Rate limits and quotas

MailerDash enforces two types of limits on sends: a per-minute rate limit (rate_per_min) and a monthly quota (monthly_quota). Both are defined at the plan (package) level and can have per-account overrides configured by the MailerDash team.

---

Rate limit (rate_per_min)

Controls how many send requests your API key can make within a 60-second window. If you exceed this limit, the API responds with HTTP 429.

The default for accounts without an assigned plan is 30 requests/minute. Your plan may grant a higher limit.

{
  "error": {
    "type": "rate_limit_error",
    "code": "rate_limit_exceeded",
    "message": "Too many requests. Please slow down."
  }
}

The response includes the standard rate limit headers:

Header	Description
RateLimit-Limit	Maximum number of requests in the window
RateLimit-Remaining	Requests remaining in the current window
RateLimit-Reset	Unix timestamp when the window resets

Tip

Implement a retry mechanism with exponential backoff in your integration to absorb traffic spikes without losing sends. When you receive a 429, wait at least until the time indicated by RateLimit-Reset before retrying.

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Monthly quota (monthly_quota)

The maximum number of emails you can send in a billing period (month). The counter resets at the start of each new period.

When you reach your monthly quota, additional sends are rejected with HTTP 429:

{
  "error": {
    "type": "rate_limit_error",
    "code": "monthly_quota_exceeded",
    "message": "Monthly quota exceeded: 5000/5000 emails sent this month"
  }
}

Overage

If your plan includes it, you can continue sending after exhausting your base quota by paying per additional email (overage). If the plan does not offer overage, sends that exceed the quota will be blocked with the code overage_not_offered.

---

Check your current usage

GET /v1/client/usage
Authorization: Bearer $MAILERDASH_API_KEY

This endpoint returns the usage for the current period for each API key linked to your account, along with the limits of the active plan:

{
  "subscriptions": [
    {
      "package_id": "pro",
      "package_name": "Pro",
      "monthly_quota": 50000,
      "rate_per_min": 120,
      "billing_period": "monthly",
      "started_at": "2026-06-01T00:00:00.000Z"
    }
  ],
  "keys": [
    {
      "id": "mi-key",
      "label": "Producción",
      "sent_this_period": 12340,
      "monthly_quota": 50000,
      "quota_remaining": 37660
    }
  ],
  "next_reset": "2026-07-01T00:00:00.000Z"
}

The next_reset field indicates when the monthly counter will reset.

---

Payload limits

In addition to rate and quota limits, there are limits on request size:

• Attachments: if the total attachments exceed the allowed limit, you will receive a 413 with code payload_too_large. The param field will indicate attachments.

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Summary of related error codes

code	HTTP	Description
rate_limit_exceeded	429	You exceeded the per-minute request limit
monthly_quota_exceeded	429	You exceeded your plan’s monthly quota
overage_not_offered	400	The plan does not allow extra sends after the quota is exhausted
payload_too_large	413	The request body exceeds the maximum size

See the full reference at /reference/platform/ and error handling at /en/reference/errors/.