Developer tools

About these tools

All 96 tools in this section are free, work in your browser on any device, and need no sign-up.

• JSON formatter & validator: Format, minify, sort and validate JSON, with the exact line of any error. Big numbers stay exact.
• XML formatter & validator: Pretty-print or minify XML and find errors.
• HTML, CSS & JS beautifier: Make messy or minified HTML, CSS and JavaScript readable again. Formatter.
• CSS minifier: Make CSS files smaller for faster websites (safe structural minification).
• JavaScript minifier: Compress and minify JavaScript with Terser.
• SQL formatter: Format SQL queries for MySQL, PostgreSQL, SQL Server, SQLite, Oracle and more.
• Base64 encoder / decoder: Encode or decode Base64 text and files, including data: URLs.
• JWT decoder: Read the header and payload of a JSON Web Token and check when it expires.
• Regex tester: Test regular expressions live: highlighted matches and capture groups.
• UUID generator: Generate random UUIDs (v4) or time-ordered UUIDs (v7), one or many. GUID.
• Hash generator: MD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or files. Checksum.
• Cron expression helper: Build and understand cron schedules in plain English, with the next run times.
• Unix timestamp converter: Convert Unix timestamps to dates and back, in any time zone. Epoch.
• HTML entity encoder / decoder: Escape special characters like < > & as HTML entities, or decode entities back to text.
• JSON to YAML converter: Convert JSON to YAML and YAML to JSON, for configs, Docker Compose and Kubernetes files.
• JSON to XML converter: Convert JSON to XML and XML to JSON, with attributes kept.
• JSON to TypeScript: Generate TypeScript interfaces from sample JSON, with optional fields and nested types.
• JSONPath tester: Test JSONPath queries ($.store.books[?(@.price < 20)]) against your JSON live.
• JSON diff: Compare two JSON documents and see every added, removed and changed value with its path.
• Query string parser: Break a URL's query string into decoded parameters, or build one from key=value lines.
• UTM link builder: Add utm_source, utm_medium and utm_campaign to links for Google Analytics campaign tracking.
• HTML table generator: Turn CSV or spreadsheet data into a clean HTML table, with a live preview.
• Markdown table generator: Turn CSV into a Markdown table (and back), with column alignment.
• CSV to SQL: Turn CSV into CREATE TABLE and INSERT statements for MySQL, PostgreSQL, SQLite or SQL Server.
• JWT generator: Create and sign JSON Web Tokens (HS256, HS384, HS512) for testing, in your browser.
• HMAC generator: HMAC-SHA256 and other HMAC signatures of a message, as hex or Base64.
• Bcrypt hash generator: Hash passwords with bcrypt and check a password against a hash.
• ULID generator: Generate sortable ULIDs and decode the time inside one.
• Nano ID generator: Short, URL-safe random IDs of any length and alphabet.
• Base32 and Base58 encoder: Encode and decode Base32, Base58 (Bitcoin), Base64URL and hex.
• Punycode converter: Convert international domain names (Arabic, Chinese…) to xn-- punycode and back.
• String escape and unescape: Escape or unescape text for JSON, JavaScript, SQL, CSV, HTML, regex and URLs.
• SVG optimizer: Make SVG files smaller: remove editor data, comments, metadata and extra decimals.
• SVG to data URI: Turn an SVG into a data URI for CSS backgrounds or <img> tags.
• SQL minifier: Remove comments and extra spaces from SQL queries, keeping strings intact.
• Line ending converter: Convert files between CRLF (Windows), LF (Linux, macOS) and CR line endings.
• Tabs to spaces converter: Convert tabs to spaces (or leading spaces to tabs) with any tab width.
• File encoding converter: Fix garbled text (ÇáÓáÇã) by converting old Arabic, Western and Asian encodings to UTF-8.
• Lines of code counter: Count code, comment and blank lines in your files.
• Chmod calculator: Unix file permissions: tick boxes to get 755-style numbers and rwx text, or the other way.
• IP address converter: Convert IPv4 between dotted, decimal, hex and binary, and expand or shorten IPv6.
• .gitignore generator: Build a .gitignore for Node, Python, Java, Android, Unity, macOS, VS Code and more.
• .htpasswd generator: Create .htpasswd lines with bcrypt for Apache and Nginx password protection.
• Content Security Policy generator: Build a Content-Security-Policy header by ticking sources, for HTML, Nginx and Apache.
• Regex library: Ready-made regular expressions for emails, links, phones, dates, colours and more, with a test box.
• Regex explainer: Explain any regular expression in plain English, piece by piece.
• Open source license generator: MIT, Apache 2.0, GPL 3.0, BSD, ISC and Unlicense texts with your name and year.
• Semver range checker: Check which versions match an npm range (^1.2.0, ~1.4, >=2) and sort versions.
• cURL to code converter: Turn a cURL command into JavaScript, Python, PHP, Go, Node and more.
• Docker run to Compose converter: Turn a docker run command into a docker-compose.yml file.
• JSON to classes (Java, C#, Python, Go, Kotlin, Swift): Generate classes and models in your language from a sample JSON.
• HTML to Markdown converter: Convert HTML to clean Markdown, with tables, code blocks and links kept.
• HTML to JSX converter: Turn HTML into React JSX: class to className, style objects and self-closing tags.
• SVG to React component: Turn an SVG into a React component with props, ready to paste.
• HTML, CSS and JS playground: Write HTML, CSS and JavaScript and see the result live, then download or share it.
• Mermaid diagram editor: Flowcharts, sequence diagrams, Gantt charts and more from text, as SVG or PNG.
• README generator: Build a good README.md with badges, install steps and sections, with a preview.
• Badge (shields) generator: Custom badges for your README or site, with your text, colours and icons, as SVG.
• Responsive image srcset generator: Write srcset and sizes markup for responsive images, and make the resized files.
• Nginx config generator: A server block for static sites, PHP, reverse proxy, HTTPS and redirects.
• .env converter: Convert .env files to JSON, YAML, Docker and shell exports, and back.
• File type checker: Find a file's real type from its first bytes, even when the extension is wrong.
• TOTP code generator: Make two-factor (authenticator) codes from a secret key in your browser, for testing.
• Git command builder: Pick what you want to do and get the exact git command, with a plain-English explanation.
• Webhook tester (mock request endpoint): A temporary address that records every request sent to it: method, headers and body.
• CSR (certificate signing request) decoder: Read a CSR or certificate: subject, key size, signature, SANs and validity, with warnings.
• OpenSSL command line generator: Build OpenSSL commands for keys, CSRs, self-signed certificates, conversions and checks.
• Dockerfile generator for modern languages: A good Dockerfile and .dockerignore for Node, Python, Java, Go, PHP, .NET, Rust, Ruby or a static site.
• Argon2 password hash generator: Hash and verify passwords with Argon2id, Argon2i or Argon2d, with recommended settings.
• Podcast RSS feed XML validator: Check a podcast feed against the RSS 2.0 and Apple Podcasts requirements.
• Cookie consent banner script generator: A cookie banner with accept, reject and choices, script blocking and Google Consent Mode v2.
• Google Maps location share and embed code maker: Embed code, share link and directions link for any address or coordinates.
• PX to REM converter: Convert px, rem, em and pt for any root font size.
• CSS box shadow generator: Design box shadows with sliders and a live preview, then copy the CSS.
• CSS border radius generator: Round each corner with sliders and copy the border-radius CSS.
• CSS flexbox generator: Play with flexbox settings on live boxes and copy the CSS.
• CSS grid generator: Build a grid layout with columns, rows and gaps, with a live preview.
• Cubic bezier generator: Drag a curve to design CSS easing, see it animate and copy the timing function.
• CSS clamp generator: Fluid font sizes that grow with the screen: get the clamp() formula.
• CSS specificity calculator: Work out which CSS selector wins, with each selector's (IDs, classes, elements) score.
• CSS clip-path generator: Drag points to make polygons, circles and shapes, then copy the clip-path CSS.
• CSS loader generator: Spinners and loading animations in pure CSS, with your colours and size.
• CSS button generator: Design buttons with gradients, shadows and hover effects, and copy the CSS.
• CSS text shadow generator: Glow, neon, 3D and long text shadows with a live preview.
• CSS animation generator: Bounce, fade, shake, slide and more as @keyframes, ready to copy.
• CSS filter generator: Blur, brightness, contrast and more on your own picture, with the CSS filter code.
• Text encryption and decryption: Lock a message with a password (AES-256) and unlock it again. Nothing leaves your device.
• File encryption: Encrypt any file with a password (AES-256-GCM) and decrypt it later, in your browser.
• Password leak checker: See whether a password appeared in known data breaches without sending it anywhere.
• Hash identifier: Find out which kind of hash (MD5, SHA-256, bcrypt…) a string is.
• IBAN validator: Check an IBAN's checksum and see its country, bank code and format.
• Credit card number validator: Check a card number's format and network with the Luhn test. No payment data is sent.
• IMEI checker: Check that a phone's IMEI number is valid and see what its digits mean.
• ISBN checker and converter: Validate an ISBN-10 or ISBN-13 and convert between them.
• Email address validator: Check an email's format and whether its domain can receive mail (MX records).
• SWIFT / BIC code decoder and validator: Check a SWIFT/BIC code and see its bank, country, location and branch parts.