Essential developer utilities — encode, hash, test, generate. All tools are 100% free, with no sign-up except the AI tools, and every one runs entirely in your browser — nothing is ever uploaded.
One editor, 38 operations — chained, with undo
Paste code once and keep working on it: format and validate JSON, YAML and SQL, convert between JSON, YAML, XML, CSV and TypeScript, encode, hash, and generate UUIDs, passwords or QR codes. Every step is undoable, and Compare shows exactly what each one did — including when a change was formatting only. Eight AI actions explain, debug, refactor and write tests, and every one of them opens in a review before it touches your file.
def fibonacci(n):
if n <= 1: return n
return fib(n-1) + fib(n-2)
# NameError: fib is not defined
Bug: rename fib → fibonacci
Prettify, minify, and validate JSON — with the exact parser error when it breaks.
Generate QR codes from URLs or text. Custom colors and size. Download PNG or SVG.
Generate strong random passwords. Custom rules, strength meter, batch mode.
Encode and decode text or files to Base64. Fast, free, in-browser.
Encode and decode URL components. Handle special characters for query strings.
Decode JWTs, run health checks, and verify HS256/384/512 signatures locally.
Prettify, minify, and validate JSON — with the exact parser error when it breaks.
Validate and pretty-print YAML — with error line numbers and key sorting.
Beautify minified JavaScript, CSS, HTML, and JSON with a live preview.
Format and beautify SQL for PostgreSQL, MySQL, T-SQL, and 7 more dialects.
Minify JavaScript, CSS, HTML, and JSON — with live byte savings.
Encode and decode text or files to Base64. Fast, free, in-browser.
Encode and decode URL components. Handle special characters for query strings.
Encode special HTML characters to entities and decode entities back to HTML.
Convert Unix timestamps to human-readable dates and back. Multi-timezone.
Convert numbers between binary, octal, decimal, hex, and any base 2–36.
Convert JSON to CSV and CSV back to JSON — with proper quoting and type coercion.
Generate TypeScript interfaces from a JSON sample — nested types included.
Convert JSON to YAML and YAML back to JSON — losslessly, both directions.
Convert JSON to XML and XML back to JSON — attributes preserved, both directions.
Generate strong random passwords. Custom rules, strength meter, batch mode.
Decode JWTs, run health checks, and verify HS256/384/512 signatures locally.
Generate MD5, SHA-1/256/512 & SHA-3 hashes — or keyed HMACs — from text or files.
Generate and verify bcrypt password hashes with an adjustable cost factor.
Build linear and radial CSS gradients visually. Copy CSS code with one click.
Pick any color and convert between HEX, RGB, HSL, and CMYK formats instantly.
Check colour contrast against WCAG AA/AAA, with a live text preview.
Design CSS box-shadows visually with a live preview and copy-paste output.
Round corners visually — link or independently — with live preview and CSS.
Design CSS easing curves with draggable handles and a live animation preview.
Test regular expressions live. See all matches highlighted in real time.
Explain a cron expression in plain English and preview its next run times.
Searchable reference of HTTP status codes with plain-English meanings.
Calculate Unix file permissions — octal, symbolic, and the chmod command.
Build a .gitignore from language, tool, and OS templates — combine any stacks.
Look up MIME types by file extension — or extensions by MIME type.
Built for speed, privacy, and quality — no bloated apps or subscriptions needed.
Generate QR codes with custom colors, sizes, and error correction.
Decode and inspect JWT tokens — header, payload, and signature.
Live regex matching with flags, match groups and a pattern cheat sheet.
MD5, SHA-1, SHA-256, SHA-512 and SHA-3 from text or files — plus keyed HMAC.
Encode/decode Base64 strings and files. Supports binary data.
Visual gradient builder with live preview and copy-ready CSS output.
Popular use cases
Everything you need to know about our developer tools.
Yes, for every developer utility — hashing, encoding, decoding, regex testing, JWT decoding, and QR code generation all run in your browser, and nothing is sent to a server. The exception is Dev Studio's 8 AI actions, which send the code you give them to an AI provider to produce an answer; the studio's other 30 operations work like the standalone tools.
Yes — QR codes you generate are yours to use for any purpose including commercial use. There are no watermarks. Download a PNG, or an SVG that stays sharp at any print size.
Yes. Decoding runs entirely in your browser and your tokens are never sent to any server. It can also verify HS256/384/512 signatures locally when you paste the shared secret; tokens signed with a private key (RS or ES algorithms) still need your backend to verify.
No. Generated passwords exist only in your browser's memory and are never transmitted anywhere. Close the tab and they're gone. For best security, copy the password immediately and store it in your password manager.
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Read guideDeveloper Reference Tools: Chmod, HTTP Codes, MIME & More
Convert chmod permissions, look up HTTP status codes and MIME types, make a .gitignore or bcrypt hash, and check WCAG contrast — free, in your browser.
Read guideCSS Generators & Code Formatters: The Developer Toolkit
Build CSS box-shadows, border-radius and easing curves visually, then tidy messy code and convert between JSON, YAML and XML — free, in your browser.
Read guide34 tools, completely free. Only the 1 AI tool asks you to sign in. Start with our most popular tool.