Why is my API Request Receiving an HTTP Error 413?


  • Why is my API request receiving an HTTP error 413?
  • Why am I getting 413 Request Entity Too Large errors?
  • What is the maximum API request size?
  • Is there an API request size limit or cap?


If you are experiencing SMS send failures with status code "413 Request Entity Too Large", this is due to an oversized API request.

We cap the maximum request size at 4000 characters for all of the APIs (and at 8000 for TTS), to protect our platform from potential attacks overwhelming our backend. When getting this error, please review the API request if any part of the request parameters exceeded the maximum size.

Please feel free to contact us via email to or our support portal at if you have any further questions.

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