> ## Documentation Index > Fetch the complete documentation index at: https://docs.closient.com/llms.txt > Use this file to discover all available pages before exploring further. # TRMNL device setup > Called by TRMNL firmware on first boot. The device presents its MAC in the ``ID`` header; the server responds with an ``api_key`` (used as ``Access-Token`` on every subsequent call), a 6-char ``friendly_id``, the URL of the device's first image, and a suggested filename for local caching. If the MAC has never been seen, an unclaimed :class:`BYOSDevice` row is created — the device starts in the ``unclaimed`` state and renders the BYOS fallback image until an operator links it to an organization. **Auth:** unauthenticated. The TRMNL firmware doesn't have an ``Access-Token`` yet at this call. * ``200`` — setup succeeded; device may begin polling ``/api/display``. * ``400`` — the ``ID`` header is missing or not a 12-char hex MAC. ## OpenAPI ````yaml /openapi/openapi-byos.json get /byos/api/setup/ openapi: 3.1.0 info: title: BYOS API version: 1.0.0 description: > Closient's TRMNL-compatible **Bring Your Own Server** endpoints. Powers e-ink analytics displays — devices poll ``/api/setup/`` on first boot, then ``/api/display`` on a schedule to fetch the image they should paint. The wire protocol matches TRMNL's BYOS contract verbatim so off-the-shelf reTerminal firmware works without modification. ## Authentication All endpoints require an API key passed via the `X-API-Key` HTTP header, unless otherwise noted. ``` X-API-Key: csb__ ``` Generate API keys in **Settings > API Keys** in your dashboard, or via the Account API. Session-based (cookie) authentication is also accepted for browser-based access. ## Rate Limits | Tier | Requests / minute | Requests / day | |-------------|-------------------|----------------| | Default | 300 | 10,000 | | Custom | Contact us | Contact us | Rate-limit headers are included on every response so callers can self-throttle without hitting our 429s ("informed governor"): - `RateLimit-Policy` — every active window, e.g. `300;w=60, 10000;w=86400` - `RateLimit-Limit` — quota for the **most-restrictive** currently-active window - `RateLimit-Remaining` — requests left in that window - `RateLimit-Reset` — seconds until that window resets (relative; clock-skew safe) Legacy `X-RateLimit-*` aliases are also emitted for back-compat. `X-RateLimit-Reset` keeps the absolute Unix-timestamp shape to avoid breaking existing consumers. When rate-limited, you receive `429 Too Many Requests` with a `retry_after_seconds` field in the error envelope and a `Retry-After` header. ## Pagination List endpoints return paginated results in this envelope: ```json { "data": [...], "pagination": { "page": 1, "page_size": 25, "total_count": 342, "total_pages": 14, "has_next": true, "has_previous": false } } ``` Use `?page=2&page_size=50` query parameters. Maximum page size is 100. ## Error Responses All errors conform to [RFC 9457 Problem Details](https://www.rfc-editor.org/rfc/rfc9457) with `Content-Type: application/problem+json`: ```json { "type": "https://closient.com/docs/errors/not_found", "title": "Not Found", "status": 404, "detail": "The requested resource was not found.", "error_code": "not_found", "retryable": false, "timestamp": "2026-03-31T12:00:00+00:00" } ``` Common error codes: `unauthorized` (401), `forbidden` (403), `not_found` (404), `validation_error` (422), `rate_limited` (429), `internal_error` (500). termsOfService: https://www.closient.com/terms/ servers: - url: https://www.closient.com security: [] externalDocs: description: Closient Documentation url: https://docs.closient.com paths: /byos/api/setup/: get: tags: - byos-trmnl summary: TRMNL device setup description: >- Called by TRMNL firmware on first boot. The device presents its MAC in the ``ID`` header; the server responds with an ``api_key`` (used as ``Access-Token`` on every subsequent call), a 6-char ``friendly_id``, the URL of the device's first image, and a suggested filename for local caching. If the MAC has never been seen, an unclaimed :class:`BYOSDevice` row is created — the device starts in the ``unclaimed`` state and renders the BYOS fallback image until an operator links it to an organization. **Auth:** unauthenticated. The TRMNL firmware doesn't have an ``Access-Token`` yet at this call. * ``200`` — setup succeeded; device may begin polling ``/api/display``. * ``400`` — the ``ID`` header is missing or not a 12-char hex MAC. operationId: apps_boards_api_trmnl_trmnl_setup parameters: [] responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/SetupOut' '400': description: Bad Request content: application/problem+json: schema: additionalProperties: true title: Response type: object '404': description: Not Found content: application/problem+json: schema: $ref: '#/components/schemas/ErrorOut' '405': description: Method Not Allowed content: application/problem+json: schema: $ref: '#/components/schemas/ErrorOut' '429': description: Too Many Requests content: application/problem+json: schema: $ref: '#/components/schemas/ErrorOut' components: schemas: SetupOut: description: |- Response to ``GET /api/setup/``. The TRMNL firmware persists ``api_key`` to flash and uses it on every subsequent call. ``image_url`` is the first image to paint — for an unclaimed device this is the fallback "register me" screen. examples: - api_key: d51229662e86a29fe6ab11a4ca1a4a41d141fc8b filename: closient-A1B2C3-3f9a2c1d8e.png friendly_id: A1B2C3 image_url: https://www.closient.com/byos/devices/A1B2C3/image.png message: '' status: 200 properties: api_key: description: >- Opaque per-device access token. Firmware stores this in flash and sends it in the ``Access-Token`` header on every subsequent call. title: Api Key type: string friendly_id: description: >- Short 6-character human-readable device label (e.g. ``A1B2C3``). Shown on the panel during first-boot and used in dashboard URLs. title: Friendly Id type: string image_url: description: >- Absolute URL the device should fetch to paint its first image. For an unclaimed device this points to the BYOS fallback image. title: Image Url type: string filename: description: >- Suggested filename for the device to use when caching the fetched image locally. title: Filename type: string message: default: '' description: >- Optional human-readable message — currently always empty on success. Future: post-firmware-update notes. title: Message type: string status: default: 200 description: >- TRMNL setup status code. Always 200 on success; 404 on devices that should refuse to operate (currently unused). title: Status type: integer required: - api_key - friendly_id - image_url - filename title: SetupOut type: object ErrorOut: title: ErrorOut type: object description: RFC 9457 Problem Details error body. properties: type: type: string format: uri title: type: string status: type: integer detail: type: string error_code: type: string retryable: type: boolean timestamp: type: string format: date-time required: - type - title - status - detail examples: - type: https://closient.com/docs/errors/not_found title: Not Found status: 404 detail: The requested resource was not found. error_code: not_found retryable: false timestamp: '2026-03-31T12:00:00+00:00' ````