feat(upload): support batching via header and update ShareX config

Introduce support for grouping multiple sequential file uploads into a single box using the `X-Warpbox-Batch` header. This is particularly useful for ShareX multi-file selections, which are sent as separate back-to-back requests.

Additionally, this change:
- Updates the ShareX configuration template to opt-in to batching by default.
- Switches ShareX configuration placeholders to the modern `{json:...}` format.
- Adds `thumbnailUrl` to the upload response schema and documents its usage.

backend/libs/handlers/api_docs.go

@@ -17,6 +17,7 @@ type apiDocsData struct {
 	ShareXExampleURL    string
 	ShareXDownloadURL   string
 	ShareXFileFieldName string
+	ShareXGroupWindow   string
 }
 
 func (a *App) APIDocs(w http.ResponseWriter, r *http.Request) {
@@ -33,6 +34,7 @@ func (a *App) APIDocs(w http.ResponseWriter, r *http.Request) {
 			ShareXExampleURL:    a.cfg.BaseURL + "/api/v1/upload",
 			ShareXDownloadURL:   a.cfg.BaseURL + "/api/v1/sharex/warpbox-anonymous.sxcu",
 			ShareXFileFieldName: "sharex",
+			ShareXGroupWindow:   uploadGroupWindow.String(),
 		},
 	})
 }
@@ -47,11 +49,16 @@ func (a *App) ShareXAnonymousConfig(w http.ResponseWriter, r *http.Request) {
 		"RequestURL":      a.cfg.BaseURL + "/api/v1/upload",
 		"Headers": map[string]string{
 			"Accept": "application/json",
+			// Group a multi-file selection (sent as back-to-back requests) into
+			// one box. Remove this header for one box per file.
+			uploadBatchHeader: "sharex",
 		},
 		"Body":         "MultipartFormData",
 		"FileFormName": "sharex",
-		"URL":          "$json:boxUrl$",
-		"DeletionURL":  "$json:manageUrl$",
+		"URL":          "{json:boxUrl}",
+		"ThumbnailURL": "{json:thumbnailUrl}",
+		"DeletionURL":  "{json:deleteUrl}",
+		"ErrorMessage": "{json:error}",
 	})
 }
 
@@ -109,22 +116,24 @@ func (a *App) UploadResponseSchema(w http.ResponseWriter, r *http.Request) {
 		"type":        "object",
 		"required":    []string{"boxId", "boxUrl", "zipUrl", "manageUrl", "deleteUrl", "expiresAt", "files"},
 		"properties": map[string]any{
-			"boxId":     map[string]any{"type": "string"},
-			"boxUrl":    map[string]any{"type": "string", "format": "uri"},
-			"zipUrl":    map[string]any{"type": "string", "format": "uri"},
-			"manageUrl": map[string]any{"type": "string", "format": "uri", "description": "Private bearer URL for managing/deleting this upload. Returned only at upload time."},
-			"deleteUrl": map[string]any{"type": "string", "format": "uri", "description": "Private bearer POST URL for deleting this upload. Returned only at upload time."},
-			"expiresAt": map[string]any{"type": "string", "format": "date-time"},
+			"boxId":        map[string]any{"type": "string"},
+			"boxUrl":       map[string]any{"type": "string", "format": "uri"},
+			"zipUrl":       map[string]any{"type": "string", "format": "uri"},
+			"thumbnailUrl": map[string]any{"type": "string", "format": "uri", "description": "Thumbnail of the most recently uploaded file (placeholder until generated)."},
+			"manageUrl":    map[string]any{"type": "string", "format": "uri", "description": "Private bearer URL for managing/deleting this upload. Returned only at upload time."},
+			"deleteUrl":    map[string]any{"type": "string", "format": "uri", "description": "Private bearer URL for deleting this upload (GET or POST). Returned only at upload time."},
+			"expiresAt":    map[string]any{"type": "string", "format": "date-time"},
 			"files": map[string]any{
 				"type": "array",
 				"items": map[string]any{
 					"type":     "object",
 					"required": []string{"id", "name", "size", "url"},
 					"properties": map[string]any{
-						"id":   map[string]any{"type": "string"},
-						"name": map[string]any{"type": "string"},
-						"size": map[string]any{"type": "string"},
-						"url":  map[string]any{"type": "string", "format": "uri"},
+						"id":           map[string]any{"type": "string"},
+						"name":         map[string]any{"type": "string"},
+						"size":         map[string]any{"type": "string"},
+						"url":          map[string]any{"type": "string", "format": "uri"},
+						"thumbnailUrl": map[string]any{"type": "string", "format": "uri"},
 					},
 				},
 			},

backend/libs/handlers/app.go

@@ -18,6 +18,7 @@ type App struct {
 	settingsService *services.SettingsService
 	banService      *services.BanService
 	rateLimiter     *rateLimiter
+	uploadGroups    *uploadGrouper
 }
 
 func NewApp(cfg config.Config, logger *slog.Logger, renderer *web.Renderer, uploadService *services.UploadService, authService *services.AuthService, settingsService *services.SettingsService, banService *services.BanService) *App {
@@ -30,6 +31,7 @@ func NewApp(cfg config.Config, logger *slog.Logger, renderer *web.Renderer, uplo
 		settingsService: settingsService,
 		banService:      banService,
 		rateLimiter:     newRateLimiter(),
+		uploadGroups:    newUploadGrouper(),
 	}
 }
 
@@ -112,6 +114,9 @@ func (a *App) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("GET /d/{boxID}/deleted", a.ManageDeleted)
 	mux.HandleFunc("GET /d/{boxID}/manage/{token}", a.ManageBox)
 	mux.HandleFunc("POST /d/{boxID}/manage/{token}/delete", a.ManageDeleteBox)
+	// GET variant so ShareX (which issues a GET to the configured DeletionURL)
+	// can delete a box via its secret one-time delete token.
+	mux.HandleFunc("GET /d/{boxID}/manage/{token}/delete", a.ManageDeleteBox)
 	mux.HandleFunc("POST /d/{boxID}/unlock", a.UnlockBox)
 	mux.HandleFunc("GET /d/{boxID}/zip", a.DownloadZip)
 	mux.HandleFunc("GET /d/{boxID}/f/{fileID}", a.DownloadFile)

backend/libs/handlers/upload.go

@@ -92,7 +92,7 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		helpers.WriteJSONError(w, http.StatusRequestEntityTooLarge, fmt.Sprintf("expiration cannot exceed %d days", effectivePolicy.MaxDays))
 		return
 	}
-	result, err := a.uploadService.CreateBox(files, services.UploadOptions{
+	opts := services.UploadOptions{
 		MaxDays:           maxDays,
 		ExpiresInMinutes:  expiresMinutes,
 		MaxDownloads:      parseInt(r.FormValue("max_downloads")),
@@ -103,14 +103,15 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 		SkipSizeLimit:     isAdminUpload || effectivePolicy.MaxUploadMB < 0,
 		CreatorIP:         uploadClientIP(r),
 		StorageBackendID:  effectivePolicy.StorageBackendID,
-	})
+	}
+	result, boxesAdded, err := a.createOrAppendBox(r, user, loggedIn, files, opts)
 	if err != nil {
 		a.logger.Warn("upload failed", "source", "user-upload", "severity", "warn", "code", 4001, "ip", uploadClientIP(r), "user_id", user.ID, "error", err.Error())
 		helpers.WriteJSONError(w, http.StatusBadRequest, err.Error())
 		return
 	}
 	if !isAdminUpload {
-		if err := a.recordUploadUsage(r, user, loggedIn, totalBytes, 1); err != nil {
+		if err := a.recordUploadUsage(r, user, loggedIn, totalBytes, boxesAdded); err != nil {
 			a.logger.Warn("failed to record upload usage", "source", "quota", "severity", "warn", "code", 4402, "error", err.Error())
 		}
 		if err := a.settingsService.CleanupUsage(time.Now().UTC(), settings.UsageRetentionDays); err != nil {
@@ -130,6 +131,67 @@ func (a *App) Upload(w http.ResponseWriter, r *http.Request) {
 	_, _ = fmt.Fprintln(w, result.BoxURL)
 }
 
+// createOrAppendBox creates a new box. It only ever appends to an existing box
+// when the request opts in via the X-Warpbox-Batch header: requests sharing the
+// same batch value (per account, or per IP for anonymous) within
+// uploadGroupWindow are folded into one box. Without the header the behaviour is
+// identical to creating a fresh box every time. Returns the result and how many
+// boxes were created (1 for a new box, 0 for an append) for usage accounting.
+func (a *App) createOrAppendBox(r *http.Request, user services.User, loggedIn bool, files []*multipart.FileHeader, opts services.UploadOptions) (services.UploadResult, int, error) {
+	batch := strings.TrimSpace(r.Header.Get(uploadBatchHeader))
+	if batch == "" {
+		result, err := a.uploadService.CreateBox(files, opts)
+		if err != nil {
+			return services.UploadResult{}, 0, err
+		}
+		return result, 1, nil
+	}
+
+	// Group key is scoped to the uploader so batches never cross accounts/IPs.
+	identity := "ip:" + uploadClientIP(r)
+	if loggedIn {
+		identity = "user:" + user.ID
+	}
+	entry := a.uploadGroups.entryFor(identity + "|" + batch)
+
+	// Hold the per-key lock across the whole create/append so concurrent batched
+	// uploads serialise into the same box instead of racing.
+	entry.mu.Lock()
+	defer entry.mu.Unlock()
+
+	if entry.boxID != "" && time.Since(entry.at) < uploadGroupWindow {
+		if box, err := a.uploadService.GetBox(entry.boxID); err == nil && a.batchBoxMatches(box, user, loggedIn, r) && a.uploadService.CanDownload(box) == nil {
+			if result, err := a.uploadService.AppendFiles(entry.boxID, files, opts); err == nil {
+				// Re-attach the manage/delete URLs from the box's creation so every
+				// upload in the batch returns a working deletion URL.
+				result.ManageURL = entry.manageURL
+				result.DeleteURL = entry.deleteURL
+				entry.at = time.Now()
+				return result, 0, nil
+			}
+		}
+	}
+
+	result, err := a.uploadService.CreateBox(files, opts)
+	if err != nil {
+		return services.UploadResult{}, 0, err
+	}
+	entry.boxID = result.BoxID
+	entry.manageURL = result.ManageURL
+	entry.deleteURL = result.DeleteURL
+	entry.at = time.Now()
+	return result, 1, nil
+}
+
+// batchBoxMatches guards that a batched append only ever touches a box owned by
+// the same uploader (account for logged-in users, creator IP for anonymous).
+func (a *App) batchBoxMatches(box services.Box, user services.User, loggedIn bool, r *http.Request) bool {
+	if loggedIn {
+		return box.OwnerID == user.ID
+	}
+	return box.OwnerID == "" && box.CreatorIP == uploadClientIP(r)
+}
+
 func (a *App) checkUploadPolicy(r *http.Request, user services.User, loggedIn bool, settings services.UploadPolicySettings, policy services.EffectiveUploadPolicy, files []*multipart.FileHeader, totalBytes int64) (int, string) {
 	if len(files) == 0 {
 		return 0, ""

backend/libs/handlers/upload_group.go

@@ -0,0 +1,49 @@
+package handlers
+
+import (
+	"sync"
+	"time"
+)
+
+// uploadGroupWindow is how long after a batched upload a follow-up upload with
+// the same X-Warpbox-Batch value (and same account/IP) is folded into the same
+// box. ShareX sends a multi-file selection as separate back-to-back requests;
+// the batch header lets it land them in one box.
+const uploadGroupWindow = 20 * time.Second
+
+// uploadBatchHeader is the opt-in request header. Without it, uploads behave
+// exactly as before (one box per request). With it, requests sharing the same
+// value (per account/IP) within uploadGroupWindow are grouped into one box.
+const uploadBatchHeader = "X-Warpbox-Batch"
+
+// uploadGrouper tracks the most recent box per batch key so opt-in batched
+// uploads land in a single box. Each key has its own lock, which also serialises
+// that key's concurrent uploads so they append to the same box instead of racing
+// to create several.
+type uploadGrouper struct {
+	mu      sync.Mutex
+	entries map[string]*uploadGroupEntry
+}
+
+type uploadGroupEntry struct {
+	mu        sync.Mutex
+	boxID     string
+	manageURL string
+	deleteURL string
+	at        time.Time
+}
+
+func newUploadGrouper() *uploadGrouper {
+	return &uploadGrouper{entries: make(map[string]*uploadGroupEntry)}
+}
+
+func (g *uploadGrouper) entryFor(key string) *uploadGroupEntry {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	entry, ok := g.entries[key]
+	if !ok {
+		entry = &uploadGroupEntry{}
+		g.entries[key] = entry
+	}
+	return entry
+}

backend/libs/services/upload.go

@@ -82,20 +82,22 @@ type File struct {
 }
 
 type UploadResult struct {
-	BoxID     string       `json:"boxId"`
-	BoxURL    string       `json:"boxUrl"`
-	ZipURL    string       `json:"zipUrl"`
-	ManageURL string       `json:"manageUrl"`
-	DeleteURL string       `json:"deleteUrl"`
-	ExpiresAt string       `json:"expiresAt"`
-	Files     []ResultFile `json:"files"`
+	BoxID        string       `json:"boxId"`
+	BoxURL       string       `json:"boxUrl"`
+	ZipURL       string       `json:"zipUrl"`
+	ThumbnailURL string       `json:"thumbnailUrl"`
+	ManageURL    string       `json:"manageUrl"`
+	DeleteURL    string       `json:"deleteUrl"`
+	ExpiresAt    string       `json:"expiresAt"`
+	Files        []ResultFile `json:"files"`
 }
 
 type ResultFile struct {
-	ID   string `json:"id"`
-	Name string `json:"name"`
-	Size string `json:"size"`
-	URL  string `json:"url"`
+	ID           string `json:"id"`
+	Name         string `json:"name"`
+	Size         string `json:"size"`
+	URL          string `json:"url"`
+	ThumbnailURL string `json:"thumbnailUrl"`
 }
 
 type AdminStats struct {
@@ -226,15 +228,66 @@ func (s *UploadService) CreateBox(files []*multipart.FileHeader, opts UploadOpti
 		box.PasswordHash = hash
 	}
 
-	backend, err := s.storage.Backend(box.StorageBackendID)
+	if err := s.writeFilesToBox(&box, files, opts); err != nil {
+		return UploadResult{}, err
+	}
+
+	if err := s.SaveBox(box); err != nil {
+		return UploadResult{}, err
+	}
+
+	s.logger.Info("upload complete",
+		"source", "user-upload",
+		"severity", "user_activity",
+		"code", 2001,
+		"box_id", box.ID,
+		"file_count", len(box.Files),
+	)
+
+	return s.resultForBox(box, deleteToken), nil
+}
+
+// AppendFiles adds files to an existing box (used to group a ShareX multi-file
+// selection into a single box). The box keeps its original expiry, password and
+// other settings; only the new files are written.
+func (s *UploadService) AppendFiles(boxID string, files []*multipart.FileHeader, opts UploadOptions) (UploadResult, error) {
+	if len(files) == 0 {
+		return UploadResult{}, fmt.Errorf("no files were uploaded")
+	}
+	box, err := s.GetBox(boxID)
 	if err != nil {
 		return UploadResult{}, err
 	}
+	if err := s.writeFilesToBox(&box, files, opts); err != nil {
+		return UploadResult{}, err
+	}
+	if err := s.SaveBox(box); err != nil {
+		return UploadResult{}, err
+	}
+	s.logger.Info("upload appended",
+		"source", "user-upload",
+		"severity", "user_activity",
+		"code", 2001,
+		"box_id", box.ID,
+		"added", len(files),
+		"file_count", len(box.Files),
+	)
+	return s.resultForBox(box, ""), nil
+}
+
+// writeFilesToBox streams each uploaded file into the box's storage backend and
+// appends the file metadata to box.Files. The box's StorageBackendID determines
+// where files land, so it works for both new and existing boxes.
+func (s *UploadService) writeFilesToBox(box *Box, files []*multipart.FileHeader, opts UploadOptions) error {
+	backend, err := s.storage.Backend(box.StorageBackendID)
+	if err != nil {
+		return err
+	}
 
 	for _, header := range files {
 		if !opts.SkipSizeLimit {
 			if err := s.ValidateSize(header.Size); err != nil {
-				return UploadResult{}, err
+				return err
 			}
 		}
 
@@ -245,7 +298,7 @@ func (s *UploadService) CreateBox(files []*multipart.FileHeader, opts UploadOpti
 
 		file, err := header.Open()
 		if err != nil {
-			return UploadResult{}, err
+			return err
 		}
 
 		fileID := randomID(8)
@@ -263,7 +316,7 @@ func (s *UploadService) CreateBox(files []*multipart.FileHeader, opts UploadOpti
 
 		if err := s.writeUploadedObject(context.Background(), backend, objectKey, file, header.Size, maxSize, contentType); err != nil {
 			file.Close()
-			return UploadResult{}, err
+			return err
 		}
 		file.Close()
 
@@ -278,20 +331,7 @@ func (s *UploadService) CreateBox(files []*multipart.FileHeader, opts UploadOpti
 			UploadedAt:  time.Now().UTC(),
 		})
 	}
-
-	if err := s.SaveBox(box); err != nil {
-		return UploadResult{}, err
-	}
-
-	s.logger.Info("upload complete",
-		"source", "user-upload",
-		"severity", "user_activity",
-		"code", 2001,
-		"box_id", box.ID,
-		"file_count", len(box.Files),
-	)
-
-	return s.resultForBox(box, deleteToken), nil
+	return nil
 }
 
 func (s *UploadService) GetBox(id string) (Box, error) {
@@ -726,19 +766,28 @@ func (s *UploadService) resultForBox(box Box, deleteToken string) UploadResult {
 	files := make([]ResultFile, 0, len(box.Files))
 	for _, file := range box.Files {
 		files = append(files, ResultFile{
-			ID:   file.ID,
-			Name: file.Name,
-			Size: helpers.FormatBytes(file.Size),
-			URL:  fmt.Sprintf("%s/d/%s/f/%s", s.baseURL, box.ID, file.ID),
+			ID:           file.ID,
+			Name:         file.Name,
+			Size:         helpers.FormatBytes(file.Size),
+			URL:          fmt.Sprintf("%s/d/%s/f/%s", s.baseURL, box.ID, file.ID),
+			ThumbnailURL: fmt.Sprintf("%s/d/%s/thumb/%s", s.baseURL, box.ID, file.ID),
 		})
 	}
 
+	// The box-level thumbnail points at the most recently added file, so a
+	// per-file ShareX upload previews the file it just sent.
+	thumbnailURL := fmt.Sprintf("%s/d/%s/og-image.jpg", s.baseURL, box.ID)
+	if len(files) > 0 {
+		thumbnailURL = files[len(files)-1].ThumbnailURL
+	}
+
 	result := UploadResult{
-		BoxID:     box.ID,
-		BoxURL:    fmt.Sprintf("%s/d/%s", s.baseURL, box.ID),
-		ZipURL:    fmt.Sprintf("%s/d/%s/zip", s.baseURL, box.ID),
-		ExpiresAt: box.ExpiresAt.Format(time.RFC3339),
-		Files:     files,
+		BoxID:        box.ID,
+		BoxURL:       fmt.Sprintf("%s/d/%s", s.baseURL, box.ID),
+		ZipURL:       fmt.Sprintf("%s/d/%s/zip", s.baseURL, box.ID),
+		ThumbnailURL: thumbnailURL,
+		ExpiresAt:    box.ExpiresAt.Format(time.RFC3339),
+		Files:        files,
 	}
 	if deleteToken != "" {
 		result.ManageURL = fmt.Sprintf("%s/d/%s/manage/%s", s.baseURL, box.ID, deleteToken)

backend/static/css/40-docs.css

@@ -36,6 +36,22 @@
   font-size: 1rem;
 }
 
+.docs-card h3 {
+  margin: 1.35rem 0 0;
+  font-size: 0.9rem;
+  font-weight: 650;
+  color: var(--foreground);
+}
+
+/* Highlights where the API token goes in the ShareX config snippet. */
+.sxcu-highlight {
+  background: #fde047;
+  color: #1a1a1a;
+  font-weight: 700;
+  padding: 0 0.2rem;
+  border-radius: 3px;
+}
+
 .docs-card p {
   margin: 0.65rem 0 0;
   color: var(--muted-foreground);

backend/templates/layouts/base.html

@@ -60,7 +60,7 @@
   </main>
 
   <footer class="site-footer">
-    <span>{{.AppName}} · {{.AppVersion}} · {{.CurrentYear}} · self-hosted</span>
+    <span>{{.AppName}} · {{.AppVersion}} · {{.CurrentYear}}</span>
     <label class="theme-picker">
       <span>Theme</span>
       <select data-theme-select aria-label="Site theme">

backend/templates/pages/api.html

@@ -36,11 +36,12 @@
     <article class="card docs-card">
       <div class="card-content">
         <h2>JSON response</h2>
-        <p>The raw delete token is returned only once inside <code>manageUrl</code> and <code>deleteUrl</code>. Keep those links private.</p>
+        <p>The raw delete token is returned only once inside <code>manageUrl</code> and <code>deleteUrl</code>. Keep those links private. On error the body is <code>{ "error": "message" }</code> with a non-2xx status (e.g. rate limited or over a limit).</p>
         <pre><code>{
   "boxId": "abc123",
   "boxUrl": "{{.Data.BaseURL}}/d/abc123",
   "zipUrl": "{{.Data.BaseURL}}/d/abc123/zip",
+  "thumbnailUrl": "{{.Data.BaseURL}}/d/abc123/thumb/file123",
   "manageUrl": "{{.Data.BaseURL}}/d/abc123/manage/private-token",
   "deleteUrl": "{{.Data.BaseURL}}/d/abc123/manage/private-token/delete",
   "expiresAt": "2026-06-05T12:00:00Z",
@@ -49,7 +50,8 @@
       "id": "file123",
       "name": "report.pdf",
       "size": "2.4 MiB",
-      "url": "{{.Data.BaseURL}}/d/abc123/f/file123"
+      "url": "{{.Data.BaseURL}}/d/abc123/f/file123",
+      "thumbnailUrl": "{{.Data.BaseURL}}/d/abc123/thumb/file123"
     }
   ]
 }</code></pre>
@@ -59,22 +61,44 @@
     <article class="card docs-card">
       <div class="card-content">
         <h2>ShareX setup</h2>
+        <p>Import the uploader, then add your API key to upload as your account — with your account's size, daily, and retention limits — instead of as an anonymous guest.</p>
+
+        <h3>1 · Import the uploader</h3>
         <ol class="docs-steps">
-          <li>Download the instance config: <a href="/api/v1/sharex/warpbox-anonymous.sxcu"><code>/api/v1/sharex/warpbox-anonymous.sxcu</code></a>.</li>
-          <li>Or open the tracked template at <code>{{.Data.ShareXExamplePath}}</code> and change <code>RequestURL</code> to <code>{{.Data.ShareXExampleURL}}</code>.</li>
-          <li>Keep <code>FileFormName</code> as <code>{{.Data.ShareXFileFieldName}}</code>.</li>
-          <li>Import the <code>.sxcu</code> file into ShareX as a custom uploader.</li>
-          <li>Upload a file. ShareX will use <code>boxUrl</code> as the public URL and <code>manageUrl</code> as the deletion URL.</li>
+          <li>Download <a href="/api/v1/sharex/warpbox-anonymous.sxcu"><code>warpbox-anonymous.sxcu</code></a>.</li>
+          <li>In ShareX: <code>Destinations → Custom uploader settings → Import → From file</code>, then pick the <code>.sxcu</code>.</li>
         </ol>
+
+        <h3>2 · Add your API key (upload as your account)</h3>
+        <ol class="docs-steps">
+          <li>Create a personal access token under <a href="/account/settings">Account → Access tokens</a> and copy it.</li>
+          <li>In <code>Custom uploader settings</code>, select the Warpbox uploader and open the <code>Headers</code> section.</li>
+          <li>Add a header — Name <code>Authorization</code>, Value <code>Bearer &lt;your token&gt;</code>.</li>
+        </ol>
+        <p class="muted-copy">Without that header, uploads stay anonymous. With it, they're attributed to your account and use your account's limits.</p>
+
         <pre><code>{
+  "Version": "1.0.0",
+  "Name": "Warpbox (my account)",
+  "DestinationType": "ImageUploader, FileUploader, TextUploader",
   "RequestMethod": "POST",
   "RequestURL": "{{.Data.ShareXExampleURL}}",
-  "Headers": { "Accept": "application/json" },
+  "Headers": {
+    "Accept": "application/json",
+    "Authorization": "Bearer <span class="sxcu-highlight">YOUR_API_TOKEN</span>",
+    "X-Warpbox-Batch": "sharex"
+  },
   "Body": "MultipartFormData",
   "FileFormName": "{{.Data.ShareXFileFieldName}}",
-  "URL": "$json:boxUrl$",
-  "DeletionURL": "$json:manageUrl$"
+  "URL": "{json:boxUrl}",
+  "ThumbnailURL": "{json:thumbnailUrl}",
+  "DeletionURL": "{json:deleteUrl}",
+  "ErrorMessage": "{json:error}"
 }</code></pre>
+
+        <h3>Grouping multiple files into one box</h3>
+        <p>Grouping is <strong>opt-in via the <code>X-Warpbox-Batch</code> request header</strong> — without it, every file becomes its own box (the default). When the header is present, uploads sharing the same value (per account, or per IP for anonymous) within {{.Data.ShareXGroupWindow}} of each other are added to the <strong>same</strong> box, so a multi-file ShareX selection produces one shareable link instead of one per file. The shipped config sets <code>X-Warpbox-Batch: sharex</code>; remove that header for one box per file.</p>
+        <p class="muted-copy">The response also exposes <code>{json:thumbnailUrl}</code> for ShareX previews, <code>{json:deleteUrl}</code> for the deletion URL, and <code>{json:error}</code> so ShareX surfaces messages like rate limiting.</p>
       </div>
     </article>