POST/social-inbox/items/{id}/reply

One reply in flight at a time

Sending a second reply to the same comment while the first is still being delivered returns inbox.replyInProgress. Wait for the first response instead of retrying immediately.

If you do need to retry after a network timeout, pass the same idempotencyKey so the reply cannot be posted twice.

Repeated identical replies are rejected

Sending the same reply text over and over across a workspace returns inbox.repetitiveReply. The check ignores case and spacing, counts only replies that were actually sent, and resets on a rolling 24-hour window.

Short courtesy replies such as Thanks! are exempt, so this only bites on the pattern platforms treat as spam: mass identical comments. If you are generating replies programmatically, vary the wording rather than retrying the same text.

A restricted account pauses replies for 24 hours

When Facebook or Instagram refuses a reply because it has restricted the account (a spam or abuse block), PostFast pauses replies from that account for 24 hours. The refused reply fails with inbox.replyPaused, and so does every further reply from that account until the pause ends, without reaching the platform. PostFast holds them because calls that reach a platform during its block can extend it.

description carries the platform's own reason and the time the pause ends, as an ISO 8601 UTC timestamp. If you send replies in bulk, stop sending from that account until then: every call fails the same way and still counts against your rate limit. Other accounts are unaffected, and hiding, deleting, and private replies keep working.

After the pause, the next reply shows whether the block has lifted; if the account is still restricted, a new 24-hour pause starts. Retrying a reply that already went out, with the same idempotencyKey, still returns the stored reply during a pause.

{
  "statusCode": 400,
  "message": "inbox.replyPaused",
  "error": "BAD_REQUEST",
  "description": "Facebook restricted this account, so replies from it are paused until 2026-08-07T09:16:05.000Z. Facebook said: You're temporarily restricted from commenting until 8 August."
}