All Tools
Free ToolGenerator

RFC 5322 Message-ID Generator

Building an MTA or a programmatic sender? Every outbound message needs a unique Message-ID; this tool gives you a spec-compliant one.

What it does

Generates Message-ID in the form <random-id@your-domain>. Validates the format. Explains why both halves matter (uniqueness and routing).

When to use

Building a sending system from scratch. Diagnosing duplicate-Message-ID problems in an existing system.

FAQ

Can I just use a UUID?+

Yes, with @your-domain appended. UUID v4 plus your sending domain is RFC-compliant and globally unique.

Keep going

Articles, glossary entries, and other tools on the same topic.

Free tool
Plain Text Converter
Strips HTML tags, converts <a> to 'text (url)', converts <p> to double newline, converts <li> to '- '.
Open
Free tool
ASCII Dividers
Outputs different divider styles (thin, thick, dashed, dotted) at configurable widths for use in plain-text email composition.
Open
Free tool
URL Encoder
Wraps encodeURIComponent / decodeURIComponent.
Open
Free tool
JSON/CSV Converter
JSON array of objects ↔ CSV with auto-detected columns.
Open
Free tool
Case Converter
Standard case-conversion algorithms with smart handling of short words (Title Case keeps 'a', 'an', 'the' lowercase).
Open
Free tool
From Headers
Reference page with worked examples: a forwarded email, a marketing platform send, a bounce, and a phishing attempt — each annotated to show what's in From vs Return-Path and which checks pass.
Open

Record generated. Now make sure it actually passes on real sends.

A correct DNS record on paper still fails 12% of the time at the receiver. Outsolvi watches every send and flags auth failures, opens that look like proxies, and bounces in real time. From $7/user/mo yearly.

Verify on a real send

Other free tools

Calculator
ROI Calculator
Calculator
MPP Impact
Calculator
Open Rate Checker
Calculator
CPM Calculator
Calculator
Reply Rate Target
Calculator
Sales Cycle
Generator
SPF Generator
Generator
DMARC Generator
Generator
UTM Builder
See all 100 tools
Nate SummersCo-Founder, Outsolvi

Nate built Outsolvi after watching every email-tracking tool he had ever used lie to him about opens. Outsolvi runs Tier 1 to 5 confidence scoring on every open, native in Outlook and Gmail, so the number on the dashboard is one a rep can actually act on.

Last reviewed May 25, 2026Editorially independent

We update these pages when the underlying mechanics change — new mailbox-provider rules, new tracker behavior, new measurement gaps. The dates above are real revisions, not auto-touches.

ArticlesFree toolsPricing