Rate limits

Brixus365 enforces two kinds of limits: per-minute request limits (preview accounts only) and monthly send quotas (all accounts). Both return HTTP 429 with a Retry-After header. See Errors for the full error envelope shape.

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Response headers

On preview-account requests, every API response includes rate-limit headers:

Header	Type	Description
X-RateLimit-Limit	integer	Maximum requests allowed in the current window.
X-RateLimit-Remaining	integer	Requests remaining before you hit the limit.
X-RateLimit-Reset	unix timestamp	UTC timestamp when the current window resets.
X-RateLimit-Window	integer	Window duration in seconds.

These headers reflect the per-minute window. Full accounts do not enforce per-minute limits and do not receive these headers.

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Send limits

Account type	Per-minute	Daily	Monthly
Preview account (bx_test_* key)	10 requests	50 emails	1,500 emails
Free account	—	—	9,000 emails
Paid plans	—	—	See Pricing

Preview accounts are created via the sign-up API for quick evaluation. Create a free account to lift the per-minute and daily limits.

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Per-minute rate limit

Preview accounts are limited to 10 requests per minute per API key. When exceeded:

HTTP/1.1 429 Too Many Requests
Content-Type: application/json
Retry-After: 47
X-RateLimit-Limit: 10
X-RateLimit-Remaining: 0
X-RateLimit-Reset: 1746458820
X-RateLimit-Window: 60

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests. Try again in up to 1 minute.",
    "type": "rate_limit_error",
    "retry_after_seconds": 47,
    "details": {
      "limit": 10,
      "window_seconds": 60
    }
  }
}

Wait the value of Retry-After (or error.retry_after_seconds) before retrying. The window is 60 seconds; retrying immediately returns another 429.

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Daily send limit

Preview accounts are limited to 50 emails per day. Once the daily limit is reached, wait for the daily reset or create a free account to lift the limit.

{
  "error": {
    "code": "daily_limit_exceeded",
    "message": "Daily limit of 50 emails reached. Upgrade to send more.",
    "type": "rate_limit_error",
    "upgrade_url": "https://brixus365.com/pricing",
    "details": {
      "limit": 50,
      "used": 50
    }
  }
}

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Monthly send quotas

When the monthly limit is reached, the API returns 429 regardless of account type:

{
  "error": {
    "code": "monthly_limit_exceeded",
    "message": "Monthly limit of 9000 emails reached.",
    "type": "rate_limit_error",
    "upgrade_url": "https://brixus365.com/pricing",
    "details": {
      "limit": 9000,
      "used": 9000
    }
  }
}

Monthly quotas reset on the first day of each calendar month.

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Handling rate limits in code

Honour Retry-After for per-minute limits; distinguish quota exhaustion (which requires a plan upgrade, not a wait):

import time
import requests

def send_with_retry(api_key, payload, max_retries=3):
    for attempt in range(max_retries):
        resp = requests.post(
            "https://app.brixus365.com/api/v1/emails/send",
            headers={"X-API-Key": api_key},
            json=payload,
        )
        if resp.status_code != 429:
            resp.raise_for_status()
            return resp.json()

        err = resp.json().get("error", {})
        code = err.get("code")

        if code in ("daily_limit_exceeded", "monthly_limit_exceeded"):
            raise RuntimeError(
                f"Send limit reached — upgrade at {err.get('upgrade_url')}"
            )

        wait = int(resp.headers.get("Retry-After", 60))
        if attempt < max_retries - 1:
            time.sleep(wait)
            continue

    raise RuntimeError("Rate limit retries exhausted")

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What’s next

You want to…	Go to
See every error code with description and suggested action	Error codes
Understand the error envelope	Errors
Upgrade your account	Pricing