Rate Limits

Molted Email enforces rate limits across three time windows to protect deliverability and prevent abuse.

Rate limit windows

Limits for each window depend on your plan. See Billing & Plans for the full table.

Checking usage

Use the GET /v1/me/usage endpoint to check your current usage:

curl https://api.molted.email/v1/me/usage \
  -H "Authorization: Bearer YOUR_API_KEY"

Response

{
  "monthly": {
    "used": 42,
    "limit": 1000,
    "remaining": 958
  },
  "daily": {
    "used": 12,
    "limit": 200,
    "remaining": 188
  },
  "hourly": {
    "used": 3,
    "limit": 50,
    "remaining": 47
  }
}

What happens when a limit is exceeded

When any window's limit is reached, subsequent send requests are blocked with reason rate_limited:

{
  "requestId": "req_abc123",
  "status": "blocked",
  "reason": "rate_limited"
}

The request is not queued. You must wait for the window to reset or upgrade your plan.

Sends can also be blocked for billing reasons:

• trial_not_activated — the tenant is in trial state and hasn't started a paid trial via Stripe Checkout yet.
• subscription_expired — the tenant's subscription has been cancelled or a payment has failed.

Storage quota

In addition to send rate limits, each plan has a storage quota that limits total message body and attachment storage. When the storage limit is exceeded, attachment uploads are blocked with reason storage_limit_exceeded:

{
  "statusCode": 403,
  "message": "Storage limit exceeded. Used: 1073741824 bytes, limit: 1073741824 bytes."
}

Existing data remains accessible. See Storage & Attachments for details on storage limits and retention.

Best practices

• Monitor usage with GET /v1/me/usage before large batch sends.
• Spread sends across hours to avoid hitting hourly limits.
• If you regularly hit limits, consider upgrading your plan.