Webhook payload invalid JSON: find the parse break
Providers send JSON bodies; if your receiver logs show invalid JSON, the issue may be middleware altering the body, wrong encoding, or an error page returned as HTML. Inspect the raw payload before signature verification when possible.
Common causes
- Body parsed as JSON before HMAC verification (wrong message).
- Proxy or WAF returning HTML error page.
- UTF-8 BOM or null bytes at the start.
How to fix
- Use Webhook Payload Viewer to format and eyeball structure.
- Validate with Request Body Validator on the exact raw string.
- Verify raw bytes match what the provider signed.
Use our tool
Open Webhook Payload ViewerRelated