border-slate-700">
+            <table className="w-full text-sm">
+              <thead className="bg-slate-800 text-slate-300">
+                <tr>
+                  <th className="px-4 py-3 text-left font-semibold">Name</th>
+                  <th className="px-4 py-3 text-left font-semibold">Type</th>
+                  <th className="px-4 py-3 text-left font-semibold">Manufacturer</th>
+                  <th className="px-4 py-3 text-left font-semibold">Model</th>
+                  <th className="px-4 py-3 text-center font-semibold">Status</th>
+                  <th className="px-4 py-3 text-left font-semibold">Moonraker</th>
+                  <th className="px-4 py-3 text-left font-semibold">MQTT</th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-slate-700">
+                {printers!.map((printer) => {
+                  const status = getConnectionStatus(printer)
+                  const StatusIcon = statusConfig[status].icon
+                  return (
+                    <tr
+                      key={printer.id}
+                      className="bg-slate-800/50 hover:bg-slate-700/50 transition-colors"
+                    >
+                      <td className="px-4 py-3 font-medium text-slate-100">
+                        {printer.name}
+                      </td>
+                      <td className="px-4 py-3 text-slate-300">
+                        {printer.printer_type?.name ?? '—'}
+                      </td>
+                      <td className="px-4 py-3 text-slate-300">
+                        {printer.manufacturer || '—'}
+                      </td>
+                      <td className="px-4 py-3 text-slate-300">
+                        {printer.model || '—'}
+                      </td>
+                      <td className="px-4 py-3 text-center">
+                        <span
+                          className={`inline-flex items-center gap-1.5 rounded-full border px-2.5 py-0.5 text-xs font-medium ${statusConfig[status].className}`}
+                        >
+                          <StatusIcon size={12} />
+                          {statusConfig[status].label}
+                        </span>
+                      </td>
+                      <td className="px-4 py-3">
+                        {printer.moonraker_url ? (
+                          <a
+                            href={printer.moonraker_url}
+                            target="_blank"
+                            rel="noopener noreferrer"
+                            className="inline-flex items-center gap-1.5 text-sky-400 hover:text-sky-300 text-xs truncate max-w-[180px]"
+                            title={printer.moonraker_url}
+                          >
+                            <Globe size={12} className="shrink-0" />
+                            {printer.moonraker_url}
+                          </a>
+                        ) : (
+                          <span className="text-slate-500 text-xs">—</span>
+                        )}
+                      </td>
+                      <td className="px-4 py-3">
+                        {printer.mqtt_broker_host ? (
+                          <div className="space-y-0.5">
+                            <div className="inline-flex items-center gap-1.5 text-xs text-slate-300">
+                              <Radio size={12} className="shrink-0 text-amber-400" />
+                              <span className="truncate max-w-[140px]" title={printer.mqtt_broker_host}>
+                                {printer.mqtt_broker_host}
+                              </span>
+                            </div>
+                            {printer.mqtt_topic_prefix && (
+                              <div className="text-xs text-slate-500 ml-[20px] truncate max-w-[140px]" title={printer.mqtt_topic_prefix}>
+                                topic: {printer.mqtt_topic_prefix}
+                              </div>
+                            )}
+                            <div className="text-xs text-slate-500 ml-[20px]">
+                              TLS: {printer.mqtt_tls_enabled ? 'on' : 'off'}
+                            </div>
+                          </div>
+                        ) : (
+                          <span className="text-slate-500 text-xs">—</span>
+                        )}
+                      </td>
+                    </tr>
+                  )
+                })}
+              </tbody>
+            </table>
+          </div>
+
+          {/* Mobile / Tablet Cards */}
+          <div className="lg:hidden space-y-3">
+            {printers!.map((printer) => {
+              const status = getConnectionStatus(printer)
+              const StatusIcon = statusConfig[status].icon
+              return (
+                <div
+                  key={printer.id}
+                  className="rounded-lg border border-slate-700 bg-slate-800 p-4 space-y-3"
+                >
+                  {/* Top row: name + status */}
+                  <div className="flex items-start justify-between gap-3">
+                    <div className="min-w-0">
+                      <div className="font-semibold text-slate-100 truncate">
+                        {printer.name}
+                      </div>
+                      <div className="text-xs text-slate-400 mt-0.5">
+                        {[
+                          printer.printer_type?.name,
+                          printer.manufacturer,
+                          printer.model,
+                        ]
+                          .filter(Boolean)
+                          .join(' · ') || 'No details'}
+                      </div>
+                    </div>
+                    <span
+                      className={`inline-flex items-center gap-1.5 rounded-full border px-2.5 py-0.5 text-xs font-medium shrink-0 ${statusConfig[status].className}`}
+                    >
+                      <StatusIcon size={12} />
+                      {statusConfig[status].label}
+                    </span>
+                  </div>
+
+                  {/* Connection details */}
+                  <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
+                    {/* Moonraker */}
+                    <div className="rounded-md bg-slate-900/50 p-3 min-w-0">
+                      <div className="flex items-center gap-1.5 text-xs text-slate-400 mb-1">
+                        <Globe size={12} />
+                        Moonraker
+                      </div>
+                      {printer.moonraker_url ? (
+                        <a
+                          href={printer.moonraker_url}
+                          target="_blank"
+                          rel="noopener noreferrer"
+                          className="text-xs text-sky-400 hover:text-sky-300 break-all"
+                        >
+                          {printer.moonraker_url}
+                        </a>
+                      ) : (
+                        <span className="text-xs text-slate-500">Not configured</span>
+                      )}
+                    </div>
+
+                    {/* MQTT */}
+                    <div className="rounded-md bg-slate-900/50 p-3 min-w-0">
+                      <div className="flex items-center gap-1.5 text-xs text-slate-400 mb-1">
+                        <Radio size={12} />
+                        MQTT
+                      </div>
+                      {printer.mqtt_broker_host ? (
+                        <div className="space-y-0.5 text-xs text-slate-300">
+                          <div className="truncate" title={printer.mqtt_broker_host}>
+                            {printer.mqtt_broker_host}
+                          </div>
+                          {printer.mqtt_topic_prefix && (
+                            <div className="text-slate-500 truncate" title={printer.mqtt_topic_prefix}>
+                              topic: {printer.mqtt_topic_prefix}
+                            </div>
+                          )}
+                          <div className="text-slate-500">
+                            TLS: {printer.mqtt_tls_enabled ? 'on' : 'off'}
+                          </div>
+                        </div>
+                      ) : (
+                        <span className="text-xs text-slate-500">Not configured</span>
+                      )}
+                    </div>
+                  </div>
+                </div>
+              )
+            })}
+          </div>
+        </>
+      )}
+    </div>
+  )
+}

frontend/src/services/api.ts

@@ -0,0 +1,19 @@
+import axios from 'axios'
+import type { ListResponse, FilamentSpool, PrintJob } from '../types'
+
+const api = axios.create({
+  baseURL: '/api',
+  headers: { 'Content-Type': 'application/json' },
+})
+
+export async function getFilaments(params?: { low_stock?: boolean; limit?: number; offset?: number }) {
+  const res = await api.get<ListResponse<FilamentSpool>>('/filaments', { params })
+  return res.data
+}
+
+export async function getPrintJobs(params?: { limit?: number; offset?: number }) {
+  const res = await api.get<ListResponse<PrintJob>>('/print-jobs', { params })
+  return res.data
+}
+
+export default api

frontend/src/services/filamentService.ts

@@ -0,0 +1,24 @@
+import axios from 'axios'
+import type { FilamentSpool, ListResponse, FilamentFilter } from '../types/filament'
+
+const API_BASE = '/api'
+
+export async function fetchFilaments(filter: FilamentFilter): Promise<ListResponse<FilamentSpool>> {
+  const params = new URLSearchParams()
+  if (filter.material) params.set('material', filter.material)
+  if (filter.finish) params.set('finish', filter.finish)
+  if (filter.color) params.set('color', filter.color)
+  if (filter.low_stock) params.set('low_stock', 'true')
+  if (filter.search) params.set('search', filter.search)
+  if (filter.sort_by) params.set('sort_by', filter.sort_by)
+  if (filter.sort_dir) params.set('sort_dir', filter.sort_dir)
+  if (filter.limit !== undefined) params.set('limit', String(filter.limit))
+  if (filter.offset !== undefined) params.set('offset', String(filter.offset))
+
+  const res = await axios.get<ListResponse<FilamentSpool>>(`${API_BASE}/filaments?${params.toString()}`)
+  return res.data
+}
+
+export async function deleteFilament(id: number): Promise<void> {
+  await axios.delete(`${API_BASE}/filaments/${id}`)
+}

frontend/src/services/printerService.ts

@@ -0,0 +1,9 @@
+import axios from 'axios'
+import type { Printer, PrinterResponse } from '../types/printer'
+
+const API_BASE = '/api'
+
+export async function fetchPrinters(): Promise<Printer[]> {
+  const res = await axios.get<PrinterResponse>(`${API_BASE}/printers`)
+  return res.data.data
+}

frontend/src/types/filament.ts

@@ -0,0 +1,72 @@
+// Extrudex domain types
+
+export interface MaterialBase {
+  id: number
+  name: string
+  density_g_cm3: number
+  extrusion_temp_min?: number
+  extrusion_temp_max?: number
+  bed_temp_min?: number
+  bed_temp_max?: number
+  created_at: string
+  updated_at: string
+}
+
+export interface MaterialFinish {
+  id: number
+  name: string
+  description?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface MaterialModifier {
+  id: number
+  name: string
+  description?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface FilamentSpool {
+  id: number
+  name: string
+  material_base_id: number
+  material_base?: MaterialBase
+  material_finish_id: number
+  material_finish?: MaterialFinish
+  material_modifier_id?: number
+  material_modifier?: MaterialModifier
+  color_hex: string
+  brand?: string
+  diameter_mm: number
+  initial_grams: number
+  remaining_grams: number
+  spool_weight_grams?: number
+  cost_usd?: number
+  low_stock_threshold_grams: number
+  notes?: string
+  barcode?: string
+  deleted_at?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface ListResponse<T> {
+  data: T[]
+  total: number
+  limit: number
+  offset: number
+}
+
+export interface FilamentFilter {
+  material?: string
+  finish?: string
+  color?: string
+  low_stock?: boolean
+  search?: string
+  sort_by?: string
+  sort_dir?: 'asc' | 'desc'
+  limit?: number
+  offset?: number
+}

frontend/src/types/index.ts

@@ -0,0 +1,42 @@
+export interface FilamentSpool {
+  id: number;
+  name: string;
+  material_base_id: number;
+  material_finish_id: number;
+  material_modifier_id: number;
+  color_hex: string;
+  brand: string;
+  diameter_mm: number;
+  initial_grams: number;
+  remaining_grams: number;
+  spool_weight_grams: number;
+  cost_usd: number;
+  low_stock_threshold_grams: number;
+  notes: string;
+  barcode: string;
+  created_at: string;
+  updated_at: string;
+  deleted_at: string | null;
+}
+
+export interface PrintJob {
+  id: number;
+  name: string;
+  printer_id: number;
+  filament_id: number;
+  status: string;
+  duration_seconds: number;
+  filament_used_grams: number;
+  cost_usd: number;
+  started_at: string;
+  completed_at: string | null;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface ListResponse<T> {
+  data: T[];
+  total: number;
+  limit: number;
+  offset: number;
+}

frontend/src/types/printer.ts

@@ -0,0 +1,29 @@
+export interface PrinterType {
+  id: number
+  name: string
+  created_at: string
+  updated_at: string
+}
+
+export interface Printer {
+  id: number
+  name: string
+  printer_type_id: number
+  printer_type?: PrinterType
+  manufacturer?: string
+  model?: string
+  moonraker_url?: string
+  moonraker_api_key?: string
+  mqtt_broker_host?: string
+  mqtt_topic_prefix?: string
+  mqtt_tls_enabled: boolean
+  is_active: boolean
+  created_at: string
+  updated_at: string
+}
+
+export type ConnectionStatus = 'online' | 'offline' | 'unknown'
+
+export interface PrinterResponse {
+  data: Printer[]
+}

frontend/tsconfig.json

@@ -15,6 +15,7 @@
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "noFallthroughCasesInSwitch": true,
+    "ignoreDeprecations": "5.0",
     "baseUrl": ".",
     "paths": {
       "@/*": ["src/*"]