> ## Documentation Index > Fetch the complete documentation index at: https://developers.workchats.com/llms.txt > Use this file to discover all available pages before exploring further. # Get a file > Returns a file attached to a message the bot can read in the conversation, with a download link. The link is signed, needs no token and can be opened for 15 minutes; ask again for a fresh one. It redirects to a storage download that works for up to an hour. Access is checked when the link is issued, so a link issued before the App lost access keeps working until it expires. Needs `files:read`. Limited to 100 requests a minute per installation. ## OpenAPI ````yaml /openapi/prod.json get /v1/conversations/{conversation_id}/files/{id} openapi: 3.0.0 info: contact: email: support@workchats.com name: Workchats API Support description: > Post messages into Workchats as an installed App's bot user, and read the people and conversations it can reach. Authenticate with the bot token from the OAuth install, in the Authorization header as `Bearer wc_bot_…`. Every error response has the shape `{"ok": false, "error": {"code", "message"}, "request_id"}`. Lists are cursor-paginated: pass `limit` (default 200, at most 1000) and the previous page's `next_cursor` as `cursor`. `next_cursor` is null on the last page. ## Callbacks Workchats POSTs events to the App's registered callback URL, over HTTPS only. Answer with any 2xx within 3 seconds. Anything else, including a redirect, which is never followed, is retried after 1, 5 and 30 minutes with the same event `id`, so ignore an `id` you have already handled. `X-Workchats-Attempt` counts the attempts from 1. Every event has the shape `{"id", "type", "workspace_id", "created_at", "data"}`: - `app.uninstalled`: `data` is `{"removed_by": {"id": "usr_…"} | null, "reason": "admin" | "app_disabled"}`. A company admin uninstalled the App, or Workchats disabled it (`removed_by` is null). The token has already stopped working. Revoking the token yourself through `POST /oauth/revoke` sends nothing. - `directory.changed`: `data` is `{"kind", "id"}`. Re-read the user with `GET /v1/users/{id}` or the conversation with `GET /v1/conversations/{id}`. Kinds: `user.created`, `user.updated` (name, email or title), `user.deactivated` (deactivated or removed), `conversation.created` (the bot was added), `conversation.renamed`, `conversation.archived` (groups), `conversation.deleted`, `app.removed_from_conversation`. User kinds need `users:read`; conversation kinds name only conversations the bot is, or was just, in. Ignore kinds you don't know. **Verifying a callback.** `X-Workchats-Signature` is `v1=` and the lower-case hex HMAC-SHA256 of `.`, keyed with the App's signing secret. Compare in constant time, and refuse a timestamp more than 5 minutes old. For 24 hours after the secret is rotated the header carries two signatures, `v1=,v1=`: accept the request if any one matches. Worked example: - Signing secret: `whsec_docs_example` - X-Workchats-Timestamp: 1790593600 - Body: `{"id":"evt_5f0c7a52-6d1e-4c1b-9a8e-2f4b7c3d1e90","type":"directory.changed","workspace_id":"cmp_0b7e4c1a-2d3f-4a5b-8c6d-7e8f9a0b1c2d","created_at":"2026-09-28T11:06:40Z","data":{"kind":"user.deactivated","id":"usr_9a1b2c3d-4e5f-4a6b-8c7d-9e0f1a2b3c4d"}}` - X-Workchats-Signature: v1=42ec825e4ad44370ea02385d30a001c349640cff974ed895361b3c7a080e5339 title: Workchats Public API version: '1.0' servers: - url: https://public-api.workchats.com variables: {} security: - bearerAuth: [] tags: - description: Token checks name: Auth - description: Groups and channels the bot is a member of, and their messages name: Conversations - description: Files attached to messages the bot can read name: Files - description: Send, edit and delete the bot's messages name: Messages - description: Code exchange and token revocation name: OAuth - description: The workspace's people name: Users paths: /v1/conversations/{conversation_id}/files/{id}: get: tags: - Files summary: Get a file description: >- Returns a file attached to a message the bot can read in the conversation, with a download link. The link is signed, needs no token and can be opened for 15 minutes; ask again for a fresh one. It redirects to a storage download that works for up to an hour. Access is checked when the link is issued, so a link issued before the App lost access keeps working until it expires. Needs `files:read`. Limited to 100 requests a minute per installation. operationId: WorkchatsApiServerWeb.PublicApi.FileController.show parameters: - description: >- The group (`grp_`) or named channel (`chn_`) of a message carrying the file in: path name: conversation_id required: true schema: type: string - description: File id, `fil_` prefixed, from a message's `files` in: path name: id required: true schema: type: string responses: '200': content: application/json: schema: $ref: '#/components/schemas/PublicApiFileResponse' description: The file '400': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: '`token_in_query`' '401': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: '`not_authed`, `invalid_auth` or `token_revoked`' '403': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: >- `missing_scope` (the token lacks `files:read`) or `not_in_conversation` (the App was removed from the conversation) '404': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: >- `conversation_not_found` (no such group or channel, or the App was never a member of it) or `file_not_found` (no message the App can read in the conversation carries the file, or the file was deleted) '406': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: '`not_acceptable`: the Accept header does not allow application/json' '429': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: '`rate_limited`: retry after the Retry-After header''s seconds' '500': content: application/json: schema: $ref: '#/components/schemas/PublicApiError' description: '`internal_error`: something went wrong on our side' callbacks: {} security: - bearerAuth: [] components: schemas: PublicApiFileResponse: properties: file: properties: id: description: '`fil_` prefixed' type: string mimetype: type: string name: description: The file name it was uploaded with type: string size: description: Bytes type: integer url: description: >- A signed link that needs no token and can be opened for 15 minutes. It redirects to a storage download that works for up to an hour after it is opened. A link issued before the App lost access to the message keeps working until it expires. Treat it and the download as secrets while they last. format: uri type: string required: - id - name - mimetype - size - url type: object ok: enum: - true type: boolean required: - ok - file title: PublicApiFileResponse type: object PublicApiError: description: Every non-2xx response from the public API. example: error: code: token_revoked message: The token has been revoked. ok: false request_id: F7p0mJcXk3tq2x0AAAAB properties: error: properties: code: description: >- Stable, machine-readable error code. Each code always comes with the same HTTP status, except `client_error` and `server_error`, which carry the response's own 4xx or 5xx status. New codes may be added; treat an unknown one as a generic failure. type: string x-extensible-enum: - cannot_dm_user - client_error - conversation_archived - conversation_not_found - file_not_found - idempotency_key_reused - internal_error - invalid_auth - invalid_blocks - invalid_client - invalid_cursor - invalid_grant - invalid_request - message_not_found - missing_idempotency_key - missing_scope - not_acceptable - not_allowed_in_conversation - not_authed - not_found - not_in_conversation - payload_too_large - rate_limited - server_error - token_in_query - token_revoked - unsupported_grant_type - unsupported_media_type - user_deactivated - user_not_found message: description: Human-readable explanation type: string required: - code - message type: object ok: enum: - false type: boolean request_id: description: Also sent as the X-Request-Id header. Quote it to support. type: string required: - ok - error - request_id title: PublicApiError type: object securitySchemes: bearerAuth: description: Bot token (`wc_bot_live_…` or `wc_bot_test_…`) from the OAuth install scheme: bearer type: http ````