openapi: 3.0.3
info:
  title: QStash Dead Letter Queue Flow Control 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: Flow Control
  description: Manage flow control keys for rate and parallelism limiting
paths:
  /flowControl/{key}:
    get:
      operationId: getFlowControlKey
      summary: Get flow control key details
      description: Retrieve metrics and configuration for a flow control key, including waitlist size, current parallelism and rate counts, and pause/pin status.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Flow control key details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FlowControlInfo'
        '404':
          $ref: '#/components/responses/NotFound'
  /flowControl/{key}/pause:
    post:
      operationId: pauseFlowControlKey
      summary: Pause delivery for a flow control key
      description: Pause all message delivery for the specified flow control key.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Flow control key paused
  /flowControl/{key}/resume:
    post:
      operationId: resumeFlowControlKey
      summary: Resume delivery for a flow control key
      description: Resume message delivery for a paused flow control key.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Flow control key resumed
  /flowControl/{key}/pin:
    post:
      operationId: pinFlowControlKey
      summary: Pin flow control key configuration
      description: Lock the parallelism and/or rate configuration of a flow control key to prevent override by incoming message headers.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      - name: parallelism
        in: query
        description: Maximum parallel deliveries to pin
        schema:
          type: integer
      - name: rate
        in: query
        description: Rate limit to pin
        schema:
          type: integer
      - name: period
        in: query
        description: Rate period in seconds
        schema:
          type: integer
      responses:
        '200':
          description: Flow control key pinned
  /flowControl/{key}/unpin:
    post:
      operationId: unpinFlowControlKey
      summary: Unpin flow control key configuration
      description: Allow incoming messages to override the flow control key configuration.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      - name: parallelism
        in: query
        description: Unpin parallelism setting
        schema:
          type: boolean
      - name: rate
        in: query
        description: Unpin rate setting
        schema:
          type: boolean
      responses:
        '200':
          description: Flow control key unpinned
  /flowControl/{key}/resetRate:
    post:
      operationId: resetFlowControlRate
      summary: Reset rate count for a flow control key
      description: Reset the rate count and end the current rate period immediately.
      tags:
      - Flow Control
      parameters:
      - name: key
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Rate reset
  /flowControl:
    get:
      operationId: listFlowControlKeys
      summary: List all flow control keys
      description: Retrieve all active flow control keys for this account.
      tags:
      - Flow Control
      responses:
        '200':
          description: List of flow control keys
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/FlowControlInfo'
  /globalParallelism:
    get:
      operationId: getGlobalParallelism
      summary: Get global parallelism status
      description: Retrieve the global parallelism maximum and current active delivery count across all queues and flow control keys.
      tags:
      - Flow Control
      responses:
        '200':
          description: Global parallelism info
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GlobalParallelism'
components:
  schemas:
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
          description: Human-readable error message
    GlobalParallelism:
      type: object
      properties:
        max:
          type: integer
          description: Maximum global parallel deliveries allowed by plan
        active:
          type: integer
          description: Current number of active parallel deliveries globally
    FlowControlInfo:
      type: object
      properties:
        key:
          type: string
          description: Flow control key name
        waitlistSize:
          type: integer
          description: Number of messages currently waiting due to flow control
        parallelism:
          type: integer
          description: Configured maximum parallelism
        activeParallelism:
          type: integer
          description: Current active parallel deliveries
        rate:
          type: integer
          description: Configured rate limit (messages per period)
        period:
          type: integer
          description: Rate period in seconds
        currentRate:
          type: integer
          description: Current rate count in active period
        paused:
          type: boolean
          description: Whether delivery is paused for this key
        pinned:
          type: boolean
          description: Whether the configuration is pinned
  responses:
    NotFound:
      description: Resource not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  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