Symptom

When attempting to send an SMS API request, you receive HTTP error 413 Request Entity Too Large.

Applies To

• API Request
• SMS Failure
• HTTP Error 413

Resolution

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, review the API request if any part of the request parameters exceeded the maximum size.

Cause

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