Quick question about Web Messaging SDK file uploads. I am sending a 50KB PNG via the guest API but getting a 413 Payload Too Large error.
The docs state: “Maximum file size is 10MB for standard messaging.” My code uses standard HttpClient with multipart/form-data.
The request headers include the correct Authorization token and Content-Type. No custom size limits are set in the engagement configuration.
Why does the SDK reject this valid MIME type and small size? Here is the C# snippet causing the issue:
This looks like a configuration mismatch in the API gateway rather than an SDK limitation. The documentation states, “The maximum file size is determined by the engagement channel configuration, not the global tenant limit.”
Verify the specific channel settings.
- Navigate to Admin > Channels > Messaging > [Your Channel] > Settings.
- Check the “Maximum attachment size” field. It may be overridden to a lower value (e.g., 10KB) for this specific channel.
- Ensure the
Content-Type header is exactly multipart/form-data; boundary=----WebKitFormBoundary.... The SDK generates the boundary automatically. Do not set it manually.
If the channel limit is correct, check the Nginx or AWS ALB configuration in front of the API. A 413 error often originates from the reverse proxy rejecting the body before it reaches the Genesys Cloud application layer. The documentation notes, “Proxy servers may enforce stricter limits than the application.”
Review the proxy logs for client_max_body_size directives.