---
title: "Send a message"
method: POST
path: "/v1/{account_id}/chats/{chat_id}/messages"
tags: ["Messaging"]
---

# Send a message

`POST /v1/{account_id}/chats/{chat_id}/messages`

## Request

- Base URL: `https://api.curviate.com`
- URL: `https://api.curviate.com/v1/{account_id}/chats/{chat_id}/messages`
- Auth: HTTP bearer

Sends a message into a chat: text, attachments, or both. This call keeps nothing and logs nothing. Once sent it is a message in the account's inbox, so reading that conversation back through Curviate stores its body in your tenant's inbox records, with no expiry. COMPANY_ chat ids send as the page.

## Path parameters

- `account_id` string, required
- `chat_id` string, required

## Request body

- object
  - `text` string: Message text (1-8000 chars). Optional when at least one attachment is supplied.
  - `quote_id` string: Optional message ID to quote or reply to.
  - `attachments` object[]: Optional file attachments, base64-encoded: at most 5 MiB per file and 9 MiB for the whole request body (base64 adds about a third).
    - `content` string, required: Base64-encoded file bytes.
    - `content_type` string, required: Attachment MIME type (e.g. image/png, application/pdf).
    - `filename` string, required: File name for the attachment.

## Response `201`

Message sent. Returns the new message_id and sent_as, the acting identity. Reply as a company page simply by sending into one of its chat ids (from GET /v1/{account_id}/inboxes/{inbox_id}/chats): a COMPANY_ chat id (e.g. `COMPANY_83734124_2-...`) sends AS THE PAGE and echoes sent_as:{kind:'company',company_id,name} (company_id is null when the page could not be correlated to a managed page). Any other chat id sends as the connected member and echoes sent_as:{kind:'personal'}. Never infer the acting identity from the message's sender field, only from sent_as.

- object
  - `object` 'message_sent', required: Response type discriminator.
  - `message_id` union, required: The sent message's identifier. Null when no message was actually sent, and an array when the message was delivered as several messages, one per attachment.
    - string
    - string[]
  - `sent_as` object, required: The identity this message was actually sent as.
    - `kind` 'personal' | 'company': Which identity sent the message.
    - `company_id` string, nullable: Company inboxes only. Null when this page is not one of the account's managed companies on Curviate, even though the page itself, and its name, are still known.
    - `name` string, nullable: Company inboxes only. The page's display name, or null in the rare case the page itself could not be resolved at all.
  - `safety_warning` SafetyWarning: Present on a successful response when this account crossed an account-safety ceiling while the affected budget row is on the default warn posture. The action still happened. Field-identical to the BUDGET_EXHAUSTED error body except that blocked is false and hint.message describes the outcome, so one branch handles both postures and switching the account to enforce is a configuration change rather than a client rewrite.
    - `row` string, nullable, required: The budget row that breached, for example profile_views or pending_invites. Null when the breach is not about a row: an activity_window warning on an action that spends no budget of its own (editing a message, dismissing a notification, a Recruiter or Sales Navigator admin action) is still governed by the hours the account works in. Read hint.parameter for what to change; whenever this is null it names posture, because the activity window edges are set per action type and this action has none, so the levers that reach it are the account timezone and posture.
    - `reset_at` string, nullable, required: The instant the refusal lifts: the window roll on a ceiling refusal, the next window open on an activity-window one. Null in the two cases no clock frees, the pending_invites gauge and InMail credits (row inmail).
    - `hint` object, required
      - `parameter` string, required: The settable parameter on PATCH /v1/{account_id}/safety-policy.
      - `message` string, required: What the condition is and what changing that parameter would do. This is the one field whose text differs from the BUDGET_EXHAUSTED refusal: here it says the action went through, and on a ceiling breach how far past the ceiling this row now stands, rather than telling you to set posture to warn when it already is. Branch on parameter, reason and blocked, never on this text.
    - `reason` 'ceiling' | 'activity_window', required: Which rule was crossed. ceiling means the row's configured limit is spent; activity_window means the account is outside the hours it works in, which is a different fact with a different remedy. hint.parameter names the right setting for each.
    - `blocked` boolean, required: Always false here. True on the BUDGET_EXHAUSTED refusal carrying the same payload.

## Other responses

- `400`: Invalid request: at least one of text or attachments must be supplied.
- `401`: Missing or invalid API key.
- `404`: The chat does not exist for this account. An id whose connection was replaced or removed also stops resolving here, and it is already absent from the list, so re-read `GET /v1/accounts` for the current id.
- `413`: Payload too large. Three triggers, smallest first: the platform's own ceiling on total request size, which rejects bodies from roughly 1 MB and is the one most callers hit; then the caps enforced here, 5 MiB per attachment and 9 MiB for the whole request body. Base64 inflates a file by about 33 percent, so a 5 MiB file costs about 6.7 MiB of the body budget. Send fewer or smaller attachments; retrying the same request unchanged will not help.
- `415`: Unsupported media type: the request must use application/json.
- `422`: The account is restricted.
- `429`: Rate limited.
- `500`: Internal error.
- `502`: A temporary error occurred. Please try again.
- `503`: Service unavailable.
- `504`: Gateway timeout.

---

[API](https://skmtc.dev/curviate/apis/curviate-api.md) · [All operations](https://skmtc.dev/curviate/apis/curviate-api/llms.txt) · [OpenAPI document](https://skmtc.dev/curviate/apis/curviate-api/revisions/eab848801d95?raw)
