💻 Developer Toolkit — Free Online Dev Tools
Format JSON, decode JWTs, hash, Base64, UUIDs, CSV↔JSON and more — runs locally, so your tokens and data never leave the browser.
Tools in this kit
{ }JSON Formatter & BeautifierJSON pretty-print, beautifier, minifier, and validator — all in your browserImage to Base64Turn an image into a Base64 data URI, or encode and decode Base64 text — and turn Base64 back into a file#️⃣Hash GeneratorGenerate cryptographic hashes from text or files🔑JWT DecoderDecode JSON Web Tokens — see header, payload, and expiration🆔UUID GeneratorGenerate universally unique identifiers — offline and secure📊CSV ↔ JSONConvert CSV to JSON or JSON to CSV with custom delimiters⚙️YAML ↔ JSONConvert YAML to JSON or JSON to YAML with validation🔗URL Encoder / DecoderEncode or decode URLs and query strings instantly🕐Timestamp ConverterConvert between Unix timestamps and human-readable dates🔍Regex TesterTest and debug regular expressions with real-time matching🎨Color ConverterConvert colors between HEX, RGB, HSL, CMYK, and HSV formats📝Markdown ↔ HTMLConvert Markdown to HTML or HTML to Markdown with live preview📊JSON to CSV / Excel ConverterPaste a JSON array of objects and download it as CSV or an Excel (.xlsx) file — handles nested keys, quoting and custom delimiters. 100% in your browser.⭐Favicon GeneratorGenerate ICO + PNG favicons in all sizes from a single image
Related how-to guides
- 📖 How to Create a Favicon From an Image (ICO + PNG, All Sizes) — Turn any image into a favicon for free — get a favicon.ico plus PNGs at every size (16 to 512), copy the HTML tags, and ship it. All in your browser, no upload.
- 📖 How to Convert JSON to CSV or Excel — Turn a JSON array of objects into a CSV or a real .xlsx Excel file, right in your browser. How the columns are built, what to do about nested data, and why it stays private.
- 📖 How to Encode and Decode Base64 (and Turn an Image Into a Data URI) — Encode and decode Base64 text, and convert a small image into a data URI you can inline in CSS or HTML — all locally in your browser, nothing uploaded.
- 📖 How to Convert CSV to JSON (and Back) — Convert CSV to JSON in your browser — an array of objects keyed by the header row — and back again. Plus the gotchas with quoting, delimiters, and type coercion.
- 📖 How to Decode a JWT (Safely — Without Leaking It) — Decode a JWT to read its header and payload in seconds — and why pasting a live token into a random online decoder can get your session hijacked.
- 📖 How to Format, Validate, and Beautify JSON — Pretty-print messy JSON, catch syntax errors with line numbers, and minify for production — all in your browser without uploading API responses full of tokens.
- 📖 How to Generate an MD5 or SHA-256 Hash (and Verify a Download) — Generate MD5, SHA-1, or SHA-256 hashes in your browser and verify a downloaded file matches the publisher's checksum. Plus an honest note on which are broken.
- 📖 How to Generate a UUID (v4) — and When You Actually Need One — Generate one or many random UUID v4 / GUID values in your browser. Learn when to use a UUID as a key and when you should NOT use one as a security token.