Message-ID Tool
Generate and validate RFC 5322 Message-ID header values.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
Generate Message-ID
Generated Message-IDs
Validate Message-ID
Validation results
How it works
Generate RFC 5322 Message-ID header values with user-specified domain. The left side is a unique token using cryptographic randomness; choose timestamp-plus-random or plain random format. Validate existing Message-IDs for correct syntax: angle brackets, single @, valid characters in both the left (dot-atom-text) and right (dot-atom-text domain or bracketed literal) parts. Line length, brackets, forbidden characters, and whitespace are reported with severity (error/warning/info) and stable codes. This tool does not infer a mail server or software from a Message-ID — that is not possible reliably.