Free Developer tools

Tool

JSON Formatter & Validator

Format, beautify, minify and validate JSON in your browser. Errors show the exact line and column, with sort keys, a collapsible tree view, copy and download.

Open Tool

JSON to YAML Converter

Convert JSON to YAML and YAML to JSON in your browser. Choose 2 or 4 space indents, handle multi-document YAML and see errors with the exact line and column.

Open Tool

CSV to JSON Converter

Convert CSV to JSON and JSON to CSV in your browser. Handles quoted fields, auto-detects commas, semicolons and tabs, detects numbers and previews a table.

Open Tool

XML Formatter & Validator

Format, minify and check XML in your browser. Errors show the line and column, comments and CDATA are kept, and an XPath tester lets you query the document.

Open New Tool

XML to JSON Converter

Convert XML to JSON and JSON to XML in your browser. Set attribute and text keys, arrays and namespaces, see errors by line and column, then copy or download.

Open Tool

SQL Formatter

Format SQL for MySQL, PostgreSQL, SQL Server, SQLite and standard SQL. Choose keyword case and indentation, then copy or download. Queries are never run.

Open Tool

Code Beautifier (HTML, CSS, JavaScript)

Beautify minified or messy HTML, CSS and JavaScript in your browser. Choose 2 or 4 spaces or tabs, line wrapping and brace style, then copy or download it.

Open Tool

HTML, CSS & JavaScript Minifier

Minify CSS, HTML, JavaScript and JSON in your browser. See original and minified size, the percentage saved and an estimated gzip size. Nothing is uploaded.

Open Tool

HTML Viewer & Live Editor

Paste HTML and see it rendered live in a sandboxed preview. Switch JavaScript off, check mobile, tablet and desktop widths, and download your page as a file.

Open Tool

Markdown to HTML Converter

Convert Markdown to clean HTML with GitHub Flavoured Markdown tables, task lists and code blocks, a sanitised live preview, and HTML back to Markdown too.

Open Tool

Base64 Encode & Decode

Encode and decode Base64 with full UTF-8 support, a URL-safe option, file to Base64 or data URI conversion, and Base64 back to a downloadable file.

Open Tool

URL Encoder / Decoder

Percent-encode or decode text and URLs with encodeURIComponent, encodeURI or form mode. Spots malformed sequences and splits any URL into editable parts.

Open Tool

JWT Decoder

Decode a JSON Web Token to read its header and payload, see exp, iat and nbf as real dates with expiry status, and verify HS256, HS384 or HS512 signatures.

Open Tool

Hash Generator (MD5, SHA-256…)

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files, in hex or Base64, with HMAC and checksum matching. Nothing is uploaded.

Open Tool

UUID Generator

Generate random v4 or time-ordered v7 UUIDs, 1 to 1,000 at a time, in upper or lower case, with or without hyphens. Check any UUID's version too.

Open Tool

Unix Timestamp Converter

Convert Unix timestamps to dates and back. Live epoch time, auto-detects seconds, ms and µs, and shows UTC, UK time (GMT/BST), ISO 8601 and RFC 2822.

Open Tool

Regex Tester

Test JavaScript regular expressions with live match highlighting, capture and named groups, flags, replace preview, a cheat sheet and UK-ready patterns.

Open Tool

Cron Expression Generator

Build or paste a cron expression and see it in plain English with the next 10 run times in your time zone and UK time, plus Laravel and GitHub Actions code.

Open Tool

htaccess Redirect Generator

Generate Apache .htaccess rules for 301 and 302 redirects, bulk URL lists, force HTTPS, www, trailing slashes and domain moves, with loop and chain warnings.

Open Tool

CSS Gradient Generator

Create linear, radial and conic CSS gradients with draggable colour stops, opacity, presets and OKLCH blending. Live preview and copy-ready CSS with fallbacks.

Open Tool

CSS Box Shadow Generator

Design layered CSS box shadows with offset, blur, spread, colour, opacity and inset. Soft, elevated and neumorphic presets. Copy CSS or a Tailwind class.

Open Tool

PX to REM Converter

Convert px to rem and em with any root font size. See a table of common sizes with Tailwind values, and bulk convert pasted CSS while keeping 1px borders.

Open Tool

Colour Converter & Contrast Checker

Convert colours between HEX, RGB, HSL, HWB and CMYK, build tints and shades, and check WCAG 2.2 colour contrast for AA and AAA with a live preview.

Also in Images & design Open Tool

Image to Base64 Converter

Convert images to Base64 as a data URI, raw string, CSS background or HTML img tag, with the size overhead shown. Decode Base64 back to an image too. No upload.

Also in Images & design Open New Tool

Subnet Calculator

Free IPv4 and IPv6 subnet calculator: network, broadcast, host range, masks, address type and reverse DNS. Split, VLSM, summarize routes and export to CSV.

Also in Domain & DNS Open Tool

Content Security Policy Generator

Build a Content-Security-Policy header with presets for Google Analytics, Google Fonts, YouTube and Stripe. Report-only mode and Nginx, Apache and meta tag output.

Also in Security & SSL Open