Rate limits, restrictions and API errors

Rate limiting

By default, standard accounts are limited to a certain number of requests per second (displayed in Settings > API > Limits). Beyond that, the API returns an error 429 Too Many Requests. High volume accounts may request an increase in this limit.

Common HTTP response codes

• 200 OK — request processed successfully
• 400 Bad Request — missing or malformed parameter (e.g. invalid number)
• 401 Unauthorized — API key missing or invalid
• 402 Payment Required — insufficient balance
• 429 Too Many Requests — rate limit exceeded
• 500 Internal Server Error — platform side error, contact support with request ID

Best practices

• Implement retry logic with exponential backoff on errors 429 and 500
• Systematically log the returned message_id to facilitate any future diagnosis
• Use sandbox mode to test your integration without consuming real credits or sending real messages