Regex Tester
Build, test and understand regular expressions as you type.
Private: your files never leave your device.
How it works
- Choose your files.
- Adjust the settings if you like.
- Download the result, or send it to another device with BroAllDone.
Frequently asked questions
How do I test a regular expression?
Type the expression and some text: every match is highlighted as you type, with a table of matches and their groups.
What do the flags g, i, m, s, u and y mean?
g finds every match, i ignores case, m makes ^ and $ work on each line, s lets . match line breaks, u turns on full Unicode, and y matches only where the last match ended.
Can it explain what an expression does?
Yes. Open Explanation to see each part of the expression in plain words, like "a digit, exactly 4 times".
Can I test a replacement?
Yes. Open Replace and type the replacement: use $1 for a group, $<name> for a named group and $& for the whole match.
Which regex flavour is this?
JavaScript, as in browsers and Node.js. Code shows the expression ready to use in JavaScript, Python, PHP, Java, C# and Go, and warns when a language lacks a feature.
Why was my expression stopped?
Some expressions take forever on certain text (catastrophic backtracking). The tester stops them after a moment, so the page never freezes; try a more specific pattern.
More free tools
- QR Code Generator Type a link, some text or your Wi-Fi details and get a QR code instantly.
- Resize Images Shrink photos to a smaller file size or new dimensions, right in your browser.
- Convert WebP to JPG or PNG Convert WebP pictures into JPG or PNG, so they open on any device and app.
- Images to PDF Put your photos or screenshots into a single PDF, in the order you want.
- Scan to PDF Photograph each page with your phone, and get one tidy PDF.
- Merge PDF Join PDF files into one document, in any order you like.
- Split PDF Take out the pages you need, or save every page as a separate PDF.
- Compress PDF Shrink big PDFs so they're easier to email and upload.
- Convert HEIC to JPG Open iPhone photos anywhere: convert HEIC to JPG or PNG in your browser.
- Video to MP3 Save the audio from a video as an MP3 file, right in your browser.
- Image Upscaler Make small pictures bigger and sharper with AI, without uploading them.
- Convert JPG to PNG Convert JPG pictures to PNG in your browser.
- Convert PNG to JPG Convert PNG images to JPG in your browser.
- Convert JPG to WebP Convert JPG photos to WebP for faster websites.
- Convert HEIC to PNG Convert iPhone HEIC photos to PNG in your browser.
- Convert AVIF to JPG Convert AVIF pictures to JPG in your browser.
- Convert SVG to PNG Convert SVG files to high-quality PNG images.
- Compress Image to KB or MB Shrink a photo to the exact size a form asks for.
- Passport Photo Maker Crop your photo to an official passport size, then print it at home or in a shop.
- ID Photo Resizer Make ID photos in standard sizes, ready to print or upload.
- PDF to Word Turn a PDF into a Word document you can edit.
- Word to PDF Turn a Word document into a PDF that looks the same everywhere.
- PDF to Excel Turn the tables in a PDF into an Excel spreadsheet.
- Excel to PDF Turn a spreadsheet into a PDF.
- PDF to PowerPoint Turn a PDF into PowerPoint slides.
- PowerPoint to PDF Turn a presentation into a PDF.
- HTML to PDF Turn a saved web page or HTML file into a PDF.
- Background Remover Cut out people, products and objects from their background.
- Delete PDF Pages Remove the pages you don't need from a PDF.
- PDF to JPG or PNG Save the pages of a PDF as images.
- Watermark PDF Add a text or logo watermark to every page.
- Protect PDF with a Password Lock a PDF with a password.
- Remove EXIF & Photo Metadata Remove the hidden location and camera data from your photos.
- Image to Text (OCR) Get the text from a picture, ready to copy.
- Edit PDF Add text, pictures, highlights and white-out to any PDF.
- Sign PDF Put your signature on a PDF in seconds.
- PDF Page Numbering Number the pages of any PDF, exactly where you want them.
- Convert DNG to JPG Develop RAW DNG photos into JPGs that open everywhere, right in your browser.
- Image Watermark Protect your photos with your name or logo, in seconds.
- Convert TIFF to JPG or PNG Convert TIFF files, including multi-page scans, to JPG or PNG.
- Convert GIF to JPG or PNG Convert GIF pictures to JPG or PNG in your browser.
- Convert BMP to JPG or PNG Convert BMP pictures to JPG or PNG in your browser.
- Image to Base64 Turn a picture into Base64 text you can paste into code.
- Base64 to Image Turn Base64 text back into a picture you can see and download.
- Convert PSD to JPG or PNG View and convert Photoshop files without Photoshop.
- Convert EPS to JPG or PNG Turn EPS artwork into a JPG or PNG that opens everywhere.
- PDF Page Rotator Turn sideways or upside-down pages the right way up.
- Unlock PDF Remove a PDF's password and restrictions.
- PDF Metadata Editor Change or remove the hidden details stored in a PDF.
- Remove Blank Pages from PDF Find the empty pages in a PDF and take them out.
- PDF to Text Get the text out of a PDF, ready to copy or save.
- Extract Images from PDF Pull the photos and pictures out of a PDF.
- PDF Header & Footer Put a title, date or page numbers at the top and bottom of every page.
- Compare PDFs Find every difference between two versions of a document.
- Redact PDF Hide private information in a PDF so it can't be recovered.
- PDF Bates Numbering Number every page of a document set for legal and audit work.
- Text to PDF Make a tidy PDF from plain text, in any language.
- Crop PDF Trim pages down to just the part you need.
- PDF N-up & Booklet Save paper with several pages per sheet, or make a folded booklet.
- JSON Formatter Make JSON readable, find mistakes, or squeeze it onto one line.
- XML Formatter Make XML readable, find mistakes, or squeeze it onto one line.
- HTML Beautifier & Minifier Tidy up HTML, or make it as small as it can safely be.
- CSS Beautifier & Minifier Tidy up CSS, or make it as small as it can safely be.
- JavaScript Beautifier & Minifier Tidy up JavaScript, or make it as small as it can safely be.
- SQL Formatter Make SQL readable, in the keyword style you like, or squeeze it onto one line.
- JSON to CSV Turn JSON data into a spreadsheet you can open in Excel.
- CSV to JSON Turn a spreadsheet export into JSON for your code.
- JSON to YAML Turn JSON into YAML that is easy to read.
- YAML to JSON Turn YAML config into JSON.
- YAML Validator & Formatter Check YAML for mistakes and give it clean, even indentation.
- XML to JSON Turn XML data into JSON for your code.
- JSON to XML Turn JSON into clean, valid XML.
- Base64 Encode & Decode Turn text or files into Base64, or Base64 back into text or files.
- URL Encode & Decode Make text safe for links, or read encoded links.
- JWT Decoder Read what's inside a JWT and check that it's genuine.
- Hash Generator Fingerprint text or files, and check downloads against their checksum.
- HMAC Generator Sign a message with a secret key, or check a webhook signature.
- UUID Generator Make unique IDs for databases and code, in the version you need.
- Password Generator Make strong passwords you can trust, right on your device.
- Image DPI Converter Set the resolution for printing, without touching the pixels.
- SVG Optimizer Shrink SVG files and code, safely, with a before-and-after check.
- Favicon Generator Turn a logo, a letter or an emoji into a complete favicon set.
- Image Color Picker Find the exact colour of any pixel, and a picture's main colours.
- JPG & PNG to TIFF or BMP Make TIFF and BMP files from any image, or turn TIFF and BMP into PNG and JPG.
- JSON to TypeScript Get accurate TypeScript types from any JSON in one click.
- JSON Schema Generator Describe your JSON with a schema you can validate against.
- cURL to Code Paste a curl command and get code that's ready to run.
- Text Case Converter Every case, from Title Case to snake_case, in one place.
- Online API Tester Test any REST API from your browser: build a request, send it and inspect the answer.
- Unix Timestamp Converter Turn epoch time into readable dates and back, in any time zone.
- JSONPath Tester Paste JSON, write a JSONPath expression and see what it selects.
- Cron Expression Generator & Explainer Create, read and check cron schedules, and see when they run next.
- Text & Code Diff Checker Paste two versions and see exactly what changed.
- OCR PDF Turn scans into PDFs you can search, select and copy.
- Organize PDF Pages Put your pages in the right order and keep only the ones you need.
- Repair PDF Recover everything that can still be read from a broken PDF.
- Bulk Image Compressor Make a whole batch of pictures smaller in one go.
- Image Cropper Crop, straighten and size pictures exactly the way you need them.
- Fancy Text Generator Type your text and copy it in bold, cursive, bubble, gothic and many more styles.
- Social Media Image Resizer Pick the platforms and get your photo in every size they need, all at once.
- Profile Picture Maker Turn any photo into a round profile picture, with a ring or border if you like.
- YouTube Thumbnail Downloader Paste a YouTube link and save its thumbnail in every size, up to HD.
- WhatsApp Link Generator Make a link that opens a WhatsApp chat with you in one tap, with a QR code.
- Invisible Text Generator Copy a blank character for an empty name, message or bio, or find hidden ones in text.
- Instagram Carousel Splitter Cut one wide photo into seamless carousel slides or a profile grid.
- YouTube Thumbnail Resizer & Preview Size any picture into a perfect YouTube thumbnail and see how it looks before you upload.
- Hashtag Formatter Turn words into clean, ready-to-paste hashtags and check each platform's limit.
- Engagement Rate Calculator See your engagement rate for one post or many, and how it compares with accounts your size.
- UTM Link Builder Tag your links with UTM parameters to see which posts and campaigns bring visitors.
- Caption Formatter Make your post captions look great and see exactly how each app will show them.
- SRT to VTT Converter Turn SRT subtitle files into WebVTT for web video players, keeping their formatting.
- VTT to SRT Converter Turn WebVTT subtitle files into SRT that works in every player and editor.
- Subtitle Fixer & Formatter Put subtitles back in sync and clean them up, with a report of every fix.