# Free HTML & Markdown Tools — Preview, Convert, Share · Comma

Canonical: https://commareports.com/tools
Published: 2026-09-18

> Free browser tools for HTML and Markdown: render an .html file, convert Markdown to HTML, and turn either one into a shareable link with anchored comments. Nothing installs, nothing uploads.

# Free tools

Small, focused browser tools for the moment you have a file and no good way to
show it to anyone. They run entirely on your machine — nothing is uploaded
unless you ask for a link.

## HTML viewer

**[Open the HTML viewer →](/tools/html-viewer)**

Paste HTML or drop an `.html` file and watch it render — CSS, JavaScript and
charts included — in a sandboxed preview at desktop, tablet and mobile widths.
This is the fastest way to check what a build artifact, a coverage report or an
AI-generated page actually looks like before you send it on.

## Markdown to HTML

**[Open the Markdown converter →](/tools/markdown-to-html)**

Paste Markdown or drop a `.md` file and get clean HTML: GitHub-flavored tables,
fenced code blocks, lists, blockquotes and links. Copy the fragment for a CMS or
an email, download a standalone styled page, or publish it as a link. Useful for
the output of an agent run, a meeting summary, or a README you need a non-Git
audience to read.

## Why the link is better than the file

Every tool here ends with the same option: turn what you're looking at into a
Comma report.

- **One URL, not an attachment.** Nobody has to download anything, unzip
  anything, or trust that their machine renders it the same way yours did.
- **Comments anchored in place.** Readers select a paragraph, a table row or a
  chart and comment there, instead of writing "third chart, second bar" in a
  chat thread.
- **Revisions.** Publish again and the old version is kept, so you can see what
  moved between Tuesday and Friday.
- **Access you control.** Private, invite-only, or open to anyone with the link
  — changeable after the fact.

Comma is free: unlimited reports, unlimited commenters, no seat count.

## Related

- [Open an HTML file online](/open-html-file-online) — the article version of the viewer
- [Share an HTML report](/share-html-report) — publishing walkthrough
- [Host an HTML file](/host-html-file) — when you need a URL, not a preview
- [Fix a report with broken CSS](/html-report-broken-css) — assets missing after upload
- [Report types](/report-types) — the publishing guide for every tool that emits HTML