design-mobile-apps

---
name: design-mobile-apps
description: Design mobile app screens with Sleek, edit Sleek projects, and implement their designs in React Native or HTML.
metadata:
  requires-env: SLEEK_API_KEY
---

# Designing with Sleek

[![Design mobile apps in minutes](https://raw.githubusercontent.com/sleekdotdesign/agent-skills/main/assets/hero.png)](https://sleek.design)

## Overview

[sleek.design](https://sleek.design) provides a REST API at `/api/v1/*` to create projects, design screens from a brief, and fetch their HTML and renders.

**Base URL**: `https://sleek.design`
**Auth**: `Authorization: Bearer $SLEEK_API_KEY`, except the public device start/poll endpoints
**Content-Type**: send `application/json` for JSON request bodies.
**CORS**: Enabled on all `/api/v1/*` endpoints
**Envelope**: check HTTP status first. Successful JSON wraps its payload in `data`; lists also include sibling `pagination`. Errors use top-level `code`, `status` and `message`, with optional `data.url`. Successful screenshots and share cards return image bytes; `204` has no body.
**Ids**: opaque 11-character tokens like `V1StGXR8Z5j`, with no type prefix. Nothing about an id says whether it names a project, screen, component, version or theme, so track each one by the response field it arrived in.
**Parsing responses**: write the body to a file (`curl -o run.json`) and parse the file. Piping JSON through `echo` corrupts it: zsh expands the escaped `\n` inside string values into real newlines, which makes the body invalid JSON.
**API docs**: OpenAPI spec at `https://sleek.design/api/v1/spec.json`; browsable docs at `https://sleek.design/api/v1/docs`. Fetch the spec for any contract detail not covered here.

---

## Designing or implementing

A single run can take both directions — "design me a fitness app and build it in Expo" is a design pass followed by an implementation pass. Gate each pointer on the artefact in front of you rather than on a one-time reading of the request:

**Designing** — you are about to send a chat message to Sleek. Read [designing.md](designing.md) first; it carries the create → chat → screenshot loop, how to author a style direction, and when to seed one from a reference instead.

**Implementing.** Before writing code from a Sleek design, read [implementing.md](implementing.md) for version selection, native conversion, working features, and acceptance checks.

## User shot and review shot

Screenshots come in two framings, and each file below asks for one by name:

- A **user shot** is the default render: viewport height, phone-shaped. This is the one you show the user.
- A **review shot** adds `fullHeight: true`, one component per request. This is the one you judge your own work against.

---

## Prerequisites: API Key

If `SLEEK_API_KEY` is not set, use the device flow so the user never handles the raw key:

1. `POST https://sleek.design/api/v1/device/start` (no auth) with body `{"source": "your-tool-slug"}`. The response contains a `verificationUrl`, a human-checkable `userCode`, a secret `deviceCode`, and a poll `interval` in seconds.
2. Show the user the `verificationUrl` and the `userCode`, and tell them to confirm the code matches before approving.
3. Poll `POST https://sleek.design/api/v1/device/poll` with `{"deviceCode": "..."}` every `interval` seconds. On `pending`, keep waiting. On `approved`, store `data.key` privately as `SLEEK_API_KEY` on that first read: the key is handed over once. On `expired` or `404 NOT_FOUND`, start a new flow. See [Device: Poll](endpoints.md#device-poll) for the response contract.

Fallback: send the user to **https://sleek.design/agents/setup**, which handles sign-in, plan upgrade, and key creation in one place, and ask them to paste the key back to you. Keys can also be managed at **https://sleek.design/dashboard/api-keys**. The full key value is shown only once at creation, and a free account holds one active key at a time.

**Plans**: free accounts can try the API with their one-time trial credits (about one design run), so a new user can see their first design before any payment decision. Sustained use requires the Pro plan or higher. This file carries no figures on purpose — read the current price, billing periods and credit allowance from **https://sleek.design/agents.md**, which is generated from Sleek's live pricing, and quote them from there. When cost becomes relevant (the user asks, an upgrade is needed to continue, or you're about to send them to a payment page), state that pricing plainly, including the yearly option, so the user sees a payment step coming before they reach it.

---

## Quick Reference: All Endpoints

Every endpoint the API exposes:

| Method   | Path                                           | Scope             |
| -------- | ---------------------------------------------- | ----------------- |
| `GET`    | `/api/v1/projects`                             | `projects:read`   |
| `POST`   | `/api/v1/projects`                             | `projects:write`  |
| `GET`    | `/api/v1/projects/:id`                         | `projects:read`   |
| `DELETE` | `/api/v1/projects/:id`                         | `projects:write`  |
| `GET`    | `/api/v1/projects/:id/components`              | `components:read` |
| `GET`    | `/api/v1/projects/:id/components/:componentId` | `components:read` |
| `GET`    | `/api/v1/references`                           | any valid key     |
| `POST`   | `/api/v1/projects/:id/chat/messages`           | `chats:write`     |
| `GET`    | `/api/v1/projects/:id/chat/runs/:runId`        | `chats:read`      |
| `POST`   | `/api/v1/projects/:id/chat/runs/:runId/cancel` | `chats:write`     |
| `POST`   | `/api/v1/screenshots`                          | `screenshots`     |
| `POST`   | `/api/v1/share-cards`                          | `screenshots`     |
| `POST`   | `/api/v1/device/start`                         | public, no auth   |
| `POST`   | `/api/v1/device/poll`                          | public, no auth   |

Create a key holding only the scopes the task uses.

Every row above is specified in full — request body, response shape, field defaults, status codes — in [endpoints.md](endpoints.md). This table is enough to pick an endpoint; read the reference when you need a contract detail it doesn't carry.

---

## Error Shapes

```json
{
  "defined": true,
  "code": "FORBIDDEN",
  "status": 403,
  "message": "...",
  "data": { "url": "https://sleek.design/..." }
}
```

| 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                                   |
| 429  | `TOO_MANY_REQUESTS`     | Render cap: 1000 screenshots + share cards per hour per org, counted on API-key requests only |
| 500  | `INTERNAL_SERVER_ERROR` | Server error                                                             |

`401`, `403` and `429` bodies may include `data.url`: a page where the user can fix the condition (create a key, upgrade the plan). Share it as-is.

Chat run-level errors (inside `data.error`):

| Code                              | Meaning                                                    |
| --------------------------------- | ---------------------------------------------------------- |
| `out_of_credits`                  | Organization has no credits left                           |
| `execution_failed`                | AI execution error                                         |
| `cancelled`                       | Run cancelled via the cancel endpoint                      |
| `request_message_persist_failed`  | The run failed before reaching the AI; the message was never stored |

For `out_of_credits`, relay `error.url` and wait for the user to resolve it. Follow [Safe retries](designing.md#2-send-a-chat-message) for replay versus a new attempt after either recoverable failure.