Last updated · 26 October 2026

SVG Lab API

SVG Lab's Design Engine over plain HTTP, for agents and scripts: start a project, run Design Engine operations in it, generate SVG with AI Generate, place placeholder photos, and download the finished SVG, PNG, PDF or code.

Use when the task needs a real, editable vector file (logo, icon set, app screen, social graphic) rather than an SVG string pasted into chat. Every project opens in the SVG Lab editor, so a person can keep working on it.

The API is in early access. To get keys, write to support@svglab.app.

Keys

Create a key on your Account page, under API keys. It belongs to your workspace, is shown once, and goes in every request as Authorization: Bearer <key>.
svl_live_ keys use the workspace's SVG Lab credits: 1 credit a Design Engine call, AI Generate 500 (700 on business plans). A call that fails costs nothing.
test_ keys are the sandbox: 1,000 test credits a month per workspace, the real operations, watermarked SVG and PNG, and no AI Generate, PDF or code.
Every key has a daily credit cap you set. Revoking a key stops it on its next call.

One full example

Start a project, draw in it, take the SVG:

curl -s https://svglab.app/api/v1/projects \
  -H "Authorization: Bearer $SVGLAB_KEY" -H "Content-Type: application/json" \
  -H "Idempotency-Key: coffee-1" \
  -d '{"name": "Coffee shop badge"}'

{"ok": true, "project": {"id": "3f6c2a7e-8b1d-4c55-9a0e-2d7b8f1e4c90",
  "name": "Coffee shop badge", "url": "https://svglab.app/?project=3f6c2a7e-8b1d-4c55-9a0e-2d7b8f1e4c90"},
  "credits": 1, "job": {"id": "b2e4...", "status": "succeeded"}}

curl -s https://svglab.app/api/v1/projects/3f6c2a7e-8b1d-4c55-9a0e-2d7b8f1e4c90/run \
  -H "Authorization: Bearer $SVGLAB_KEY" -H "Content-Type: application/json" \
  -d '{"ops": [
        {"op": "add_artboard", "args": {"name": "Badge", "width": 512, "height": 512}},
        {"op": "create_shapes", "args": {"artboard": "Badge", "shapes": [
          {"type": "shape", "kind": "ellipse", "x": 56, "y": 56, "width": 400, "height": 400, "style": {"fill": "#3B2418"}},
          {"type": "text", "content": "BREW", "x": 256, "y": 270, "font_family": "Fraunces", "font_size": 96, "style": {"fill": "#F3E3C7"}}]}}]}'

{"ok": true, "result": [{"ok": true, "name": "Badge"}, {"ok": true, "shape_ids": ["s4", "s5"]}],
  "created_ids": ["s4", "s5"], "warnings": [], "credits": 1}

curl -s "https://svglab.app/api/v1/projects/3f6c2a7e-8b1d-4c55-9a0e-2d7b8f1e4c90/export?format=svg&artboard=Badge" \
  -H "Authorization: Bearer $SVGLAB_KEY" -o badge.svg

run also takes code: JavaScript that calls await sl.op(name, args), so one call can build a whole screen. GET /api/v1/ops lists the operations and GET /api/v1/ops/{name} gives one's arguments.

Routes

Route	Does
`POST /projects`, `GET /projects`, `GET /projects/{id}`	Start, list, describe (listing is free)
`POST /projects/{id}/run`	Design Engine operations: `ops` or `code`
`POST /projects/{id}/look`	The render with measured problems (overflow, overlap, contrast)
`POST /generate`	AI Generate: a sentence or a picture in, SVG code out, marked as AI-generated in the file; optionally placed in a project
`POST /projects/{id}/photos`	A free placeholder photo by description, cropped into a box, with the photographer's credit kept in the file
`GET /projects/{id}/export?format=svg\|png\|pdf\|code`	The finished file
`GET /jobs/{id}`, `GET /usage`, `GET /guides/{topic}`	Jobs, receipts, the design guides

The OpenAPI 3.1 document has every field, generated from the same catalog the SVG Lab MCP serves.

Long runs, retries and limits

AI Generate takes 1 to 3 minutes. Send "async": true for a 202 and a job, then poll GET /api/v1/jobs/{id}, or add webhook_url. Webhooks carry SVGLab-Signature: t=<unix>,v1=<hex>, the HMAC-SHA256 of t + "." + body with the key's webhook secret.
Send Idempotency-Key on every POST you might retry: a repeat returns the first answer and is never billed twice.
About 120 calls a minute and 8 at once per workspace. A refusal carries retry_after_s.

Partners

A partner key serves your own customers: send SVGLab-End-Customer: <your id for them> on every call, never an email address. Each end customer has its own daily cap, sees only its own projects and jobs, and can be paused on your Account page without pausing you. Receipts name the end customer.

Errors

Every error is {"ok": false, "error", "message", "fix"}, and fix says what to change.

error	What to change
`missing_key`, `invalid_key`, `key_revoked` (401)	Send a current key as `Authorization: Bearer`; make one on your Account page.
`missing_scope`, `account_suspended`, `team_workspace_not_ready`	Use a key with the scope named; write to support; use a personal workspace key.
`credits_needed` (402)	Add credits on Billing.
`key_daily_cap`, `end_customer_daily_cap`, `sandbox_credits_used_up`, `rate_limited` (429)	Wait until `resets_at`, raise the cap, or use a live key.
`sandbox_no_ai_generate`, `sandbox_export_format`	Use a live key.
`end_customer_id_required`, `end_customer_id_email`, `end_customer_id_invalid`, `end_customer_not_partner`, `end_customer_suspended`	Partner keys only: your own id (letters, digits, `. _ : -`); the partner can resume a paused customer.
`bad_request`, `invalid_json`, `payload_too_large`, `webhook_url_invalid`, `idempotency_key_invalid`	Fix the field the message names (JSON, under 16 MB, a public https webhook).
`project_not_found`, `job_not_found`, `not_found`	Use an id this key made or can see; check the path in the OpenAPI document.
`operation_failed` (422)	The message names what to change in the operation.
`idempotency_in_progress`, `idempotency_key_reused`	Poll the job; use a new key for a new request.
`editor_starting`, `still_running`	Send it again after `retry_after_s`; check the project before repeating a long call.
`export_failed`, `ai_generate_failed`, `ai_generate_unavailable`, `limiter_unavailable`, `credits_unavailable`, `api_not_ready`, `unavailable`	Nothing was charged: try again in a minute.

Rules

The terms apply. Never present AI Generate output as made by a person, and never use the API for harmful content. Questions: support@svglab.app.