spec: API Commons Rate Limits 0.1
provider: Speechmatics
providerId: speechmatics
created: 2026-06-12
modified: 2026-06-12
url: https://docs.speechmatics.com/speech-to-text/realtime/limits
rateLimits:
  - name: Real-Time Concurrent Sessions (Free)
    scope: account
    plan: Free
    type: concurrency
    limit: 2
    unit: concurrent_sessions
    notes: Maximum simultaneous WebSocket connections for Free tier accounts.

  - name: Real-Time Concurrent Sessions (Pro)
    scope: account
    plan: Pro
    type: concurrency
    limit: 50
    unit: concurrent_sessions
    notes: Maximum simultaneous WebSocket connections for Pro tier accounts. Enterprise limits are negotiated.

  - name: Monthly Usage Cap (Free)
    scope: account
    plan: Free
    type: quota
    limit: 20
    unit: hours
    period: monthly
    notes: Maximum real-time transcription hours per month for Free tier.

  - name: Monthly Usage Cap (Pro)
    scope: account
    plan: Pro
    type: quota
    limit: 6000
    unit: hours
    period: monthly
    notes: Maximum real-time transcription hours per month for Pro tier. Contact support for higher limits.

  - name: Batch Jobs Rate (Free)
    scope: account
    plan: Free
    type: rate
    limit: 1
    unit: jobs_per_second
    notes: Maximum batch transcription job submissions per second for Free tier.

  - name: Batch Jobs Rate (Pro)
    scope: account
    plan: Pro
    type: rate
    limit: 10
    unit: jobs_per_second
    notes: Maximum batch transcription job submissions per second for Pro tier.

  - name: WebSocket Session Duration
    scope: session
    plan: All
    type: duration
    limit: 48
    unit: hours
    notes: A single WebSocket session is automatically terminated after 48 hours of continuous connection.

  - name: WebSocket Idle Timeout (No Audio or Ping/Pong)
    scope: session
    plan: All
    type: timeout
    limit: 3
    unit: minutes
    notes: Sessions with no audio data or ping/pong frames sent for 3 minutes will be automatically closed.

  - name: WebSocket Idle Timeout (No Audio Only)
    scope: session
    plan: All
    type: timeout
    limit: 1
    unit: hours
    notes: If no audio data is sent for 1 hour (even if ping/pong active), the session is terminated.

  - name: WebSocket Audio Buffer
    scope: session
    plan: All
    type: buffer
    limit: 10
    unit: seconds
    notes: The real-time API tolerates no more than 10 seconds of audio data buffered ahead. Excess AddAudio messages are held until buffer capacity is available.

  - name: WebSocket AddAudio Message Queue
    scope: session
    plan: All
    type: buffer
    limit: 500
    unit: messages
    notes: No more than 500 individual AddAudio messages may be queued ahead without receiving AudioAdded acknowledgment.

throttling:
  httpStatusCode: 429
  retryAfterHeader: Retry-After
  notes: >
    HTTP 429 Too Many Requests is returned when rate limits are exceeded on REST
    (Batch/Management) API endpoints. For WebSocket sessions that are auto-terminated
    due to limits, the server sends an in-band error message followed by a WebSocket
    closing handshake with code 1008 (Policy Violation). Clients may reconnect
    immediately after disconnection.