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

Instagram only: sends one private reply to a comment. It arrives as a direct message to the commenter.

https://api.postfa.st/Auth: pf-api-keyRate limit: 300 requests per day, 100 per minute

Instagram only, and only where the comment allows it

Check canPrivateReply on the inbound comment item before offering this action. It is true only on eligible Instagram comments and null on every other platform.

The reply arrives as a direct message to the person who left the comment, and may land in their Message Requests folder rather than their main inbox.

One private reply per comment, within 7 days

Instagram allows exactly one private reply per comment. A second attempt returns inbox.privateReplyAlreadySent.

The window closes 7 days after the comment was left. After that the request returns inbox.privateReplyWindowExpired.

A comment that was never eligible returns inbox.privateReplyNotSupported.

Path parameters

idstring (UUID)required

The Instagram comment item id, from /social-inbox/conversations/{id}/items. The item must have canPrivateReply: true.

Request body

textstringrequired

The private reply body, maximum 1,000 bytes. Emoji and non-Latin characters cost several bytes each, so the character count you can send is lower than 1,000. The conversation's maxPrivateReplyLengthBytes carries the same limit.

idempotencyKeystringoptional

Optional client-supplied key. A retry that carries the same key will not send a second time, so it is safe to retry after a network timeout.

Response

201 Created The created OUTBOUND item recording the private reply.

idstring (UUID)required

Item id. This is the value the reply, private-reply, and state routes take as their path parameter.

conversationIdstring (UUID)required

Conversation the item belongs to.

kindstringrequired

Item type. Always COMMENT today.

directionstringrequired

INBOUND for a comment you received, OUTBOUND for a reply you sent.

INBOUNDOUTBOUND
externalItemIdstring | nulloptional

The platform's comment id. null on an outbound reply that is still sending.

parentExternalItemIdstring | nulloptional

Platform id of the parent comment, for threading.

authorUsernamestring | nulloptional

Author's username, when the platform exposes it.

textstring | nulloptional

Comment or reply body.

statestringrequired

Moderation state on the platform, changed via the state route.

VISIBLEHIDDENDELETED
deliveryStatusstring | nulloptional

Outbound items only: how far the send got. null on inbound comments.

PENDINGSENTFAILED
authoredByUserIdstring (UUID) | nulloptional

Workspace member who sent an outbound item. null for replies sent with an API key, because keys are workspace-scoped rather than user-scoped.

platformCreatedAtISO 8601required

When the platform recorded the comment.

createdAtISO 8601required

When PostFast stored the item.

canPrivateReplyboolean | nulloptional

Instagram inbound comments: whether this comment is still eligible for /social-inbox/items/{id}/private-reply. null elsewhere.