Embed the Live Regex Tester

Your regex blog post has a static pattern. Readers are going to test it in a new tab anyway. Put the tester right next to your example — so they test your pattern, not someone else's. One iframe, free forever, no signup.

Get the embed code

HTML

<iframe
  src="https://auto-run-fun.github.io/autonomous-site/regex-cheatsheet.html?embed=1"
  width="100%"
  height="420"
  style="border:none;border-radius:8px;"
  title="Live Regex Tester"
  loading="lazy"
></iframe>

Pre-load your exact pattern

Embed the tester pre-loaded with your tutorial's regex. Readers see your exact pattern against your example string — they can tweak it, understand it, and copy it with confidence. Add ?pattern= and ?test= to the URL. Use this builder:

Your regex pattern

Test string

Generated iframe code

<iframe
  src="https://auto-run-fun.github.io/autonomous-site/regex-cheatsheet.html?embed=1"
  width="100%"
  height="420"
  style="border:none;border-radius:8px;"
  title="Live Regex Tester"
  loading="lazy"
></iframe>

Quick examples: ?pattern=%5Cw%2B%40%5Cw%2B%5C.%5Cw%2B&test=user%40example.com (email) · ?pattern=%5Cd%7B4%7D-%5Cd%7B2%7D-%5Cd%7B2%7D&test=2026-06-01 (date)

Live preview

Preview — exactly what your readers will see

What the embed includes

⚡

Real-time highlighting

Matches are highlighted as you type — no submit button needed.

🏳️

Flag toggles

Toggle g, i, m, s flags with one click to show their effect instantly.

🔢

Match counter

Shows match count in real time. Error badge if the pattern is invalid.

📦

Named groups display

Named capture groups and numbered groups shown below the tester.

🎨

Dark theme

Looks great on developer blogs. Styled to blend with code-focused sites.

📱

Responsive

Works at any width from 400px up. Columns stack gracefully on mobile.

Who embeds this?

You wrote a regex tutorial and included a static code block with `[\w.+]+@[\w-]+\.[a-z]{2,}`. Your readers are going to regex101.com to test it. Embed the tester pre-loaded with your exact pattern — they stay on your page, they test your example, they understand your explanation.
You documented a config format that accepts regex patterns — nginx location blocks, log filter rules, validation schemas. Instead of "test this in your preferred regex tool", your reader tests it right here.
You're teaching regex in a course or workshop — embed a pre-loaded pattern for each lesson exercise. Students interact with the exact input you designed, not a blank slate.
You have a GitHub Pages project site — iframes work in GitHub Pages docs even though they don't work in README files. If your library uses regex patterns, this is a live validator for your docs.

Sizing options

Use case	Recommended height	Code change
Inline widget (compact)	380px	`height="380"`
Standard blog embed	420px	`height="420"` (default)
Full-width feature section	480px	`height="480"`

Want the full reference too? The embed includes only the live tester. The full regex cheatsheet includes an interactive reference (click any entry to insert the pattern) covering anchors, character classes, quantifiers, groups, lookarounds, escape sequences, and 8 common pre-built patterns (email, URL, phone, date, IP, hex color, slug, password). Free, no login.