openapi: 3.0.3
info:
  title: QStash Dead Letter Queue Messages API
  description: QStash is a serverless message queue and task scheduling REST API from Upstash that delivers HTTP messages to endpoints reliably without requiring any long-lived connections or infrastructure management. Built entirely on stateless HTTP requests, it is designed for serverless and edge runtimes where traditional message brokers are impractical. QStash supports automatic retries, CRON-based scheduling up to one year in advance, URL group broadcasting for fan-out delivery, FIFO queuing, dead-letter queues, and message deduplication.
  version: '2.0'
  contact:
    name: Upstash Support
    url: https://upstash.com/docs/qstash/overall/getstarted
  license:
    name: Upstash Terms of Service
    url: https://upstash.com/trust/terms.pdf
servers:
- url: https://qstash.upstash.io/v2
  description: QStash production API
security:
- BearerAuth: []
tags:
- name: Messages
  description: Publish and manage messages
paths:
  /publish/{destination}:
    post:
      operationId: publishMessage
      summary: Publish a message
      description: Publish a message to a destination URL or URL Group. QStash will store the message durably and deliver it to the destination with automatic retries on failure.
      tags:
      - Messages
      parameters:
      - name: destination
        in: path
        required: true
        description: Destination URL or URL Group name
        schema:
          type: string
        example: https://example.com/webhook
      - name: Upstash-Delay
        in: header
        description: Delay message delivery by this duration (e.g. "5m", "1h")
        schema:
          type: string
        example: 5m
      - name: Upstash-Retries
        in: header
        description: Number of retry attempts on delivery failure (0-5)
        schema:
          type: integer
          minimum: 0
          maximum: 5
      - name: Upstash-Retry-Delay
        in: header
        description: Delay expression between retries (supports math functions like pow, sqrt)
        schema:
          type: string
      - name: Upstash-Callback
        in: header
        description: URL to receive callback after successful delivery
        schema:
          type: string
          format: uri
      - name: Upstash-Failure-Callback
        in: header
        description: URL to receive callback on delivery failure after all retries
        schema:
          type: string
          format: uri
      - name: Upstash-Deduplication-Id
        in: header
        description: Manual deduplication ID; duplicate messages within 10 minutes are ignored
        schema:
          type: string
      - name: Upstash-Content-Based-Deduplication
        in: header
        description: Automatically deduplicate based on destination, body, and content headers
        schema:
          type: boolean
      - name: Upstash-Timeout
        in: header
        description: Timeout for the delivery request (e.g. "30s")
        schema:
          type: string
      - name: Upstash-Not-Before
        in: header
        description: Unix timestamp before which delivery should not occur
        schema:
          type: integer
      - name: Upstash-Schedule-Id
        in: header
        description: Unique schedule ID; used to create or overwrite a schedule
        schema:
          type: string
      - name: Upstash-Cron
        in: header
        description: CRON expression to schedule recurring delivery (e.g. "0 0 * * *")
        schema:
          type: string
      - name: Upstash-Method
        in: header
        description: HTTP method to use when calling the destination (default POST)
        schema:
          type: string
          enum:
          - GET
          - POST
          - PUT
          - PATCH
          - DELETE
          - HEAD
      requestBody:
        description: Message payload to deliver to the destination
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
            example:
              hello: world
          application/octet-stream:
            schema:
              type: string
              format: binary
          text/plain:
            schema:
              type: string
      responses:
        '201':
          description: Message published successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PublishResponse'
        '202':
          description: Duplicate message detected; existing message returned
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PublishResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'
  /batch:
    post:
      operationId: batchPublish
      summary: Publish multiple messages in a single request
      description: Publish multiple messages in a single batch request. Messages can target different destinations, URL Groups, or queues. If one message fails, the others still proceed.
      tags:
      - Messages
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: array
              items:
                $ref: '#/components/schemas/BatchMessage'
            example:
            - destination: https://example.com/endpoint1
              body: '{"event":"ping"}'
              headers:
                Content-Type: application/json
            - destination: https://example.com/endpoint2
              body: '{"event":"pong"}'
      responses:
        '200':
          description: Batch result; includes per-message success or error
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/BatchResponseItem'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /enqueue/{queueName}/{destination}:
    post:
      operationId: enqueueMessage
      summary: Enqueue a message to a FIFO queue
      description: Add a message to the specified FIFO queue for ordered delivery to the destination URL.
      tags:
      - Messages
      parameters:
      - name: queueName
        in: path
        required: true
        description: Name of the target queue
        schema:
          type: string
      - name: destination
        in: path
        required: true
        description: Destination URL for message delivery
        schema:
          type: string
      - name: Upstash-Delay
        in: header
        description: Delay message delivery by this duration
        schema:
          type: string
      - name: Upstash-Retries
        in: header
        description: Number of retry attempts
        schema:
          type: integer
      - name: Upstash-Deduplication-Id
        in: header
        description: Manual deduplication ID
        schema:
          type: string
      requestBody:
        description: Message payload
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '201':
          description: Message enqueued successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PublishResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'
components:
  responses:
    RateLimited:
      description: Rate limit exceeded
      headers:
        Burst-RateLimit-Limit:
          description: Maximum requests allowed in the current 1-second window
          schema:
            type: integer
        Burst-RateLimit-Remaining:
          description: Requests remaining in the current window
          schema:
            type: integer
        Burst-RateLimit-Reset:
          description: Unix timestamp when the rate limit window resets
          schema:
            type: integer
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    Unauthorized:
      description: Missing or invalid authentication token
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    BadRequest:
      description: Invalid request parameters
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  schemas:
    BatchMessage:
      type: object
      required:
      - destination
      properties:
        destination:
          type: string
          description: URL, URL Group name, or queue destination
        url:
          type: string
          description: Alternative to destination for direct URL targeting
        urlGroup:
          type: string
          description: URL Group identifier for fan-out delivery
        queue:
          type: string
          description: Queue name for FIFO delivery
        headers:
          type: object
          additionalProperties:
            type: string
          description: Request headers to include (supports Upstash-* headers)
        body:
          type: string
          description: Message payload as string (JSON, XML, etc.)
        delay:
          type: string
          description: Delay before delivery (e.g. "5s", "1m")
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
          description: Human-readable error message
    PublishResponse:
      type: object
      properties:
        messageId:
          type: string
          description: Unique identifier for the published message
          example: msg_2XavMmRcJHJf7HkNtNqjfVf8uQe
        url:
          type: string
          description: Destination URL the message will be delivered to
          example: https://example.com/webhook
    BatchResponseItem:
      type: object
      properties:
        messageId:
          type: string
          description: Message ID for successfully queued messages
        url:
          type: string
          description: Destination URL
        error:
          type: string
          description: Error message if this particular batch item failed
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: Bearer token obtained from the Upstash console at https://console.upstash.com/qstash. Alternatively, pass as query parameter `qstash_token`.
externalDocs:
  description: QStash Documentation
  url: https://upstash.com/docs/qstash/overall/getstarted