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

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.

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.

Handling high-level requests

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

Create a project if one doesn't exist yet (ask the user for a name, or derive one from the request)
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
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.

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:

One screenshot per newly created screen (individual
```
componentIds: [screenId]
```
)
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.

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.

Endpoints

Projects

List projects

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

Response

{
  "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

— same shape as a single project.

Get / Delete project

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

Components

List components

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

Response

{
  "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 }
}

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

when completed,

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" }
      ]
    }
  }
}

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

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

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

"transparent"

Always use

"background": "transparent"

unless the user explicitly requests a specific background color.

Response: raw binary

image/png

image/webp

with

Content-Disposition: attachment

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

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

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

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`

Desing mobile apps

AI Skill Market Insights

Be Part of the 0+ Developer Community

Designing with Sleek

Overview

Prerequisites: API Key

Key scopes

Security & Privacy

Handling high-level requests

Screenshot delivery rule

Quick Reference — All Endpoints

Endpoints

Projects

List projects

Create project

Get / Delete project

Components

List components

Chat — Send Message

Response — async (default, wait=false)

Response — sync (wait=true)

Chat — Poll Run Status

Screenshots

Error Shapes

Flows

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

Flow 2: Sync mode (simple, blocking)

Flow 3: Edit a specific screen

Flow 4: Idempotent message (safe retries)

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

Pagination

Common Mistakes

Quick Start

Manual Installation

TEAR & SHARE

Tags

Channels

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Response — async (default,
`wait=false`
)

Response — sync (
`wait=true`
)