Content-Type troubleshooting

MIME and Content-Type parameter errors

Parameters follow the media type after semicolons. Each parameter needs a valid name and value; malformed quotes, missing values, and duplicates can prevent a Content-Type value from being parsed reliably.

Validate the value before changing code

For example:

application/example; version=2; charset=utf-8

CorrectMIME reports structural parameter problems and can show canonical formatting when the value is safe to normalize. It does not inspect the body or determine a file's MIME type.

Check parameter syntax

Common parameter failures

What canonical formatting can change

When the value can be parsed safely, canonicalization can normalize casing, spacing, parameter names, order, and suitable parameter values. It does not change the underlying content or verify registration with IANA.