# toolo

> Simple, fast developer tools that run in your browser: JSON formatter, Base64, JWT decoder, regex tester, cron generator, hash and password generators and more. No ads, no sign-up.

toolo.dev is a free set of single-purpose developer tools built by Abdul Basit Memon (https://abdulbasitmemon.com). Each tool has its own page, runs in the browser, and has no ads and no sign-up. The same tools are available to AI agents through an MCP server at https://toolo.dev/mcp (Streamable HTTP, no auth). Setup: https://toolo.dev/mcp-server.

## Encode & Decode

- [Base64 Encoder](https://toolo.dev/tools/base64-encode): Base64 encode text online. Text is read as UTF-8, so accents, Chinese and emoji match Node.js and Python, and a Base64URL switch makes JWT and URL-safe output.
- [Base64 Decoder](https://toolo.dev/tools/base64-decode): Base64 decode online to readable UTF-8 text. Accepts Base64URL, missing padding and data: URLs, and saves images, PDFs or ZIP files with the right extension.
- [URL Encoder](https://toolo.dev/tools/url-encode): URL encode text online to percent-encoding like %20 and %C3%A9. Encode one query value (encodeURIComponent) or a whole link (encodeURI), UTF-8 throughout.
- [URL Decoder](https://toolo.dev/tools/url-decode): URL decode online: turn %20, %3D and other percent-encoding back into UTF-8 text, and see every query parameter of a link decoded in its own table row.
- [JWT Decoder](https://toolo.dev/tools/jwt-decoder): JWT decoder: paste a token to read its header, payload and claims, see exp and iat as dates, and check if it has expired. Decoded in your browser, not uploaded.

## JSON & Data

- [JSON Formatter](https://toolo.dev/tools/json-formatter-validator): Format, validate and minify JSON online. See errors by line and column, browse a tree view, and keep big numbers and duplicate keys exactly as written.
- [JSON to YAML](https://toolo.dev/tools/json-to-yaml-converter): Convert JSON to YAML for Kubernetes, Docker Compose and GitHub Actions. Values like NO, 01234 and on are quoted, so the YAML keeps the meaning of your JSON.
- [YAML to JSON](https://toolo.dev/tools/yaml-to-json-converter): Convert YAML to JSON online: anchors, merge keys and multi-document files work, big integers stay exact, and errors show the line and column of the problem.
- [Sample JSON Generator](https://toolo.dev/tools/sample-json-generator): Generate sample JSON for API mocks and tests. Nest objects and arrays, start from a User, Product, Order or Blog post template, and get up to 1,000 records.
- [Fake Data Generator](https://toolo.dev/tools/fake-data-generator): Generate fake test data: names, emails, phone numbers, addresses, IBANs, UUIDs and more. Get up to 1,000 rows as JSON, CSV or a SQL INSERT statement.
- [Test Credit Card Generator](https://toolo.dev/tools/credit-card-number-generator): Get test credit card numbers for Visa, Mastercard, Amex, JCB, UnionPay and more, Luhn-valid with expiry and CVV, plus Stripe test cards and a validator.

## Text

- [Word Counter](https://toolo.dev/tools/word-character-counter): Count words and characters as you type, plus sentences, paragraphs, reading time and keyword density. Works for Chinese, Japanese and Thai text too.
- [Title Case Converter](https://toolo.dev/tools/title-case-converter): Convert text to title case for headlines, essays and YouTube titles. Short words like a, of and the stay lowercase, and each line becomes its own title.
- [Uppercase Converter](https://toolo.dev/tools/upper-case-converter): Convert text to uppercase (all caps) online, with accents and ß handled correctly. Also turns phrases into CONSTANT_CASE constants or PascalCase names.
- [Lowercase Converter](https://toolo.dev/tools/lower-case-converter): Convert uppercase text to lowercase online. Fix text typed with Caps Lock, clean up emails and tags, or switch to Sentence case, snake_case or kebab-case.
- [Lorem Ipsum Generator](https://toolo.dev/tools/lorem-ipsum-generator): Generate lorem ipsum placeholder text by paragraphs, sentences or words. Copy or download it as plain text, HTML paragraphs, an HTML list or JSON.
- [Markdown Preview](https://toolo.dev/tools/markdown-preview): Preview Markdown live as you type, with GitHub Flavored Markdown tables, task lists and footnotes. Copy the sanitized HTML or download your .md file.

## Security

- [Password Generator](https://toolo.dev/tools/random-password-generator): Generate strong random passwords from 4 to 128 characters. Choose letters, numbers and symbols, skip look-alike characters, and see the strength in bits.
- [Hash Generator](https://toolo.dev/tools/hash-generator): Generate a SHA-256 hash of text or a file, plus MD5, SHA-1, SHA-384, SHA-512 and HMAC. Paste a checksum or webhook signature to see which one matches.
- [AES Encrypt](https://toolo.dev/tools/encryptor): AES encryption online with AES-256-GCM: encrypt text under a passphrase and copy one Base64 string. No key or IV to manage, and the text stays in your browser.
- [AES Decrypt](https://toolo.dev/tools/decryptor): AES decryption online: paste text from the toolo AES encryptor, enter the passphrase and read it. Clear error messages, plus OpenSSL and Node.js decrypt code.

## Code

- [Regex Tester](https://toolo.dev/tools/regex-tester): Test regex online with live match highlighting, capture and named groups, and a find-and-replace preview. Uses JavaScript's RegExp engine with all eight flags.
- [JavaScript Minifier](https://toolo.dev/tools/javascript-minifier): Minify JavaScript online with Terser: short local names, dead code removed, strings and regex untouched. Or format minified JS to read it. Shows bytes saved.
- [CSS Minifier](https://toolo.dev/tools/css-minifier): Minify CSS online without breaking it: url(), strings, calc() and media queries stay valid. Keeps license comments, shows bytes saved, formats minified CSS.
- [HTML Minifier](https://toolo.dev/tools/html-minifier): Minify HTML online without breaking the layout: pre, textarea, script and style are left intact and word spacing is kept. Optional inline CSS and JS minify.
- [CSS Gradient Generator](https://toolo.dev/tools/css-gradient-generator): Make a CSS gradient with a live preview: linear, radial or conic, up to 10 color stops, transparency and presets. Copy the background CSS or a Tailwind class.

## Time & IDs

- [Cron Expression Generator](https://toolo.dev/tools/cron-expression-generator): Generate a cron expression field by field, or paste one to read it in plain English with the next 5 run times in any time zone. For crontab, Kubernetes and CI.
- [Unix Timestamp Converter](https://toolo.dev/tools/unix-timestamp-converter): Convert a Unix timestamp to a date in any time zone, or a date to epoch time. Reads seconds, milliseconds, microseconds and nanoseconds by their digit count.
- [UUID Generator](https://toolo.dev/tools/uuid-generator): Generate UUID v4 or time-ordered v7, up to 1,000 at once, with or without hyphens and braces. Paste any UUID to read its version and the time it was created.

## SEO

- [Meta Tag Generator](https://toolo.dev/tools/meta-tags-generator): Generate meta tags for SEO and link previews: title, description, canonical, robots, Open Graph and X cards. Preview it in Google and copy HTML or Next.js code.
- [SEO Content Checker](https://toolo.dev/tools/seo-content-checker): Check your content for SEO: title and meta description length, keyword density, headings, links, image alt text and sentence length. Paste HTML or a URL.

## Optional

- [Full text of every tool page](https://toolo.dev/llms-full.txt): how each tool works, examples and FAQ
- [MCP server setup](https://toolo.dev/mcp-server): connect Claude, Cursor, VS Code or any MCP client
- [About toolo](https://toolo.dev/about): who builds it and why
- [Privacy](https://toolo.dev/privacy): what is collected and what isn't