Free ToolGenerator

MIME Boundary Generator

The boundary string in multipart MIME must not appear in any encoded part. This tool generates one that's safe.

What it does

Generates a 32-character random boundary with a recognizable prefix. Returns the full Content-Type header and the boundary delimiter lines.

When to use

Building MIME messages by hand. Debugging a 'boundary appears in body' MIME parser error.

FAQ

Keep going

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

Plain Text Converter

Strips HTML tags, converts <a> to 'text (url)', converts <p> to double newline, converts <li> to '- '.

Outputs different divider styles (thin, thick, dashed, dotted) at configurable widths for use in plain-text email composition.

Wraps encodeURIComponent / decodeURIComponent.

JSON/CSV Converter

JSON array of objects ↔ CSV with auto-detected columns.

Standard case-conversion algorithms with smart handling of short words (Title Case keeps 'a', 'an', 'the' lowercase).

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.

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

Open Rate Checker

Reply Rate Target

DMARC Generator

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.

Articles Free tools Pricing