---
title: "QUEUE: append a message to a durable, wallet-scoped queue."
method: POST
path: "/api/queue/enqueue"
tags: ["queue"]
---

# QUEUE: append a message to a durable, wallet-scoped queue.

`POST /api/queue/enqueue`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/queue/enqueue`
- Auth: API key in header `PAYMENT-SIGNATURE`

QUEUE: append a message to a durable, wallet-scoped queue. Workers pull it later with queue.lease and confirm with queue.ack. Use it to buffer tasks, hand work between agent runs, or fan work to a consumer. Body is arbitrary JSON (≤256 KB). Optional maxAttempts before a message dead-letters. Kept on a rolling 90-day window. No account or API key — pay per call with x402.

## Request body

- object
  - `queue` string, required: Queue name, 1-64 chars of [A-Za-z0-9._:-]. e.g. "jobs".
  - `body` unknown
  - `maxAttempts` integer: Deliveries before the message moves to the dead-letter status. Default 10.

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request — not charged. error.code: BAD_REQUEST or INVALID_PARAM (parameter validation; error.details.issues lists each problem), MALFORMED_JSON, or a request-specific code. Other client errors: 405 METHOD_NOT_ALLOWED (wrong verb; see the Allow header), 413 PAYLOAD_TOO_LARGE.
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. Not charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)