Running into a wall with the Digital First Omnichannel API for custom messaging. We’re trying to allow customers to upload support docs via our web widget. The endpoint is POST /api/v2/digital/interactions/{interactionId}/messages.
The payload structure matches the spec:
{
"media": [
{
"filename": "manual.pdf",
"mimeType": "application/pdf",
"content": "BASE64_STRING_HERE"
}
]
}
Small text files go through fine. But as soon as the base64 string hits around 2.5MB (which is a tiny PDF), the server throws a 413 Payload Too Large. The documentation explicitly states the limit is 5MB for application/pdf.
I’ve checked our Nginx config on the origin server, client_max_body_size is set to 10m. We’re not hitting a network timeout. It feels like the DFO API has a hidden or stricter limit than advertised, or maybe the base64 encoding overhead is being counted against the limit before decoding?
Has anyone pushed a 3MB+ file through this specific endpoint? Or is there a chunking mechanism I’m missing?