All free developer tools
Every free developer tool on DoAide Code in one place: 35 tools — AI code review, explainers and converters, plus formatters, a regex tester, SQL and JSON validators, snippet sharing and more. No sign-up. Each tool lives at its own URL, works in the browser, and is free without an account.
AI code tools
Paste code, get an answer: these tools run your code past an AI model on the server and stream the result back.
Explain Code
Paste code in any language and get a plain-English, step-by-step explanation. Free, no sign-up.
AI Code Review
Get a senior-engineer review of your code: correctness, security, performance and readability, with fixes. Free, no sign-up. Read the guide.
Find Bugs in Code
Paste a function and find the bugs: what breaks, the input that triggers it, and the fix. Free, no sign-up.
Add Comments to Code
Paste code and get it back with clear comments that explain what it does and why. Free, no sign-up.
Convert Code
Translate code from one programming language to another: Python to JavaScript, Java to Kotlin, and more. Free, no sign-up. Read the guide.
Optimize Code
Paste code and get a faster version back, with each change explained: better algorithms first, micro-tweaks last. Free, no sign-up.
Code Documentation Generator
Paste code and get it back with idiomatic documentation comments: JSDoc, Python docstrings, Javadoc or godoc, with parameters, return values and examples. Free, no sign-up. Read the guide.
Generate Unit Tests
Paste a function and get runnable unit tests: happy path, edge cases and error handling, in the idiomatic framework. Free, no sign-up. Read the guide.
Developer utilities
Instant, in-browser utilities: everything below is computed in the page, so your code and data never leave your machine.
Code Diff Checker
Paste two versions of a file and see every added, removed and changed line side by side. Free online diff checker, no sign-up.
Code Formatter
Beautify JavaScript, JSON, CSS, HTML or Python: consistent indentation, right in your browser. Free, no sign-up. Read the guide.
Regex Tester
Type a regex and a test string and see every match and capture group highlighted as you type. Free, no sign-up. Read the guide.
Embeddable Code Widget
Paste code and get an iframe snippet for your blog, docs or README site. Readers see the snippet and open it in the free AI tools with one click. Free, no sign-up. Read the guide.
Share Code Snippets
Paste code and get a short link anyone can open: syntax highlighted, up to 20,000 characters, no sign-up. Share snippets on WhatsApp, Slack or anywhere. Read the guide.
Code Playground
Type code and run it instantly in a sandboxed frame: JavaScript natively, Python on WebAssembly. Nothing is uploaded. Free, no sign-up.
SQL Formatter & Validator
Paste a SQL query to format it — one clause per line, keywords uppercased — and catch unbalanced parentheses, unterminated strings and missing WHERE clauses. Free, no sign-up. Read the guide.
Code Templates Library
Pre-built templates for the patterns you write over and over: React components and hooks, Express and FastAPI endpoints, Python classes and CLIs, SQL CRUD, Go servers. Copy and go. Free, no sign-up.
Code Complexity Analyzer
Paste code and get cyclomatic complexity per function, lines of code, comment ratio and nesting depth — with the functions worth refactoring flagged first. Free, no sign-up.
Markdown Editor & Preview
Type Markdown and see it rendered side by side: headings, lists, links and syntax-highlighted code blocks. Copy the HTML or download the .md file. Free, no sign-up.
JWT Decoder
Paste a JWT to see the decoded header and payload, every registered claim explained, and whether the token is expired. Runs in your browser — the token is never uploaded or stored. Free, no sign-up.
Cron Expression Builder
Type or pick a cron expression and read it back in plain words, with the next five run times in your timezone. Lists, ranges, steps and @daily shortcuts all work. Free, no sign-up.
Base64 Encoder & Decoder
Encode text to Base64 or decode it back as you type — UTF-8 safe, URL-safe variant included, forgiving of missing padding. Runs in your browser, nothing is uploaded. Free, no sign-up.
CSS Gradient Generator
Pick colors and positions, see the gradient live, and copy the CSS — linear, radial or conic, up to six stops, with ready-made presets. Free, no sign-up.
Developer Unit Converter
px to rem/em at any root font size, bytes in decimal and binary, unix timestamps to dates, and colors between hex, rgb and hsl — all as you type. Free, no sign-up.
Code Screenshot Generator
Paste a snippet and download a polished PNG — gradient backdrop, editor window chrome, syntax colors, five themes. Rendered in your browser, nothing is uploaded. Free, no sign-up.
SHA Hash Generator
Type text and get its SHA-1, SHA-256, SHA-384 and SHA-512 hex digests live, computed with WebCrypto in your browser — nothing is uploaded. Free, no sign-up.
URL Encoder & Decoder
Percent-encode text for URLs or decode it back as you type — component mode for query values, whole-URL mode that keeps structure, + read as space. Free, no sign-up.
Unix Timestamp Converter
Paste unix seconds, milliseconds, ISO 8601 or RFC 2822 and get every format back, plus the moment in any timezone — as you type, in your browser. Free, no sign-up.
Lorem Ipsum Generator
Filler text by the word, sentence or paragraph in three styles — classic Latin, tech filler, plain English — copied as text or HTML paragraphs. Free, no sign-up.
String Utilities
camelCase, snake_case, kebab-case and five more conversions, URL slugs, reversed text, and character/word/line/byte counts — all live as you type. Free, no sign-up.
JSON Path Finder
Paste JSON, click any value in the tree, and copy its JSONPath expression or JavaScript accessor — quoting awkward keys for you. Free, no sign-up.
HTML Preview
Type HTML, CSS and JavaScript in three panes and watch the result render live in a sandboxed preview — runtime errors shown inline. Free, no sign-up.
Markdown to HTML Converter
Paste Markdown and get clean HTML with a live preview — headings, lists, tables, fenced code and links, with raw HTML safely escaped. Free, no sign-up.
Image to Base64 Converter
Drop an image and copy it as a Base64 data URL, raw Base64, an <img> tag, CSS background or Markdown. Converted in your browser, never uploaded. Free, no sign-up.
QR Code Generator
Type text or a URL and download the QR code as a crisp SVG or PNG, with selectable error correction. Generated in your browser, nothing uploaded. Free, no sign-up.
JSON Formatter & Validator
Paste JSON to validate it, see the exact line of any error, and explore it as a collapsible tree. Free, no sign-up.
Learn the workflows
The guides cover the workflows behind these tools — AI code review, formatting, regex building, SQL hygiene and snippet sharing — with the tool for each step linked in place.
Open the free tools