Designing with Sleek

Overview

sleek.design is an AI-powered mobile app design tool. You interact with it via a REST API at /api/v1/* to create projects, describe what you want built in plain language, and get back rendered screens. All communication is standard HTTP with bearer token auth. Base URL: https://sleek.design Auth: Authorization: Bearer $SLEEK_API_KEY on every /api/v1/* request Content-Type: application/json (requests and responses) CORS: Enabled on all /api/v1/* endpoints

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Prerequisites: API Key

Create API keys at https://sleek.design/dashboard/api-keys. The full key value is shown only once at creation — store it in the SLEEK_API_KEY environment variable. Required plan: Pro+ (API access is gated)

Key scopes

Scope What it unlocks projects:read List / get projects projects:write Create / delete projects components:read List components in a project chats:read Get chat run status chats:write Send chat messages screenshots Render component screenshots Create a key with only the scopes needed for the task.

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Security & Privacy

• Single host: All requests go exclusively to https://sleek.design. No data is sent to third parties.
• HTTPS only: All communication uses HTTPS. The API key is transmitted only in the Authorization header to Sleek endpoints.
• Minimal scopes: Create API keys with only the scopes required for the task. Prefer short-lived or revocable keys.
• Image URLs: When using imageUrls in chat messages, those URLs are fetched by Sleek's servers. Avoid passing URLs that contain sensitive content.

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Handling high-level requests

When the user says something like "design a fitness tracking app" or "build me a settings screen":

1. Create a project if one doesn't exist yet (ask the user for a name, or derive one from the request)
2. Send a chat message describing what to build — you can use the user's words directly as message.text; Sleek's AI interprets natural language
3. Follow the screenshot delivery rule below to show the result You do not need to decompose the request into screens first. Send the full intent as a single message and let Sleek decide what screens to create.

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Screenshot delivery rule

After every chat run that produces screen_created or screen_updated operations, always take screenshots and show them to the user. Never silently complete a chat run without delivering the visuals. When screens are created for the first time on a project (i.e. the run includes screen_created operations), deliver:

1. One screenshot per newly created screen (individual componentIds: [screenId])
2. One combined screenshot of all screens in the project (componentIds: [all screen ids]) When only existing screens are updated, deliver one screenshot per affected screen. Use background: "transparent" for all screenshots unless the user explicitly requests otherwise.

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Quick Reference — All Endpoints

Method Path Scope Description GET /api/v1/projects projects:read List projects POST /api/v1/projects projects:write Create project GET /api/v1/projects/:id projects:read Get project DELETE /api/v1/projects/:id projects:write Delete project GET /api/v1/projects/:id/components components:read List components POST /api/v1/projects/:id/chat/messages chats:write Send chat message GET /api/v1/projects/:id/chat/runs/:runId chats:read Poll run status POST /api/v1/screenshots screenshots Render screenshot All IDs are stable string identifiers.

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Endpoints

Projects

List projects

GET /api/v1/projects?limit=50&offset=0
Authorization: Bearer $SLEEK_API_KEY

Response 200:

{
  "data": [
    {
      "id": "proj_abc",
      "name": "My App",
      "slug": "my-app",
      "createdAt": "2026-01-01T00:00:00Z",
      "updatedAt": "..."
    }
  ],
  "pagination": { "total": 12, "limit": 50, "offset": 0 }
}

Create project

POST /api/v1/projects
Authorization: Bearer $SLEEK_API_KEY
Content-Type: application/json
{ "name": "My New App" }

Response 201 — same shape as a single project.

Get / Delete project

GET    /api/v1/projects/:projectId
DELETE /api/v1/projects/:projectId   → 204 No Content

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Components

List components

GET /api/v1/projects/:projectId/components?limit=50&offset=0
Authorization: Bearer $SLEEK_API_KEY

Response 200:

{
  "data": [
    {
      "id": "cmp_xyz",
      "name": "Hero Section",
      "activeVersion": 3,
      "versions": [{ "id": "ver_001", "version": 1, "createdAt": "..." }],
      "createdAt": "...",
      "updatedAt": "..."
    }
  ],
  "pagination": { "total": 5, "limit": 50, "offset": 0 }
}

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Chat — Send Message

This is the core action: describe what you want in message.text and the AI creates or modifies screens.

POST /api/v1/projects/:projectId/chat/messages?wait=false
Authorization: Bearer $SLEEK_API_KEY
Content-Type: application/json
idempotency-key: <optional, max 255 chars>
{
  "message": { "text": "Add a pricing section with three tiers" },
  "imageUrls": ["https://example.com/ref.png"],
  "target": { "screenId": "scr_abc" }
}

Field Required Notes message.text Yes 1+ chars, trimmed imageUrls No HTTPS URLs only; included as visual context target.screenId No Edit a specific screen; omit to let AI decide ?wait=true/false No Sync wait mode (default: false) idempotency-key header No Replay-safe re-sends

Response — async (default, wait=false)

Status 202 Accepted. result and error are absent until the run reaches a terminal state.

{
  "data": {
    "runId": "run_111",
    "status": "queued",
    "statusUrl": "/api/v1/projects/proj_abc/chat/runs/run_111"
  }
}

Response — sync (wait=true)

Blocks up to 300 seconds. Returns 200 when completed, 202 if timed out.

{
  "data": {
    "runId": "run_111",
    "status": "completed",
    "statusUrl": "...",
    "result": {
      "assistantText": "I added a pricing section with...",
      "operations": [
        { "type": "screen_created", "screenId": "scr_xyz", "screenName": "Pricing" },
        { "type": "screen_updated", "screenId": "scr_abc" },
        { "type": "theme_updated" }
      ]
    }
  }
}

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Chat — Poll Run Status

Use this after async send to check progress.

GET /api/v1/projects/:projectId/chat/runs/:runId
Authorization: Bearer $SLEEK_API_KEY

Response — same shape as send message data object:

{
  "data": {
    "runId": "run_111",
    "status": "queued",
    "statusUrl": "..."
  }
}

When completed successfully, result is present:

{
  "data": {
    "runId": "run_111",
    "status": "completed",
    "statusUrl": "...",
    "result": {
      "assistantText": "...",
      "operations": [...]
    }
  }
}

When failed, error is present:

{
  "data": {
    "runId": "run_111",
    "status": "failed",
    "statusUrl": "...",
    "error": { "code": "execution_failed", "message": "..." }
  }
}

Run status lifecycle: queued → running → completed | failed

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Screenshots

Takes a snapshot of one or more rendered components.

POST /api/v1/screenshots
Authorization: Bearer $SLEEK_API_KEY
Content-Type: application/json
{
  "componentIds": ["cmp_xyz", "cmp_abc"],
  "projectId": "proj_abc",
  "format": "png",
  "scale": 2,
  "gap": 40,
  "padding": 40,
  "background": "transparent"
}

Field Default Notes format png png or webp scale 2 1–3 (device pixel ratio) gap 40 Pixels between components padding 40 Uniform padding on all sides paddingX (optional) Horizontal padding; overrides padding for left/right when provided paddingY (optional) Vertical padding; overrides padding for top/bottom when provided paddingTop (optional) Top padding; overrides paddingY when provided paddingRight (optional) Right padding; overrides paddingX when provided paddingBottom (optional) Bottom padding; overrides paddingY when provided paddingLeft (optional) Left padding; overrides paddingX when provided background transparent Any CSS color (hex, named, transparent) showDots false Overlay a subtle dot grid on the background Padding resolves with a cascade: per-side → axis → uniform. For example, paddingTop falls back to paddingY, which falls back to padding. So { "padding": 20, "paddingX": 10, "paddingLeft": 5 } gives top/bottom 20px, right 10px, left 5px. When showDots is true, a dot pattern is drawn over the background color. The dots automatically adapt to the background: dark backgrounds get light dots, light backgrounds get dark dots. This has no effect when background is "transparent". Always use "background": "transparent" unless the user explicitly requests a specific background color. Response: raw binary image/png or image/webp with Content-Disposition: attachment.

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Error Shapes

{ "code": "UNAUTHORIZED", "message": "..." }

HTTP Code When 401 UNAUTHORIZED Missing/invalid/expired API key 403 FORBIDDEN Valid key, wrong scope or plan 404 NOT_FOUND Resource doesn't exist 400 BAD_REQUEST Validation failure 409 CONFLICT Another run is active for this project 500 INTERNAL_SERVER_ERROR Server error Chat run-level errors (inside data.error): Code Meaning out_of_credits Organization has no credits left execution_failed AI execution error

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Flows

Flow 1: Create project and generate a UI (async + polling)

1. POST /api/v1/projects                              → get projectId
2. POST /api/v1/projects/:id/chat/messages            → get runId (202)
3. Poll GET /api/v1/projects/:id/chat/runs/:runId
   until status == "completed" or "failed"
4. Collect screenIds from result.operations
   (screen_created and screen_updated entries)
5. Screenshot each affected screen individually
6. If any screen_created: also screenshot all project screens combined
7. Show all screenshots to the user

Polling recommendation: start at 2s interval, back off to 5s after 10s, give up after 5 minutes.

Flow 2: Sync mode (simple, blocking)

Best for short tasks or when latency is acceptable.

1. POST /api/v1/projects/:id/chat/messages?wait=true
   → blocks up to 300s
   → 200 if completed, 202 if timed out
2. If 202, fall back to Flow 1 polling with the returned runId
3. On completion, screenshot and show affected screens (see screenshot delivery rule)

Flow 3: Edit a specific screen

1. GET /api/v1/projects/:id/components         → find screenId
2. POST /api/v1/projects/:id/chat/messages
   body: { message: { text: "..." }, target: { screenId: "scr_xyz" } }
3. Poll or wait as above
4. Screenshot the updated screen and show it to the user

Flow 4: Idempotent message (safe retries)

Add idempotency-key header on the send request. If the network drops and you retry with the same key, the server returns the existing run rather than creating a duplicate. The key must be ≤255 chars.

POST /api/v1/projects/:id/chat/messages
idempotency-key: my-unique-request-id-abc123

Flow 5: One run at a time (conflict handling)

Only one active run is allowed per project. If you send a message while one is running, you get 409 CONFLICT. Wait for the active run to complete before sending the next message.

409 response → poll existing run → completed → send next message

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Pagination

All list endpoints accept limit (1–100, default 50) and offset (≥0). The response always includes pagination.total so you can page through all results.

GET /api/v1/projects?limit=10&offset=20

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Common Mistakes

Mistake Fix Sending to /api/v1 without Authorization header Add Authorization: Bearer $SLEEK_API_KEY to every request Using wrong scope Check key's scopes match the endpoint (e.g. chats:write for sending messages) Sending next message before run completes Poll until completed/failed before next send Using wait=true on long generations It blocks 300s max; have a fallback to polling for 202 response HTTP URLs in imageUrls Only HTTPS URLs are accepted Assuming result is present on 202 result is absent until status is completed

GitHub Owner

Owner: sleekdotdesign

GitHub Links

• Website: https://sleek.design
• Instagram: https://www.instagram.com/sleek_labs