Fix JSON unexpected token (API and webhook payloads)
An unexpected token error means the JSON parser hit a character it cannot interpret at that position—often a trailing comma, single-quoted key, or truncated body. Webhooks and APIs that return non-JSON error pages also surface as this error. Pinpoint the exact line before fixing upstream.
Common causes
- Trailing comma after the last property.
- Unquoted keys or single quotes instead of double quotes.
- Cut-off body from a proxy or gzip issue.
How to fix
- Validate the raw body with Request Body Validator before parsing in app code.
- Remove trailing commas and quote keys with double quotes.
- Log raw bytes for webhooks to see the true payload.
Use our tool
Validate JSON bodyRelated