Regex Tester (JavaScript)
Test JavaScript regular expressions live — highlighted matches, groups and replace preview, entirely on this device.
46 tools in this domain
Text, regex, Markdown and Unicode utilities — test, clean, count and convert content in your browser with nothing uploaded.
Test JavaScript regular expressions live — highlighted matches, groups and replace preview, entirely on this device.
Read someone else's JavaScript regular expression token by token — every group, quantifier and flag spelled out, entirely on this device.
See the shape of a regular expression: branches, loops and groups drawn as a railroad diagram you can download as SVG — entirely on this device.
Browse copy-paste regex patterns — pragmatic and strict variants, CI-verified match tables and six-language usage for each.
The email regex that tells the truth — pragmatic and RFC 5321 strict variants, fifteen CI-verified rows and the live tester preloaded.
The E.164 phone regex pair — an optional-plus gate and the strict international form, with honest libphonenumber advice and live testing.
Octet-accurate IPv4 matching — 999.1.1.1 fails; leading-zero-tolerant and canonical variants with CI-verified rows and the live tester.
A pragmatic http(s) link gate and a strict host-checking variant — CI-verified match rows, six language spellings, live tester preloaded.
The ISO date shape gate plus a range-checking strict variant — honest about calendars, CI-verified, preloaded in the live tester.
Digits-only validation settled — the five-character gate plus a canonical-integer strict variant, CI-verified rows and live testing.
Lookahead password policies explained honestly — 8-plus and strict 12-plus four-class gates, NIST caveats, safe on-device testing.
UUID validation by layout and by meaning — a case-insensitive 8-4-4-4-12 gate plus a version-and-variant strict form, CI-verified.
Full-form and ::-compressed IPv6 matching per RFC 4291 — the library's honest inversion, CI-verified rows, live tester preloaded.
Look up any JavaScript regex construct — syntax, meaning and a worked example whose result this page computes, with the tester right above the table.
Run your own pattern over a whole body of text — replace across it, extract every match, or keep only matching lines, entirely on this device.
Live word, character, sentence and byte counts with platform limit meters — entirely on this device.
Convert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case and more — every variant at once, entirely on this device.
Compare two texts or files side by side or inline — line, word or character granularity — entirely on this device.
Deduplicate any list with explicit case, trim and Unicode options — order preserved, removed lines auditable, entirely on this device.
Sort any list alphabetically, naturally, numerically, by length, or shuffle it — locale-aware and stable, entirely on this device.
Remove, add, join or split line breaks — hard-wrapped paste to flowing text, columns to SQL IN lists — entirely on this device.
Trim, collapse and normalize spaces, tabs, empty lines and invisible characters — entirely on this device.
Reverse any text by characters, words, each line, or line order — grapheme-safe, entirely on this device.
Flip your text upside down or mirror it into copy-paste Unicode for social bios — entirely on this device.
Turn any title into a clean URL slug — language-aware diacritics folding, batch mode with CSV — entirely on this device.
Strip diacritics and punctuation from any text — independent toggles, base letters kept — entirely on this device.
Rank how often each word appears — case-folding, stopword and top-N filters, CSV export — entirely on this device.
Pull every email, URL and phone number out of messy text — dedupe, count and copy each list, entirely on this device.
Write Markdown beside a sanitized live preview with scroll that stays in sync — entirely on this device.
Convert GitHub-flavored Markdown to clean, sanitized HTML with a faithful preview — entirely on this device.
Turn HTML into GitHub-flavoured Markdown — headings, nested lists, code fences and pipe tables — with everything Markdown cannot say named and counted.
Build a GFM table in a visual grid — paste straight from Excel or Google Sheets — entirely on this device.
Turn your headings into a Markdown table of contents — GitHub and GitLab anchor styles side by side, entirely on this device.
Pick the sections a project README needs, order them with the keyboard, and copy the Markdown — entirely on this device.
Design a badge, watch it render here as SVG, and copy the shields.io URL or the ready-to-paste Markdown — nothing is fetched from this page.
Build the README for your username/username repo — sections, badges and stats-card links — previewed entirely on this device.
Type Mermaid diagram text, or paste a whole Markdown file and step through its mermaid fences — the renderer loads only when you ask it to.
Break any string into per-character code points, categories, byte lengths and escapes — entirely on this device.
Paste a character, type U+2014 or search by name, and get its Unicode name, block, script, category and every escape spelling — all on this device.
Turn any text into zalgo — cursed, glitchy Unicode — by stacking combining marks, with up/mid/down intensity and a reproducible seed, entirely on this device.
Turn text into bold, italic, script, circled and fullwidth Unicode styles for social bios and usernames — every style at once, entirely on this device.
Every Emoji 17.0 character, searchable by name, tag or shortcode — click to copy the emoji, its shortcode or its code points, entirely on this device.
Reveal and strip zero-width, bidi and other hidden characters — code point, name and position for every hit, entirely on this device.
Every ASCII code 0–127 with its decimal, hex, octal and binary value, glyph and control-code name — searchable instantly, entirely on this device.
Turn text into big ASCII-art banners with built-in monospace fonts — entirely on this device.
Paste a number, pick a region, and read every canonical form plus number type and an honest valid-or-possible verdict — parsed entirely on this device.