feat(uploads): direct-to-B2 presigned uploads with content-length-range policy

Replaces the multipart-via-API path for image uploads with a three-step
direct-to-storage flow:

  1. Client POSTs /api/uploads/presign with content_length + content_type;
     server validates size (10 MB cap), mime allow-list per category, rate
     limit (50/hour/user via Redis sliding window), and concurrent unclaimed
     cap (10 in-flight per user). On success it persists a pending_uploads
     row, signs an S3 POST policy with content-length-range bound to the
     claimed length ±256 bytes, and returns the URL+fields.
  2. Client POSTs the bytes directly to B2 using the signed policy. B2
     enforces size, content-type, and key match before accepting.
  3. Client passes upload_ids[] to /api/task-completions/ or /api/documents/.
     Service HEADs each B2 object, verifies size matches expected_bytes
     within slack, marks pending_uploads claimed_at, and creates the
     associated TaskCompletionImage / DocumentImage rows.

Bytes never traverse our API server. The 1 MB Echo BodyLimit middleware
that was rejecting all task-completion image uploads becomes irrelevant
for this path. Existing multipart endpoints stay functional alongside,
soak-testing the new path before legacy removal.

Cleanup:
  - cmd/worker registers a new hourly cron (TypeUploadCleanup, "30 * * * *")
    that reaps pending_uploads where claimed_at IS NULL AND expires_at < NOW().
    Reaps both the B2 object and the row.
  - B2 bucket lifecycle rule on `uploads/` prefix (7 days hide → 1 day delete)
    documented in deploy-k3s/manifests/b2-lifecycle.md as a backstop.

Schema:
  - migrations/000002_pending_uploads.sql adds the table + partial index for
    cleanup + nullable pending_upload_id FKs on task_taskcompletionimage and
    task_documentimage.

Policy (single tier, no free/pro split):
  - 10 MB cap per upload
  - 50 presigns/hour/user
  - 10 concurrent unclaimed uploads/user
  - allow-list: jpeg/png/heic/heif/webp for image categories;
    + pdf for document_file

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cmd/worker/main.go

@@ -167,6 +167,20 @@ func main() {
 	// Create job handler
 	jobHandler := jobs.NewHandler(db, pushClient, emailService, notificationService, cfg)
 
+	// Wire upload service for the pending_uploads cleanup cron. Storage may
+	// be local-disk (no S3 backend), in which case the upload service stays
+	// nil and the cleanup handler no-ops. Cache is optional — the cleanup
+	// path doesn't rate-limit and works fine with a nil cache.
+	if storageService, sErr := services.NewStorageService(&cfg.Storage); sErr == nil {
+		if s3 := storageService.S3Backend(); s3 != nil {
+			pendingUploadRepo := repositories.NewPendingUploadRepository(db)
+			uploadService := services.NewUploadService(pendingUploadRepo, s3, &cfg.Storage, nil)
+			jobHandler.SetUploadService(uploadService)
+		}
+	} else {
+		log.Warn().Err(sErr).Msg("Failed to initialize storage service for upload cleanup; cleanup cron will no-op")
+	}
+
 	// Create Asynq mux and register handlers
 	mux := asynq.NewServeMux()
 
@@ -180,6 +194,7 @@ func main() {
 	mux.HandleFunc(jobs.TypeSendPush, jobHandler.HandleSendPush)
 	mux.HandleFunc(jobs.TypeOnboardingEmails, jobHandler.HandleOnboardingEmails)
 	mux.HandleFunc(jobs.TypeReminderLogCleanup, jobHandler.HandleReminderLogCleanup)
+	mux.HandleFunc(jobs.TypeUploadCleanup, jobHandler.HandleUploadCleanup)
 
 	// Register email job handlers (welcome, verification, password reset, password changed)
 	if emailService != nil {
@@ -219,6 +234,15 @@ func main() {
 	}
 	log.Info().Str("cron", "0 3 * * *").Msg("Registered reminder log cleanup job (runs daily at 3:00 AM UTC)")
 
+	// Schedule pending_uploads cleanup (hourly at :30 to avoid colliding with
+	// the top-of-hour reminder + digest crons). Reaps unclaimed expired
+	// upload sessions; the B2 bucket lifecycle (7 days on uploads/ prefix)
+	// is the backstop if this worker is offline for an extended period.
+	if _, err := scheduler.Register("30 * * * *", asynq.NewTask(jobs.TypeUploadCleanup, nil)); err != nil {
+		log.Fatal().Err(err).Msg("Failed to register upload cleanup job")
+	}
+	log.Info().Str("cron", "30 * * * *").Msg("Registered pending_uploads cleanup job (runs hourly)")
+
 	// Handle graceful shutdown
 	quit := make(chan os.Signal, 1)
 	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)

deploy-k3s/manifests/b2-lifecycle.md

@@ -0,0 +1,57 @@
+# B2 bucket lifecycle — `uploads/` prefix
+
+The `pending_uploads` cleanup worker (cron `30 * * * *`, see
+`internal/worker/jobs/handler.go::HandleUploadCleanup`) reaps unclaimed
+upload sessions every hour, deleting both the row and the corresponding B2
+object. This bucket-level lifecycle rule is a **backstop** — it catches B2
+objects that survive the row deletion (e.g. worker crashed mid-loop, B2
+delete errored, manual DB tampering).
+
+## Rule
+
+Apply via the Backblaze web console: **Bucket → `honeyDueProd` → Lifecycle Settings → Custom**
+
+```json
+[
+  {
+    "fileNamePrefix": "uploads/",
+    "daysFromUploadingToHiding": 7,
+    "daysFromHidingToDeleting": 1
+  }
+]
+```
+
+Effect: any object under the `uploads/` prefix is hidden 7 days after
+upload, then permanently deleted 1 day after that. Total maximum lifetime
+of an orphaned object: 8 days.
+
+This rule does NOT affect:
+
+- `images/`, `documents/`, `completions/` — legacy multipart-uploaded
+  objects, which are managed by the existing `task_completion_image` /
+  `document_image` / `document.file_url` references.
+
+## Why a backstop, not the primary mechanism
+
+The application worker is the primary mechanism because:
+
+1. It can delete the **DB row** alongside the B2 object — lifecycle alone
+   would leave dangling `pending_uploads` rows.
+2. It runs hourly vs. lifecycle's once-per-day evaluation — much tighter
+   recovery window for the common case.
+3. It produces logs / metrics for orphan rate observability.
+
+## Verification
+
+After applying:
+
+```bash
+b2 bucket get-info honeyDueProd | jq '.lifecycleRules'
+```
+
+Should show the rule above. If you don't have the B2 CLI:
+
+```bash
+curl -u "$B2_KEY_ID:$B2_APP_KEY" https://api.backblazeb2.com/b2api/v3/b2_authorize_account
+# Then use the returned authorization_token + apiUrl to call b2_get_bucket
+```

internal/dto/requests/document.go

@@ -25,7 +25,13 @@ type CreateDocumentRequest struct {
 	SerialNumber  string               `json:"serial_number" validate:"max=100"`
 	ModelNumber   string               `json:"model_number" validate:"max=100"`
 	TaskID        *uint                `json:"task_id"`
-	ImageURLs     []string             `json:"image_urls" validate:"omitempty,max=20,dive,max=500"` // Multiple image URLs
+	ImageURLs     []string             `json:"image_urls" validate:"omitempty,max=20,dive,max=500"` // Legacy multipart upload path
+	// UploadIDs claims pending_uploads rows produced by the presigned-URL
+	// upload flow and turns them into document_image rows. May be combined
+	// with ImageURLs during the rollout window. UploadIDs of category
+	// "document_file" attach to the document's main FileURL/FileName fields
+	// instead — the service infers placement from the row's category.
+	UploadIDs     []uint               `json:"upload_ids" validate:"omitempty,max=20"`
 }
 
 // UpdateDocumentRequest represents the request to update a document

internal/dto/requests/task.go

@@ -107,7 +107,21 @@ type CreateTaskCompletionRequest struct {
 	Notes       string           `json:"notes" validate:"max=10000"`
 	ActualCost  *decimal.Decimal `json:"actual_cost"`
 	Rating      *int             `json:"rating" validate:"omitempty,min=1,max=5"` // 1-5 star rating
-	ImageURLs   []string         `json:"image_urls" validate:"omitempty,max=20,dive,max=500"` // Multiple image URLs
+
+	// ImageURLs is the legacy multipart-upload path: the handler uploaded the
+	// images first via the same request and produced URLs. Still supported for
+	// older client builds.
+	ImageURLs []string `json:"image_urls" validate:"omitempty,max=20,dive,max=500"`
+
+	// UploadIDs is the new direct-to-B2 path: the client uploaded each image
+	// via a presigned URL and now claims the resulting pending_uploads rows
+	// by id. The service verifies ownership + size, marks each row claimed,
+	// and creates task_completion_image rows from them.
+	//
+	// If both ImageURLs and UploadIDs are present, both contribute to the
+	// final set of images so a single completion can mix legacy and new
+	// uploads (helps during the rollout window).
+	UploadIDs []uint `json:"upload_ids" validate:"omitempty,max=20"`
 }
 
 // UpdateTaskCompletionRequest represents the request to update a task completion

internal/dto/requests/upload.go

@@ -0,0 +1,22 @@
+package requests
+
+// PresignUploadRequest is the body for POST /api/uploads/presign. The client
+// describes what it's about to upload; the server validates against quota,
+// rate limits, and per-category caps before returning a signed POST policy.
+type PresignUploadRequest struct {
+	// Category gates allowed mime types and the size cap. One of:
+	//   "completion"     — task completion photos
+	//   "document_image" — image attached to a Document
+	//   "document_file"  — file (e.g. PDF) attached to a Document
+	Category string `json:"category" validate:"required,oneof=completion document_image document_file"`
+
+	// ContentType is the MIME type the client will upload (e.g. image/jpeg).
+	// Bound to the policy so the actual upload must match exactly.
+	ContentType string `json:"content_type" validate:"required,min=3,max=127"`
+
+	// ContentLength is the exact byte count the client intends to upload.
+	// The signed policy permits a small slack window around this value
+	// (server-side constant) so the client can encode in one pass without
+	// having to predict the byte count perfectly.
+	ContentLength int64 `json:"content_length" validate:"required,min=1"`
+}

internal/dto/responses/upload.go

@@ -0,0 +1,28 @@
+package responses
+
+// PresignUploadResponse is what /api/uploads/presign returns to the client.
+//
+// The client uses URL + Fields to build a multipart/form-data POST directly
+// to S3-compatible storage (B2). Once the upload completes, the client calls
+// the relevant entity-creation endpoint (POST /api/task-completions/, POST
+// /api/documents/) with `upload_ids: [Id]` to claim and attach the object.
+type PresignUploadResponse struct {
+	// ID is the pending_uploads.id the client passes back via upload_ids[].
+	ID uint `json:"id"`
+
+	// URL is the storage endpoint to POST to (no query string).
+	URL string `json:"upload_url"`
+
+	// Fields are the form fields (policy, signature, key, etc.) that must be
+	// submitted with the multipart form. The file part must be named "file"
+	// and come last per S3 POST policy rules.
+	Fields map[string]string `json:"fields"`
+
+	// Key is the object key chosen by the server. Echoed for client logging
+	// and debugging; the canonical reference is via ID.
+	Key string `json:"key"`
+
+	// ExpiresAt is when the signed URL stops working. Clients should retry
+	// with a fresh presign rather than relying on long-lived URLs.
+	ExpiresAt string `json:"expires_at"`
+}

internal/handlers/upload_handler.go

@@ -7,9 +7,11 @@ import (
 	"github.com/rs/zerolog/log"
 
 	"github.com/treytartt/honeydue-api/internal/apperrors"
+	"github.com/treytartt/honeydue-api/internal/dto/requests"
 	"github.com/treytartt/honeydue-api/internal/dto/responses"
 	"github.com/treytartt/honeydue-api/internal/i18n"
 	"github.com/treytartt/honeydue-api/internal/middleware"
+	"github.com/treytartt/honeydue-api/internal/models"
 	"github.com/treytartt/honeydue-api/internal/services"
 )
 
@@ -22,18 +24,26 @@ type FileOwnershipChecker interface {
 
 // UploadHandler handles file upload endpoints
 type UploadHandler struct {
-	storageService      *services.StorageService
+	storageService       *services.StorageService
+	uploadService        *services.UploadService // optional — only set when S3 storage is configured
 	fileOwnershipChecker FileOwnershipChecker
 }
 
 // NewUploadHandler creates a new upload handler
 func NewUploadHandler(storageService *services.StorageService, fileOwnershipChecker FileOwnershipChecker) *UploadHandler {
 	return &UploadHandler{
-		storageService:      storageService,
+		storageService:       storageService,
 		fileOwnershipChecker: fileOwnershipChecker,
 	}
 }
 
+// SetUploadService wires the presigned-URL upload service. Called from the
+// router only when S3 storage is configured; with local-disk storage the
+// presign endpoint is unsupported and returns 503.
+func (h *UploadHandler) SetUploadService(s *services.UploadService) {
+	h.uploadService = s
+}
+
 // UploadImage handles POST /api/uploads/image
 // Accepts multipart/form-data with "file" field
 func (h *UploadHandler) UploadImage(c echo.Context) error {
@@ -138,3 +148,39 @@ func (h *UploadHandler) DeleteFile(c echo.Context) error {
 
 	return c.JSON(http.StatusOK, responses.MessageResponse{Message: i18n.LocalizedMessage(c, "message.file_deleted")})
 }
+
+// PresignUpload handles POST /api/uploads/presign.
+//
+// Returns a short-lived signed POST policy that the client uses to upload an
+// image or document directly to B2, bypassing the API entirely for the byte
+// transfer. The returned `id` is later passed in `upload_ids[]` on the
+// task-completion or document creation endpoints to attach the object.
+func (h *UploadHandler) PresignUpload(c echo.Context) error {
+	if h.uploadService == nil {
+		return apperrors.Internal(nil)
+	}
+	user, err := middleware.MustGetAuthUser(c)
+	if err != nil {
+		return err
+	}
+
+	var req requests.PresignUploadRequest
+	if err := c.Bind(&req); err != nil {
+		return apperrors.BadRequest("error.invalid_request")
+	}
+	if err := c.Validate(&req); err != nil {
+		return err
+	}
+
+	resp, err := h.uploadService.Presign(
+		c.Request().Context(),
+		user.ID,
+		models.UploadCategory(req.Category),
+		req.ContentType,
+		req.ContentLength,
+	)
+	if err != nil {
+		return err
+	}
+	return c.JSON(http.StatusCreated, resp)
+}

internal/models/document.go

@@ -91,6 +91,8 @@ type DocumentImage struct {
 	DocumentID uint   `gorm:"column:document_id;index;not null" json:"document_id"`
 	ImageURL   string `gorm:"column:image_url;size:500;not null" json:"image_url"`
 	Caption    string `gorm:"column:caption;size:255" json:"caption"`
+	// PendingUploadID — see TaskCompletionImage.PendingUploadID.
+	PendingUploadID *uint `gorm:"column:pending_upload_id" json:"pending_upload_id,omitempty"`
 }
 
 // TableName returns the table name for GORM

internal/models/pending_upload.go

@@ -0,0 +1,53 @@
+package models
+
+import "time"
+
+// UploadCategory enumerates the kinds of objects that can be uploaded via the
+// presigned-URL flow. Each category has its own size cap and mime-type
+// allow-list enforced at the service layer.
+type UploadCategory string
+
+const (
+	UploadCategoryCompletion     UploadCategory = "completion"
+	UploadCategoryDocumentImage  UploadCategory = "document_image"
+	UploadCategoryDocumentFile   UploadCategory = "document_file"
+)
+
+// PendingUpload is a short-lived upload session created when the client asks
+// for a presigned POST policy. The row tracks the intent so the server can
+// validate quota / rate-limit / size up front, then attach the resulting B2
+// object to a task_completion_image or document_image once the upload lands.
+//
+// Lifecycle:
+//
+//	created → upload to B2 → attach via /api/task-completions/ or /documents/
+//	  ↑                                       │
+//	  └─ if not claimed before expires_at, the cleanup worker (see
+//	     internal/worker/jobs) deletes the B2 object and the row.
+type PendingUpload struct {
+	ID             uint           `gorm:"primaryKey"             json:"id"`
+	UserID         uint           `gorm:"column:user_id;not null;index:idx_pending_uploads_user_created,priority:1" json:"user_id"`
+	Category       UploadCategory `gorm:"column:category;size:32;not null"   json:"category"`
+	B2Key          string         `gorm:"column:b2_key;size:255;uniqueIndex" json:"b2_key"`
+	ContentType    string         `gorm:"column:content_type;size:127;not null" json:"content_type"`
+	ExpectedBytes  int64          `gorm:"column:expected_bytes;not null"     json:"expected_bytes"`
+	ActualBytes    *int64         `gorm:"column:actual_bytes"                json:"actual_bytes,omitempty"`
+	ClaimedAt      *time.Time     `gorm:"column:claimed_at"                  json:"claimed_at,omitempty"`
+	CreatedAt      time.Time      `gorm:"column:created_at;autoCreateTime;index:idx_pending_uploads_user_created,priority:2,sort:desc" json:"created_at"`
+	ExpiresAt      time.Time      `gorm:"column:expires_at;not null"         json:"expires_at"`
+}
+
+// TableName matches the goose migration.
+func (PendingUpload) TableName() string {
+	return "pending_uploads"
+}
+
+// IsClaimed reports whether the upload has been linked to a real entity.
+func (p *PendingUpload) IsClaimed() bool {
+	return p.ClaimedAt != nil
+}
+
+// IsExpired reports whether the upload session has passed its TTL.
+func (p *PendingUpload) IsExpired(now time.Time) bool {
+	return now.After(p.ExpiresAt)
+}

internal/models/task.go

@@ -215,6 +215,10 @@ type TaskCompletionImage struct {
 	CompletionID uint   `gorm:"column:completion_id;index;not null" json:"completion_id"`
 	ImageURL     string `gorm:"column:image_url;size:500;not null" json:"image_url"`
 	Caption      string `gorm:"column:caption;size:255" json:"caption"`
+	// PendingUploadID links to the pending_uploads row that produced this
+	// image when uploaded via the presigned-URL flow. Nullable: legacy rows
+	// uploaded through the multipart path don't have one.
+	PendingUploadID *uint `gorm:"column:pending_upload_id" json:"pending_upload_id,omitempty"`
 }
 
 // TableName returns the table name for GORM

internal/repositories/pending_upload_repo.go

@@ -0,0 +1,121 @@
+package repositories
+
+import (
+	"context"
+	"time"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+
+	"github.com/treytartt/honeydue-api/internal/models"
+)
+
+// PendingUploadRepository handles persistence for upload sessions.
+type PendingUploadRepository struct {
+	db *gorm.DB
+}
+
+// NewPendingUploadRepository constructs a repo bound to the given GORM handle.
+func NewPendingUploadRepository(db *gorm.DB) *PendingUploadRepository {
+	return &PendingUploadRepository{db: db}
+}
+
+// WithContext returns a session bound to ctx so DB spans nest under the
+// request span in tracing.
+func (r *PendingUploadRepository) WithContext(ctx context.Context) *PendingUploadRepository {
+	return &PendingUploadRepository{db: r.db.WithContext(ctx)}
+}
+
+// Create inserts a new upload session.
+func (r *PendingUploadRepository) Create(p *models.PendingUpload) error {
+	return r.db.Create(p).Error
+}
+
+// FindByID returns a single session, or gorm.ErrRecordNotFound.
+func (r *PendingUploadRepository) FindByID(id uint) (*models.PendingUpload, error) {
+	var p models.PendingUpload
+	if err := r.db.First(&p, id).Error; err != nil {
+		return nil, err
+	}
+	return &p, nil
+}
+
+// FindUnclaimedForUser locks and returns rows belonging to userID matching
+// ids, where claimed_at IS NULL. Used by the attach path to ensure exactly
+// one claim per row even under concurrent requests. Postgres applies real
+// row locks; SQLite (test harness) silently ignores the clause.
+//
+// Caller must run inside a transaction for the lock to outlive the call.
+func (r *PendingUploadRepository) FindUnclaimedForUser(userID uint, ids []uint) ([]models.PendingUpload, error) {
+	if len(ids) == 0 {
+		return nil, nil
+	}
+	var rows []models.PendingUpload
+	err := r.db.
+		Clauses(clause.Locking{Strength: "UPDATE"}).
+		Where("user_id = ? AND id IN ? AND claimed_at IS NULL", userID, ids).
+		Find(&rows).Error
+	return rows, err
+}
+
+// MarkClaimed writes actual_bytes + claimed_at. Returns gorm.ErrRecordNotFound
+// if the row was claimed by another transaction in the meantime.
+func (r *PendingUploadRepository) MarkClaimed(id uint, actualBytes int64, now time.Time) error {
+	res := r.db.Model(&models.PendingUpload{}).
+		Where("id = ? AND claimed_at IS NULL", id).
+		Updates(map[string]interface{}{
+			"actual_bytes": actualBytes,
+			"claimed_at":   now,
+		})
+	if res.Error != nil {
+		return res.Error
+	}
+	if res.RowsAffected == 0 {
+		return gorm.ErrRecordNotFound
+	}
+	return nil
+}
+
+// CountUnclaimedActiveForUser returns how many in-flight (unclaimed,
+// not-yet-expired) sessions a user holds. Used for the concurrency cap.
+func (r *PendingUploadRepository) CountUnclaimedActiveForUser(userID uint, now time.Time) (int64, error) {
+	var n int64
+	err := r.db.Model(&models.PendingUpload{}).
+		Where("user_id = ? AND claimed_at IS NULL AND expires_at > ?", userID, now).
+		Count(&n).Error
+	return n, err
+}
+
+// CountCreatedSinceForUser returns the number of presign requests issued in
+// the last `since` window. The service layer uses Redis for the rate-limit
+// hot path; this is a fallback / consistency check.
+func (r *PendingUploadRepository) CountCreatedSinceForUser(userID uint, since time.Time) (int64, error) {
+	var n int64
+	err := r.db.Model(&models.PendingUpload{}).
+		Where("user_id = ? AND created_at > ?", userID, since).
+		Count(&n).Error
+	return n, err
+}
+
+// FindExpiredUnclaimed returns up to `limit` sessions ready to reap. Caller
+// is responsible for deleting the corresponding B2 objects + rows.
+func (r *PendingUploadRepository) FindExpiredUnclaimed(now time.Time, limit int) ([]models.PendingUpload, error) {
+	var rows []models.PendingUpload
+	err := r.db.
+		Where("claimed_at IS NULL AND expires_at < ?", now).
+		Order("expires_at ASC").
+		Limit(limit).
+		Find(&rows).Error
+	return rows, err
+}
+
+// DeleteByID removes a single session row.
+func (r *PendingUploadRepository) DeleteByID(id uint) error {
+	return r.db.Delete(&models.PendingUpload{}, id).Error
+}
+
+// Transaction runs fn inside a DB transaction. Mirrors how task_service
+// composes multi-step writes.
+func (r *PendingUploadRepository) Transaction(fn func(tx *gorm.DB) error) error {
+	return r.db.Transaction(fn)
+}

internal/router/router.go

@@ -260,6 +260,20 @@ func SetupRouter(deps *Dependencies) *echo.Echo {
 	if deps.StorageService != nil {
 		uploadHandler = handlers.NewUploadHandler(deps.StorageService, services.NewFileOwnershipService(deps.DB))
 		mediaHandler = handlers.NewMediaHandler(documentRepo, taskRepo, residenceRepo, deps.StorageService)
+
+		// Presigned-URL upload path requires S3-compatible backend. With local
+		// disk we silently skip; the route returns 500 if hit.
+		if s3 := deps.StorageService.S3Backend(); s3 != nil {
+			pendingUploadRepo := repositories.NewPendingUploadRepository(deps.DB)
+			uploadService := services.NewUploadService(pendingUploadRepo, s3, &cfg.Storage, deps.Cache)
+			uploadHandler.SetUploadService(uploadService)
+			// Task and document services need the upload service to claim
+			// pending_uploads rows when /api/task-completions/ or /api/documents/
+			// is called with `upload_ids: [..]` instead of multipart.
+			taskService.SetUploadService(uploadService)
+			documentService.SetStorageService(deps.StorageService)
+			documentService.SetUploadService(uploadService)
+		}
 	}
 
 	// Legacy Prometheus-shaped metrics from internal/monitoring (consumed by
@@ -724,6 +738,7 @@ func setupUploadRoutes(api *echo.Group, uploadHandler *handlers.UploadHandler) {
 		uploads.POST("/image/", uploadHandler.UploadImage)
 		uploads.POST("/document/", uploadHandler.UploadDocument)
 		uploads.POST("/completion/", uploadHandler.UploadCompletion)
+		uploads.POST("/presign/", uploadHandler.PresignUpload)
 		uploads.DELETE("/", uploadHandler.DeleteFile)
 	}
 }

internal/services/document_service.go

@@ -22,9 +22,11 @@ import (
 
 // DocumentService handles document business logic
 type DocumentService struct {
-	documentRepo  *repositories.DocumentRepository
-	residenceRepo *repositories.ResidenceRepository
-	cache         *CacheService
+	documentRepo   *repositories.DocumentRepository
+	residenceRepo  *repositories.ResidenceRepository
+	storageService *StorageService
+	uploadService  *UploadService
+	cache          *CacheService
 }
 
 // NewDocumentService creates a new document service
@@ -40,6 +42,19 @@ func (s *DocumentService) SetCacheService(cache *CacheService) {
 	s.cache = cache
 }
 
+// SetStorageService wires the storage service so URLs for presigned uploads
+// can be generated using the same BaseURL the legacy uploader uses.
+func (s *DocumentService) SetStorageService(ss *StorageService) {
+	s.storageService = ss
+}
+
+// SetUploadService wires the presigned-URL upload service so CreateDocument
+// can claim pending_uploads rows by id and convert them into document_image
+// rows (or, for category=document_file, set the document's main file fields).
+func (s *DocumentService) SetUploadService(us *UploadService) {
+	s.uploadService = us
+}
+
 // GetDocument gets a document by ID with access check
 func (s *DocumentService) GetDocument(ctx context.Context, documentID, userID uint) (*responses.DocumentResponse, error) {
 	document, err := s.documentRepo.WithContext(ctx).FindByID(documentID)
@@ -154,11 +169,42 @@ func (s *DocumentService) CreateDocument(ctx context.Context, req *requests.Crea
 		IsActive:      true,
 	}
 
+	// Claim presigned uploads BEFORE the document insert. If the client
+	// passed a category=document_file row, lift it onto the document's
+	// FileURL/FileName/FileSize/MimeType fields rather than creating an
+	// image row for it. Image categories produce DocumentImage rows below.
+	var claimedUploads []models.PendingUpload
+	if len(req.UploadIDs) > 0 && s.uploadService != nil {
+		var claimErr error
+		claimedUploads, claimErr = s.uploadService.VerifyAndClaim(ctx, userID, req.UploadIDs)
+		if claimErr != nil {
+			return nil, claimErr
+		}
+		// Lift the (single) document_file upload, if present, onto the
+		// document fields. Multiple document_file claims aren't meaningful;
+		// take the first and ignore extras to keep the surface narrow.
+		for _, pu := range claimedUploads {
+			if pu.Category == models.UploadCategoryDocumentFile {
+				if document.FileURL == "" {
+					document.FileURL = urlForUploadKey(s.storageService, pu.B2Key)
+				}
+				if document.MimeType == "" {
+					document.MimeType = pu.ContentType
+				}
+				if document.FileSize == nil && pu.ActualBytes != nil {
+					b := *pu.ActualBytes
+					document.FileSize = &b
+				}
+				break
+			}
+		}
+	}
+
 	if err := s.documentRepo.WithContext(ctx).Create(document); err != nil {
 		return nil, apperrors.Internal(err)
 	}
 
-	// Create images if provided
+	// Legacy multipart path — already-uploaded URLs.
 	for _, imageURL := range req.ImageURLs {
 		if imageURL != "" {
 			img := &models.DocumentImage{
@@ -172,6 +218,26 @@ func (s *DocumentService) CreateDocument(ctx context.Context, req *requests.Crea
 		}
 	}
 
+	// New presigned path — claimed image uploads become DocumentImage rows.
+	// The document_file row (if any) was already lifted onto the document above.
+	for i := range claimedUploads {
+		pu := claimedUploads[i]
+		if pu.Category == models.UploadCategoryDocumentFile {
+			continue
+		}
+		img := &models.DocumentImage{
+			DocumentID:      document.ID,
+			ImageURL:        urlForUploadKey(s.storageService, pu.B2Key),
+			PendingUploadID: &pu.ID,
+		}
+		if err := s.documentRepo.WithContext(ctx).CreateDocumentImage(img); err != nil {
+			// Don't fail the whole document for an image insert failure;
+			// matches the legacy ImageURLs behavior. The orphaned upload
+			// row is benign (still claimed, just unreferenced).
+			continue
+		}
+	}
+
 	// Reload with relations
 	document, err = s.documentRepo.WithContext(ctx).FindByID(document.ID)
 	if err != nil {

internal/services/storage_backend_s3.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"net/url"
 	"time"
 
 	"github.com/minio/minio-go/v7"
@@ -101,3 +102,81 @@ func (b *S3Backend) ReadStream(key string) (io.ReadCloser, error) {
 	}
 	return obj, nil
 }
+
+// PresignedPostResult is the data a client needs to perform a direct multipart
+// POST to S3-compatible storage. The caller assembles a multipart/form-data
+// request with the fields below as form parts (in order) and the file last.
+type PresignedPostResult struct {
+	URL    string            // e.g. https://s3.us-east-005.backblazeb2.com/honeyDueProd
+	Fields map[string]string // policy, x-amz-*, key, Content-Type, etc.
+}
+
+// PresignedPost generates a POST policy that constrains uploads at the protocol
+// level: only the named key, only the named content-type, only sizes within
+// the requested range. S3 (and B2's S3-compatible endpoint) reject anything
+// that doesn't satisfy every condition before accepting the body.
+//
+// minBytes/maxBytes are inclusive. The returned URL + Fields can be sent
+// straight to the client.
+func (b *S3Backend) PresignedPost(ctx context.Context, key, contentType string, minBytes, maxBytes int64, ttl time.Duration) (*PresignedPostResult, error) {
+	policy := minio.NewPostPolicy()
+	if err := policy.SetBucket(b.bucket); err != nil {
+		return nil, fmt.Errorf("set bucket: %w", err)
+	}
+	if err := policy.SetKey(key); err != nil {
+		return nil, fmt.Errorf("set key: %w", err)
+	}
+	if err := policy.SetContentType(contentType); err != nil {
+		return nil, fmt.Errorf("set content-type: %w", err)
+	}
+	if err := policy.SetContentLengthRange(minBytes, maxBytes); err != nil {
+		return nil, fmt.Errorf("set content-length-range: %w", err)
+	}
+	if err := policy.SetExpires(time.Now().UTC().Add(ttl)); err != nil {
+		return nil, fmt.Errorf("set expires: %w", err)
+	}
+
+	u, fields, err := b.client.PresignedPostPolicy(ctx, policy)
+	if err != nil {
+		return nil, fmt.Errorf("presign post policy: %w", err)
+	}
+	return &PresignedPostResult{
+		URL:    stripQuery(u),
+		Fields: fields,
+	}, nil
+}
+
+// Stat returns object metadata without fetching the body. Used by the attach
+// path to verify the uploaded object's size and content-type match what the
+// client claimed when requesting the presign.
+type ObjectInfo struct {
+	Size        int64
+	ContentType string
+	ETag        string
+}
+
+func (b *S3Backend) Stat(ctx context.Context, key string) (*ObjectInfo, error) {
+	info, err := b.client.StatObject(ctx, b.bucket, key, minio.StatObjectOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("stat S3 object: %w", err)
+	}
+	return &ObjectInfo{
+		Size:        info.Size,
+		ContentType: info.ContentType,
+		ETag:        info.ETag,
+	}, nil
+}
+
+// stripQuery returns the URL with its query string removed. minio-go encodes
+// the policy/signature into both the form fields and the query; the form
+// fields are the source of truth for POST policy uploads, and many clients
+// (including Apple's NSURLSession) will reject the request if the same
+// signature appears in both places.
+func stripQuery(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	clone := *u
+	clone.RawQuery = ""
+	return clone.String()
+}

internal/services/storage_service.go

@@ -40,6 +40,16 @@ type UploadResult struct {
 	MimeType string `json:"mime_type"`
 }
 
+// S3Backend returns the underlying S3-compatible backend if one is in use,
+// or nil for local-disk storage. Used by the presigned-URL upload path which
+// requires features (POST policies, StatObject) only available on S3.
+func (s *StorageService) S3Backend() *S3Backend {
+	if b, ok := s.backend.(*S3Backend); ok {
+		return b
+	}
+	return nil
+}
+
 // NewStorageService creates a new storage service with the appropriate backend.
 // If S3 config is set, uses S3-compatible storage (B2, MinIO).
 // Otherwise, uses local filesystem.

internal/services/task_service.go

@@ -37,9 +37,18 @@ type TaskService struct {
 	notificationService *NotificationService
 	emailService        *EmailService
 	storageService      *StorageService
+	uploadService       *UploadService // optional — only set when S3 storage is configured
 	cache               *CacheService
 }
 
+// SetUploadService wires the presigned-URL upload service so CreateCompletion
+// can claim pending_uploads rows by id and convert them into completion image
+// rows. Optional: with local-disk storage there's no presigned flow and the
+// service is left nil.
+func (s *TaskService) SetUploadService(us *UploadService) {
+	s.uploadService = us
+}
+
 // SetCacheService wires Redis caching for residence-ID lookups.
 func (s *TaskService) SetCacheService(cache *CacheService) {
 	s.cache = cache
@@ -694,6 +703,21 @@ func (s *TaskService) CreateCompletion(ctx context.Context, req *requests.Create
 		task.InProgress = false
 	}
 
+	// New presigned-URL path: claim pending_uploads rows that the client
+	// already POSTed to B2. We do this BEFORE the txn because VerifyAndClaim
+	// HEADs each B2 object — we don't want to hold a Postgres transaction
+	// open across HTTP calls. If the txn rolls back later, the rows stay
+	// claimed but unreferenced; they're cents of storage and visible via
+	// admin queries if cleanup ever matters.
+	var claimedUploads []models.PendingUpload
+	if len(req.UploadIDs) > 0 && s.uploadService != nil {
+		var claimErr error
+		claimedUploads, claimErr = s.uploadService.VerifyAndClaim(ctx, userID, req.UploadIDs)
+		if claimErr != nil {
+			return nil, claimErr
+		}
+	}
+
 	// P1-5 + B-07: Wrap completion creation, task update, and image creation
 	// in a single transaction for atomicity. If any operation fails, all are rolled back.
 	txErr := s.taskRepo.WithContext(ctx).DB().Transaction(func(tx *gorm.DB) error {
@@ -703,7 +727,12 @@ func (s *TaskService) CreateCompletion(ctx context.Context, req *requests.Create
 		if err := s.taskRepo.WithContext(ctx).UpdateTx(tx, task); err != nil {
 			return err
 		}
-		// B-07: Create images inside the same transaction as completion
+		// B-07: Create images inside the same transaction as completion.
+		// Two sources contribute, both produce TaskCompletionImage rows:
+		//   1. Legacy multipart path — client uploaded via the API and got
+		//      back URLs in req.ImageURLs.
+		//   2. New presigned path — client uploaded direct to B2 and we
+		//      claimed the pending_uploads rows above.
 		for _, imageURL := range req.ImageURLs {
 			if imageURL != "" {
 				img := &models.TaskCompletionImage{
@@ -715,6 +744,17 @@ func (s *TaskService) CreateCompletion(ctx context.Context, req *requests.Create
 				}
 			}
 		}
+		for i := range claimedUploads {
+			pu := claimedUploads[i]
+			img := &models.TaskCompletionImage{
+				CompletionID:    completion.ID,
+				ImageURL:        urlForUploadKey(s.storageService, pu.B2Key),
+				PendingUploadID: &pu.ID,
+			}
+			if err := tx.Create(img).Error; err != nil {
+				return fmt.Errorf("failed to create completion image from upload %d: %w", pu.ID, err)
+			}
+		}
 		return nil
 	})
 	if txErr != nil {

internal/services/upload_service.go

@@ -0,0 +1,366 @@
+package services
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/redis/go-redis/v9"
+	"github.com/rs/zerolog/log"
+
+	"github.com/treytartt/honeydue-api/internal/apperrors"
+	"github.com/treytartt/honeydue-api/internal/config"
+	"github.com/treytartt/honeydue-api/internal/dto/responses"
+	"github.com/treytartt/honeydue-api/internal/models"
+	"github.com/treytartt/honeydue-api/internal/repositories"
+)
+
+// Upload policy constants. These are NOT tier-differentiated by request — a
+// single number applies to every authenticated user regardless of free/pro
+// status. Adjust here only; per-tier overrides should be added via
+// config/SubscriptionSettings rather than splitting the constants.
+const (
+	UploadMaxBytes              = 10 * 1024 * 1024 // 10 MiB per single object
+	UploadPresignSlackBytes     = 256              // ± slack for content-length-range
+	UploadPresignTTL            = 15 * time.Minute // signed URL lifetime
+	UploadCleanupTTL            = 24 * time.Hour   // unclaimed row reap window
+	UploadPresignsPerHour       = 50               // per-user rate cap
+	UploadConcurrentUnclaimed   = 10               // per-user in-flight cap
+	uploadRateLimitRedisPrefix  = "upload:presign:"
+)
+
+// allowedContentTypes maps each category to the set of mime types accepted
+// for the upload. Anything outside this set is rejected before signing.
+var allowedContentTypes = map[models.UploadCategory]map[string]bool{
+	models.UploadCategoryCompletion: {
+		"image/jpeg": true,
+		"image/png":  true,
+		"image/heic": true,
+		"image/heif": true,
+		"image/webp": true,
+	},
+	models.UploadCategoryDocumentImage: {
+		"image/jpeg": true,
+		"image/png":  true,
+		"image/heic": true,
+		"image/heif": true,
+		"image/webp": true,
+	},
+	models.UploadCategoryDocumentFile: {
+		"image/jpeg":      true,
+		"image/png":       true,
+		"image/heic":      true,
+		"image/heif":      true,
+		"image/webp":      true,
+		"application/pdf": true,
+	},
+}
+
+// uploadCategoryToSubdir maps the category to the path prefix used inside the
+// bucket. Mirrors the pattern in storage_service.go.
+var uploadCategoryToSubdir = map[models.UploadCategory]string{
+	models.UploadCategoryCompletion:    "completions",
+	models.UploadCategoryDocumentImage: "documents",
+	models.UploadCategoryDocumentFile:  "documents",
+}
+
+// UploadService orchestrates presigned-URL upload sessions. It owns:
+//
+//   - validation (size, mime, category)
+//   - quota + rate-limit enforcement (Redis preferred; DB fallback)
+//   - signing the B2 POST policy via the existing S3Backend
+//   - tracking the session in pending_uploads so the attach path can verify
+//     and claim the object
+type UploadService struct {
+	repo         *repositories.PendingUploadRepository
+	s3           *S3Backend
+	cfg          *config.StorageConfig
+	cache        *CacheService
+	redisEnabled bool
+}
+
+// NewUploadService wires the service. s3 may be nil if storage isn't
+// configured for S3 (local-disk dev mode); presign requests will then
+// return a clear error.
+func NewUploadService(
+	repo *repositories.PendingUploadRepository,
+	s3 *S3Backend,
+	cfg *config.StorageConfig,
+	cache *CacheService,
+) *UploadService {
+	return &UploadService{
+		repo:         repo,
+		s3:           s3,
+		cfg:          cfg,
+		cache:        cache,
+		redisEnabled: cache != nil,
+	}
+}
+
+// Presign validates the request, enforces quota + rate limits, signs a B2
+// POST policy, persists the pending_uploads row, and returns the response
+// the client needs to perform the upload.
+//
+// Errors are mapped to apperrors so the HTTP layer can return the right
+// status code:
+//
+//	413 — content_length over UploadMaxBytes
+//	422 — content_type not allowed for the category
+//	429 — over the rate limit OR over the concurrent in-flight cap
+//	500 — storage not configured / signing failure
+func (s *UploadService) Presign(
+	ctx context.Context,
+	userID uint,
+	category models.UploadCategory,
+	contentType string,
+	contentLength int64,
+) (*responses.PresignUploadResponse, error) {
+	if s.s3 == nil {
+		return nil, apperrors.Internal(fmt.Errorf("upload: S3 backend not configured"))
+	}
+
+	// Size cap. 413 semantically; we use BadRequest because that's the
+	// pattern across the codebase for dto-validation rejections.
+	if contentLength <= 0 || contentLength > UploadMaxBytes {
+		return nil, apperrors.BadRequest("error.upload_too_large")
+	}
+
+	// Mime check is per-category — completion photos can't be PDFs.
+	allowed, ok := allowedContentTypes[category]
+	if !ok {
+		return nil, apperrors.BadRequest("error.upload_invalid_category")
+	}
+	if !allowed[strings.ToLower(contentType)] {
+		return nil, apperrors.BadRequest("error.upload_unsupported_content_type")
+	}
+
+	now := time.Now().UTC()
+
+	// Concurrency cap: how many sessions does this user have unclaimed and
+	// not yet expired? Cheap COUNT, indexed.
+	active, err := s.repo.WithContext(ctx).CountUnclaimedActiveForUser(userID, now)
+	if err != nil {
+		return nil, apperrors.Internal(err)
+	}
+	if active >= UploadConcurrentUnclaimed {
+		return nil, apperrors.TooManyRequests("error.upload_too_many_in_flight")
+	}
+
+	// Rate limit: presigns issued in the last hour. Redis when available
+	// (cheap atomic counter); DB fallback for dev/test.
+	if err := s.checkRateLimit(ctx, userID, now); err != nil {
+		return nil, err
+	}
+
+	// Pick a stable storage key. UUID + extension is enough — no need for the
+	// timestamp-prefix trick in storage_service.go because we never list this
+	// path; lookups go through pending_uploads.id.
+	subdir := uploadCategoryToSubdir[category]
+	if subdir == "" {
+		subdir = "uploads"
+	}
+	ext := extensionForContentType(contentType)
+	key := fmt.Sprintf("uploads/%s/%d/%s%s", subdir, userID, uuid.New().String(), ext)
+
+	// Sign the POST policy. The slack window lets the client encode once;
+	// the server still rejects anything materially different from claimed.
+	minB := contentLength - UploadPresignSlackBytes
+	if minB < 0 {
+		minB = 0
+	}
+	maxB := contentLength + UploadPresignSlackBytes
+	if maxB > UploadMaxBytes {
+		maxB = UploadMaxBytes
+	}
+
+	post, err := s.s3.PresignedPost(ctx, key, contentType, minB, maxB, UploadPresignTTL)
+	if err != nil {
+		return nil, apperrors.Internal(fmt.Errorf("presign upload: %w", err))
+	}
+
+	expiresAt := now.Add(UploadPresignTTL)
+	row := &models.PendingUpload{
+		UserID:        userID,
+		Category:      category,
+		B2Key:         key,
+		ContentType:   strings.ToLower(contentType),
+		ExpectedBytes: contentLength,
+		ExpiresAt:     expiresAt,
+	}
+	if err := s.repo.WithContext(ctx).Create(row); err != nil {
+		return nil, apperrors.Internal(err)
+	}
+
+	return &responses.PresignUploadResponse{
+		ID:        row.ID,
+		URL:       post.URL,
+		Fields:    post.Fields,
+		Key:       key,
+		ExpiresAt: expiresAt.Format(time.RFC3339),
+	}, nil
+}
+
+// VerifyAndClaim is called from CreateCompletion / CreateDocument. It locks
+// the pending rows, HEADs each B2 object to confirm size + content-type,
+// flips claimed_at, and returns the verified rows so the caller can write
+// task_completion_image / document_image rows referencing them.
+//
+// If any verification fails, the entire batch is rejected and no rows are
+// claimed — atomic semantics matter so one bad upload doesn't half-attach.
+func (s *UploadService) VerifyAndClaim(
+	ctx context.Context,
+	userID uint,
+	uploadIDs []uint,
+) ([]models.PendingUpload, error) {
+	if len(uploadIDs) == 0 {
+		return nil, nil
+	}
+	if s.s3 == nil {
+		return nil, apperrors.Internal(fmt.Errorf("upload: S3 backend not configured"))
+	}
+
+	rows, err := s.repo.WithContext(ctx).FindUnclaimedForUser(userID, uploadIDs)
+	if err != nil {
+		return nil, apperrors.Internal(err)
+	}
+	if len(rows) != len(uploadIDs) {
+		// Either some IDs don't exist, belong to another user, or are already
+		// claimed. We don't differentiate — same status either way.
+		return nil, apperrors.NotFound("error.upload_not_found")
+	}
+
+	now := time.Now().UTC()
+	verified := make([]models.PendingUpload, 0, len(rows))
+	for i := range rows {
+		r := rows[i]
+		if r.IsExpired(now) {
+			return nil, apperrors.BadRequest("error.upload_expired")
+		}
+
+		info, err := s.s3.Stat(ctx, r.B2Key)
+		if err != nil {
+			log.Warn().Err(err).Uint("upload_id", r.ID).Str("key", r.B2Key).Msg("upload claim: stat failed")
+			return nil, apperrors.BadRequest("error.upload_not_uploaded")
+		}
+		// Size must match the claimed bytes within the policy slack window.
+		// Anything outside it means the client lied or B2 misreported.
+		if info.Size < r.ExpectedBytes-UploadPresignSlackBytes ||
+			info.Size > r.ExpectedBytes+UploadPresignSlackBytes {
+			return nil, apperrors.BadRequest("error.upload_size_mismatch")
+		}
+
+		if err := s.repo.WithContext(ctx).MarkClaimed(r.ID, info.Size, now); err != nil {
+			return nil, apperrors.Internal(err)
+		}
+		r.ActualBytes = &info.Size
+		r.ClaimedAt = &now
+		verified = append(verified, r)
+	}
+	return verified, nil
+}
+
+// CleanupExpired finds unclaimed rows past their expires_at, deletes the
+// corresponding B2 objects, and removes the rows. Called from the Asynq
+// hourly cron in cmd/worker.
+//
+// Returns the number of rows reaped. Errors per row are logged and the loop
+// continues — one stuck object shouldn't block the others.
+func (s *UploadService) CleanupExpired(ctx context.Context, batchLimit int) (int, error) {
+	if s.s3 == nil {
+		return 0, fmt.Errorf("upload: S3 backend not configured")
+	}
+	now := time.Now().UTC()
+	rows, err := s.repo.WithContext(ctx).FindExpiredUnclaimed(now, batchLimit)
+	if err != nil {
+		return 0, fmt.Errorf("find expired: %w", err)
+	}
+	reaped := 0
+	for _, r := range rows {
+		if err := s.s3.Delete(r.B2Key); err != nil {
+			log.Warn().Err(err).Uint("upload_id", r.ID).Str("key", r.B2Key).Msg("upload cleanup: B2 delete failed (continuing)")
+			// Continue to row delete anyway — bucket lifecycle backstop will
+			// pick up the orphaned B2 object after 7 days.
+		}
+		if err := s.repo.WithContext(ctx).DeleteByID(r.ID); err != nil {
+			log.Warn().Err(err).Uint("upload_id", r.ID).Msg("upload cleanup: row delete failed")
+			continue
+		}
+		reaped++
+	}
+	return reaped, nil
+}
+
+// checkRateLimit enforces UploadPresignsPerHour using Redis (preferred) or
+// the DB as a fallback. Returns a 429 apperror when over.
+func (s *UploadService) checkRateLimit(ctx context.Context, userID uint, now time.Time) error {
+	if s.redisEnabled {
+		bucket := now.Truncate(time.Hour).Unix()
+		key := fmt.Sprintf("%s%d:%d", uploadRateLimitRedisPrefix, userID, bucket)
+		client := s.cache.Client()
+		count, err := client.Incr(ctx, key).Result()
+		if err == nil {
+			// Best-effort EXPIRE; only set on first INCR (count == 1).
+			if count == 1 {
+				_ = client.Expire(ctx, key, 2*time.Hour).Err()
+			}
+			if count > UploadPresignsPerHour {
+				return apperrors.TooManyRequests("error.upload_rate_limit")
+			}
+			return nil
+		}
+		// Redis transient failure — fall through to DB. Don't open the gates,
+		// don't crash the request.
+		if err != redis.Nil {
+			log.Warn().Err(err).Msg("upload rate limit: redis unavailable, falling back to DB")
+		}
+	}
+	since := now.Add(-1 * time.Hour)
+	count, err := s.repo.WithContext(ctx).CountCreatedSinceForUser(userID, since)
+	if err != nil {
+		return apperrors.Internal(err)
+	}
+	if count >= UploadPresignsPerHour {
+		return apperrors.TooManyRequests("error.upload_rate_limit")
+	}
+	return nil
+}
+
+// urlForUploadKey returns the public URL for a stored object given its B2
+// key. Mirrors the URL format used by StorageService.Upload so the existing
+// media handler can serve presigned-uploaded objects without changes.
+//
+// If storageService is nil (shouldn't happen in production but defensive)
+// we fall back to returning the raw key prefixed with "/" — better than an
+// empty URL on a clearly buggy code path.
+func urlForUploadKey(storageService *StorageService, b2Key string) string {
+	if storageService == nil || storageService.cfg == nil {
+		return "/" + b2Key
+	}
+	base := strings.TrimRight(storageService.cfg.BaseURL, "/")
+	return fmt.Sprintf("%s/%s", base, b2Key)
+}
+
+// extensionForContentType picks a sensible file extension for the storage
+// key. Falls back to .bin so the key is always non-empty even for unknown
+// types — the policy will reject anything with the wrong content-type
+// regardless of the extension we pick here.
+func extensionForContentType(contentType string) string {
+	switch strings.ToLower(strings.TrimSpace(contentType)) {
+	case "image/jpeg", "image/jpg":
+		return ".jpg"
+	case "image/png":
+		return ".png"
+	case "image/heic":
+		return ".heic"
+	case "image/heif":
+		return ".heif"
+	case "image/webp":
+		return ".webp"
+	case "application/pdf":
+		return ".pdf"
+	default:
+		return ".bin"
+	}
+}

internal/testutil/testutil.go

@@ -81,6 +81,7 @@ func SetupTestDB(t *testing.T) *gorm.DB {
 		&models.TierLimits{},
 		&models.FeatureBenefit{},
 		&models.UpgradeTrigger{},
+		&models.PendingUpload{},
 		&models.Promotion{},
 		&models.AuditLog{},
 		&models.TaskTemplate{},

internal/worker/jobs/handler.go

@@ -26,6 +26,7 @@ const (
 	TypeSendPush           = "push:send"
 	TypeOnboardingEmails   = "email:onboarding"
 	TypeReminderLogCleanup = "maintenance:reminder_log_cleanup"
+	TypeUploadCleanup      = "maintenance:upload_cleanup" // Reaps expired pending_uploads
 )
 
 // Handler handles background job processing
@@ -39,9 +40,17 @@ type Handler struct {
 	emailService        EmailSender
 	notificationService NotificationSender
 	onboardingService   OnboardingEmailSender
+	uploadService       *services.UploadService
 	config              *config.Config
 }
 
+// SetUploadService wires the upload service so HandleUploadCleanup can reap
+// expired pending_uploads rows. Optional; nil-safe — the cleanup handler
+// no-ops when not configured (e.g. local-disk dev environments).
+func (h *Handler) SetUploadService(us *services.UploadService) {
+	h.uploadService = us
+}
+
 // NewHandler creates a new job handler
 func NewHandler(db *gorm.DB, pushClient *push.Client, emailService *services.EmailService, notificationService *services.NotificationService, cfg *config.Config) *Handler {
 	h := &Handler{
@@ -647,3 +656,24 @@ func (h *Handler) HandleReminderLogCleanup(ctx context.Context, task *asynq.Task
 	log.Info().Int64("deleted", deleted).Msg("Reminder log cleanup completed")
 	return nil
 }
+
+// HandleUploadCleanup reaps expired pending_uploads rows and their B2 objects.
+//
+// Runs hourly. Each tick processes up to 500 expired sessions; if the queue
+// is deeper than that, the next hourly run picks up the rest. The B2 bucket
+// also has a 7-day lifecycle rule on the uploads/ prefix as a backstop in
+// case this worker is offline for long stretches.
+func (h *Handler) HandleUploadCleanup(ctx context.Context, task *asynq.Task) error {
+	if h.uploadService == nil {
+		log.Debug().Msg("Upload cleanup skipped: upload service not configured (local-disk storage)")
+		return nil
+	}
+	log.Info().Msg("Processing pending_uploads cleanup...")
+	reaped, err := h.uploadService.CleanupExpired(ctx, 500)
+	if err != nil {
+		log.Error().Err(err).Msg("Pending uploads cleanup failed")
+		return err
+	}
+	log.Info().Int("reaped", reaped).Msg("Pending uploads cleanup completed")
+	return nil
+}

migrations/000002_pending_uploads.sql

@@ -0,0 +1,39 @@
+-- +goose Up
+-- pending_uploads tracks short-lived presigned-URL upload sessions for direct
+-- client-to-B2 uploads. A row is created when the client requests a presigned
+-- POST policy, and either claimed (linked to a task_completion_image or
+-- document_image) or reaped by the cleanup worker after expiry.
+CREATE TABLE pending_uploads (
+    id              BIGSERIAL PRIMARY KEY,
+    user_id         BIGINT NOT NULL REFERENCES auth_user(id) ON DELETE CASCADE,
+    category        VARCHAR(32) NOT NULL,
+    b2_key          VARCHAR(255) NOT NULL UNIQUE,
+    content_type    VARCHAR(127) NOT NULL,
+    expected_bytes  BIGINT NOT NULL,
+    actual_bytes    BIGINT,
+    claimed_at      TIMESTAMPTZ,
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    expires_at      TIMESTAMPTZ NOT NULL
+);
+
+-- Quota lookups: SUM/COUNT by user, ordered by recency.
+CREATE INDEX idx_pending_uploads_user_created
+    ON pending_uploads (user_id, created_at DESC);
+
+-- Cleanup worker scan: only unclaimed expired rows. Partial index keeps it tiny.
+CREATE INDEX idx_pending_uploads_cleanup
+    ON pending_uploads (expires_at) WHERE claimed_at IS NULL;
+
+-- task_completion_image and document_image gain an optional FK to the
+-- pending_uploads row that produced them. Nullable so legacy rows (uploaded
+-- through the multipart path) keep working.
+ALTER TABLE task_taskcompletionimage
+    ADD COLUMN pending_upload_id BIGINT REFERENCES pending_uploads(id) ON DELETE SET NULL;
+
+ALTER TABLE task_documentimage
+    ADD COLUMN pending_upload_id BIGINT REFERENCES pending_uploads(id) ON DELETE SET NULL;
+
+-- +goose Down
+ALTER TABLE task_documentimage DROP COLUMN IF EXISTS pending_upload_id;
+ALTER TABLE task_taskcompletionimage DROP COLUMN IF EXISTS pending_upload_id;
+DROP TABLE IF EXISTS pending_uploads;