---
title: "Reply on a support case"
method: POST
path: "/v1/support/cases/{caseId}/messages"
tags: ["Support"]
---

# Reply on a support case

`POST /v1/support/cases/{caseId}/messages`

## Request

- Base URL: `https://api.banksync.io`
- URL: `https://api.banksync.io/v1/support/cases/{caseId}/messages`
- Auth: one of:
  - API key in header `X-API-Key`
  - HTTP bearer

Reply on a case, as the key’s user. BankSync support is notified straight away; a reply cannot be taken back. A reply on a case closed too long ago is refused: raise a new one.

## Path parameters

- `caseId` string, required: Support case ID, from the list

## Headers

- `Idempotency-Key` string: Makes a retry safe: the same key with the same request replays the first answer for 24 hours instead of running twice, and the same key with a different request is a 409 `IDEMPOTENCY_KEY_REUSED`. Refusals a retry can outlive — 408, 409, 423, 425, 429 and every 5xx — are never replayed, so retrying with the same key after the cause clears runs the request.

## Request body

- object
  - `message` string, required: The reply to BankSync support
  - `idempotencyKey` string: A retry with the same key opens or posts nothing new

## Response `201`

The message

- object
  - `success` true, required
  - `data` object, required
    - `messageId` string, required

## Other responses

- `400`: Invalid input: a subject or message missing or too long
- `401`: Unauthorized
- `403`: Forbidden — a missing scope, a credential narrowed to some accounts, an installed app, or a case the key’s user did not raise (closing)
- `404`: Not found — a case the key’s user may not see answers exactly as one that does not exist; or support is not enabled for this workspace
- `409`: Conflict — the case moved since you read it (already closed), or it was closed too long ago to reply on: raise a new one
- `429`: Too many requests — the key’s rate limit, or the user already has ten open cases (`TOO_MANY_OPEN_CASES`): reply on one of those
- `503`: Support is temporarily unavailable; retry shortly

---

[API](https://skmtc.dev/banksync/apis/banksync-api.md) · [All operations](https://skmtc.dev/banksync/apis/banksync-api/llms.txt) · [OpenAPI document](https://skmtc.dev/banksync/apis/banksync-api/revisions/94465f5ee922?raw)