31 simple tools for everyday developer work: format JSON, decode a JWT, encode Base64, test a regex, build a cron expression, generate a password. Free, fast, and private.
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 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 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 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: 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.
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.
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.
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.
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.
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.
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.
Count words and characters as you type, plus sentences, paragraphs, reading time and keyword density. Works for Chinese, Japanese and Thai text too.
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.
Convert text to uppercase (all caps) online, with accents and ß handled correctly. Also turns phrases into CONSTANT_CASE constants or PascalCase names.
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.
Generate lorem ipsum placeholder text by paragraphs, sentences or words. Copy or download it as plain text, HTML paragraphs, an HTML list or JSON.
Preview Markdown live as you type, with GitHub Flavored Markdown tables, task lists and footnotes. Copy the sanitized HTML or download your .md file.
Generate strong random passwords from 4 to 128 characters. Choose letters, numbers and symbols, skip look-alike characters, and see the strength in bits.
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 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 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.
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.
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.
Minify CSS online without breaking it: url(), strings, calc() and media queries stay valid. Keeps license comments, shows bytes saved, formats minified CSS.
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.
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.
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.
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.
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.
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.
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.
Each tool is one simple page. No ads, no pop-ups, no sign-up, no cookie wall.
Tools run in your browser. Tokens, passwords and JSON are not sent to a server.
Connect the toolo MCP server to Claude, Cursor or VS Code and let your agent use the same tools. Set it up
