REST API

The API server runs on port 1349 by default and serves all endpoints under /api.

Full API Reference

When your Stirling Image instance is running, visit /api/docs for the complete interactive API reference with all 67 endpoints, request/response schemas, and examples.

LLM-friendly docs

Need to feed these docs to an AI assistant? Use /llms.txt for an index or /llms-full.txt for the complete documentation in a single file. On a running instance, these are also available at /llms.txt and /llms-full.txt.

This page covers the basics of using the API. For per-endpoint details (every parameter, schema, and response), see the interactive docs at /api/docs.

Authentication

Two methods:

1. Session token -- POST /api/auth/login with { "username", "password" }. Returns a token. Pass as Authorization: Bearer <token>.
2. API key -- Generate via Settings UI or POST /api/v1/api-keys. Prefixed with si_. Pass as Authorization: Bearer si_....

Public endpoints (no auth required): health check, login, API docs, downloads, job progress.

Using a tool

Every tool follows the same pattern:

POST /api/v1/tools/:toolId
Content-Type: multipart/form-data

Send a multipart request with:

• file -- the image
• settings -- JSON string with tool-specific options

{
  "jobId": "abc123",
  "downloadUrl": "/api/v1/download/abc123/output.png",
  "originalSize": 245000,
  "processedSize": 180000
}

Tool IDs

Category	Tools
Essentials	resize, crop, rotate, convert, compress
Optimization	strip-metadata, bulk-rename, image-to-pdf, favicon
Adjustments	brightness-contrast, saturation, color-channels, color-effects, replace-color
AI	remove-background, upscale, erase-object, ocr, blur-faces, smart-crop
Watermark	watermark-text, watermark-image, text-overlay, compose
Utilities	info, compare, find-duplicates, color-palette, qr-generate, barcode-read
Layout	collage, split, border
Format	svg-to-raster, vectorize, gif-tools

Each tool's specific settings are documented in the interactive API reference.

Batch processing

POST /api/v1/tools/:toolId/batch

Send multiple files with the same settings. Returns a ZIP. Use the X-Job-Id header to track progress.

Pipelines

Chain tools into reusable workflows.

POST /api/v1/pipeline/execute   -- Run a pipeline (multipart: file + steps JSON)
POST /api/v1/pipeline/save      -- Save a named pipeline
GET  /api/v1/pipeline/list      -- List saved pipelines
DELETE /api/v1/pipeline/:id     -- Delete a pipeline

Example steps:

[
  { "toolId": "resize", "settings": { "width": 200, "height": 200, "fit": "cover" } },
  { "toolId": "compress", "settings": { "quality": 80 } },
  { "toolId": "convert", "settings": { "format": "webp" } }
]

Progress tracking (SSE)

For long-running jobs (AI tools, batch processing):

GET /api/v1/jobs/:jobId/progress

Returns a Server-Sent Events stream with { status, progress, completedFiles, failedFiles }.

Error responses

{ "statusCode": 400, "error": "Bad Request", "message": "Invalid image format" }

Status codes: 400 invalid input, 401 not authenticated, 403 not authorized, 413 file too large, 429 rate limited, 500 server error.