Qstash

QStash is Upstash's serverless task scheduling and queue service — designed specifically for the edge/serverless deployment model. Core primitives: (1) publish an HTTP message to a URL with a delay (schedule a future webhook), (2) create a schedule (recurring cron-based HTTP callback), (3) queue messages for ordered delivery with retry logic, (4) topic fanout to multiple endpoints. For agents: schedule a task for future execution (POST to QStash with delay, QStash calls your agent endpoint later), set up recurring work (create a cron schedule pointing to an agent endpoint), and implement reliable async processing with retry guarantees. Best-in-class DX for serverless contexts. Confidence is docs-derived.

Bearer token auth: Authorization: Bearer {token}. QStash tokens from Upstash Console → QStash → Tokens. Receiving endpoint must verify incoming requests: QStash signs messages with a signing key (HMAC-SHA256); verify Upstash-Signature header using the QStash current signing key. SDK (qstash-js, qstash-py) handles signature verification automatically. Token rotation supported (two signing keys to enable zero-downtime rotation). HTTPS enforced. Upstash account required.

upstash.com/docs/qstash provides comprehensive documentation: publishing guide, schedule creation, queue documentation, signature verification, and SDK guides for JavaScript and Python. Getting started is fast: create free Upstash account, generate QStash token, first scheduled message in under 5 minutes. qstash-js SDK for Node.js/Edge. REST-only is also trivial. Strongly recommended over raw background jobs for serverless architectures. Community via Upstash Discord. Free tier: 500 messages/day.

REST API at qstash.upstash.io/v2. Resources: publish, schedules, queues, messages, topics. POST /v2/publish/{destination-url} enqueues a message to be delivered to the destination. Query params: Upstash-Delay: {delay-in-seconds}, Upstash-Not-Before: {unix-timestamp}, Upstash-Retries: {count}. POST /v2/schedules creates a recurring cron schedule ({destination, cron, body}). GET /v2/schedules lists active schedules. DELETE /v2/schedules/{id} removes a schedule. GET /v2/messages/{id} checks message delivery status. POST /v2/queues/{queue}/enqueue for ordered queue delivery. Body is forwarded verbatim to the destination URL.

Message delivery status via GET /v2/messages/{id}: queued, delivered, failed, cancelled. Failed deliveries retry with exponential backoff (configurable retries: 0–5). After max retries: message moved to Dead Letter Queue (retrievable via API). HTTP errors from destination: 4xx marks as failed (no retry by default for client errors); 5xx retries. Upstash QStash SLA: 99.9%. Schedule execution is at-least-once; idempotency keys via Upstash-Content-Based-Deduplication header. Latency for delayed messages: typically within seconds of scheduled time.