Content-Type MIME Type Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching content-type mime type, ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// Content-Type MIME Type
// ReDoS-checked | RegexVault — Web & Network > HTTP

package validation

import "regexp"

var contenttypeMimeTypeRe = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9!#$&\-^_]{0,59}/[a-zA-Z][a-zA-Z0-9!#$&\-^_.+]{0,59}(?:;\s*[a-zA-Z][a-zA-Z0-9\-]{0,49}=[^;\s]{1,100})*$`)

func ValidateContenttypeMimeType(s string) bool {
    return contenttypeMimeTypeRe.MatchString(s)
}

// Example
// fmt.Println(ValidateContenttypeMimeType("application/json")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > HTTP category and has been checked for ReDoS risk. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Parameters use name=value format separated by semicolons. The charset parameter is the most common. IANA maintains the media type registry.