Acknowledge a processed message

Last updated Oct 2, 2026

POST /spools/{spool}/ack

Completes the delivery: the message is durably removed from its queue. The lease names the queue, so the op is spool-scoped — a wrong queue is unrepresentable.

Sample

curl -X POST "$SPOOLER_API/spools/<spool>/ack" \
  -H "Authorization: Bearer $SPOOLER_KEY" \
  -H "Spooler-Lease: <lease>"

Parameters

Name	In	Type	Required	Description
spool	path	IdentName, 1–63 chars, ^[A-Za-z0-9_:-]+$	yes	The spool name.
Spooler-Lease	header	Lease, 16–256 chars, ^[A-Za-z0-9_-]+$	yes	The lease from a receive, presented back.

Responses

Status	Description
204	Acknowledged.
400	The request is malformed; the kind names the problem.
401	The API key is missing or not recognized.
402	The account is suspended.
403	A plan limit refuses the operation; the kind names it. A 403 without a kind, on any operation, means the API key is blocked.
404	The spool or queue does not exist; the kind says which.
409	Concurrent state refuses the operation; the kind names it.
410	The lease no longer settles anything: expired, already settled, or predates a primary change.
429	The per-account request rate cap is exceeded. The body names the kind (rate_limited); the wait is the Retry-After header and is not repeated in the body. Headers are as structured as the body, and this one is the header HTTP defines for a wait.
500	The server failed; kind operation_unconfirmed means the write was accepted but its durability is unknown.
503	The spool is momentarily unavailable.

429 headers

Header	Description
Retry-After	Seconds until the next request is admitted, whole and at least 1; always the delay-seconds form, never an HTTP-date.