name: GOV.UK Notify Rate Limits
description: Rate limits and daily send quotas for the GOV.UK Notify API.
url: https://docs.notifications.service.gov.uk/rest-api.html
rate_limits:

  - name: Per-Minute Throughput Limit
    description: Maximum number of messages that can be sent per minute per API key type (rolling window).
    limit: 3000
    period: minute
    unit: messages
    scope: per_api_key_type
    error_code: 429
    error_type: RateLimitError
    notes: Applied per API key type (test, team/guest list, or live). Limit is calculated on a rolling basis.

  - name: Daily SMS Limit
    description: Maximum number of SMS text messages that can be sent in a single day.
    limit: 250000
    period: day
    unit: text messages
    error_code: 429
    error_type: TooManyRequestsError
    notes: Includes 100 international messages by default.

  - name: Daily Email Limit
    description: Maximum number of emails that can be sent in a single day.
    limit: 250000
    period: day
    unit: emails
    error_code: 429
    error_type: TooManyRequestsError

  - name: Daily Letter Limit
    description: Maximum number of letters that can be sent in a single day.
    limit: 20000
    period: day
    unit: letters
    error_code: 429
    error_type: TooManyRequestsError

  - name: Phone Network Identical Messages
    description: Maximum identical messages sent to the same phone network per hour.
    limit: 20
    period: hour
    unit: identical messages
    scope: per_phone_network
    notes: Prevents spam patterns on any single phone network.

  - name: Phone Network Any Content
    description: Maximum messages of any content sent to the same phone network per hour.
    limit: 100
    period: hour
    unit: messages
    scope: per_phone_network

  - name: JWT Token Expiry
    description: API authentication tokens expire within 30 seconds to prevent replay attacks.
    limit: 30
    period: seconds
    unit: JWT token lifetime
    error_code: 403
    error_type: AuthError
    notes: Server clock must be within 30 seconds of UTC or authentication will fail.

  - name: Notification List Page Size
    description: Maximum number of notifications returned per page when listing messages.
    limit: 250
    period: request
    unit: notifications per page

  - name: Received Text Messages Page Size
    description: Maximum number of received text messages returned per page.
    limit: 250
    period: request
    unit: received texts per page

  - name: File Upload Size
    description: Maximum file size for email attachments and precompiled letters.
    limit: 2
    period: request
    unit: MB

  - name: Letter Pages
    description: Maximum number of pages in a single letter.
    limit: 10
    period: letter
    unit: pages
    notes: Equivalent to 5 double-sided sheets in a C5 envelope.