name: SparkPost API Rate Limits
description: SparkPost applies rate limits to protect service stability. HTTP 429 is returned when limits are exceeded. Daily and monthly sending quotas apply separately from per-endpoint API rate limits.
specificationVersion: "0.1"
url: https://support.sparkpost.com/docs/faq/daily-and-monthly-quota-limits
rateLimits:
  - name: API Endpoint Rate Limit
    description: General rate limit applied to most SparkPost API endpoints. Applies to all endpoints except Transmissions POST.
    scope: account
    limit: null
    window: null
    notes: Specific numeric limits not publicly documented. On 429 response, wait 1 to 5 seconds before retrying.
    errorCode: 429
    retryGuidance: Wait 1 to 5 seconds after receiving HTTP 429 before retrying. Use webhooks as an alternative to polling-heavy patterns.
    exemptions:
      - Transmissions API POST requests are not rate-limited in this way
    headers:
      - name: Retry-After
        description: May be returned on 429 responses

  - name: Transmissions DELETE Rate Limit
    description: DELETE requests to the Transmissions API are rate-limited separately from POST requests.
    scope: account
    endpoint: DELETE /api/v1/transmissions/{id}
    notes: Specific numeric limits not publicly documented. Retry after 1 to 5 seconds on 429.
    errorCode: 429

  - name: Daily Sending Quota
    description: Rolling 24-hour sending limit applied to all accounts. New paid accounts start at 1,000 emails/day and increase over the first week based on plan volume. Exceeding the limit causes message rejection (not queuing).
    scope: account
    window: 24h
    windowType: rolling
    limits:
      - plan: Test (Free)
        limit: 100
        unit: emails
        increaseable: false
      - plan: Starter / Paid
        limit: 1000
        unit: emails
        notes: Initial limit for new paid accounts. Grows proportionally over first week.
        increaseable: true
        increaseProcess: Request via Dashboard; reviewed based on sending history and performance
      - plan: Premier / High-Volume
        limit: custom
        unit: emails
        notes: Sending >50k emails/day average requires dedicated IPs and custom bounce/tracking domains plus IP warm-up
    enforcement: reject
    upgradeDelay: Up to one week after plan upgrade for daily limits to update

  - name: Monthly Sending Quota
    description: Monthly sending cap based on plan tier. Paid accounts may send beyond their plan volume up to a monthly limit and are charged an overage rate. Free accounts cannot exceed monthly volume.
    scope: account
    window: calendar month
    windowType: fixed
    limits:
      - plan: Test (Free)
        limit: 500
        unit: emails
        increaseable: false
      - plan: Starter
        limit: 50000
        unit: emails
        increaseable: true
        overage: Charged at overage rate up to monthly cap
      - plan: Premier
        limit: custom
        unit: emails
    enforcement: reject

  - name: Sandbox Domain Lifetime Limit
    description: The sandbox sending domain (sparkpostbox.com) is limited to 5 total emails across the lifetime of an account. Used for API integration testing only.
    scope: account
    limit: 5
    unit: emails
    windowType: lifetime
    notes: Only for development/testing; switch to a verified sending domain for production use