Fundamentals guides

Pretty-print, validate and squish JSON. No server involved.

Tame ugly XML and poke around its tree structure.

Crack open a JWT and peek at its header, payload and expiry.

Check your YAML's indentation sins and flip it to/from JSON.

Type Markdown, watch it render live — zero XSS surprises.

Untangle messy SQL into something your eyes can parse.

Paste raw HTTP and get a readable, field-by-field breakdown.

Drop in HTML and watch it render right beside the source.

Base64 in, Base64 out, with a live preview — no guesswork.

URL-encode or decode whole links or just the fiddly bits.

Crank out MD5 and SHA hashes without pinging a server.

Turn messy CSV into a table, or flip it to and from JSON.

Decode cron syntax into plain English and the next run times.

Flip Unix timestamps to dates and back, plus a live clock.

Convert px, rem, em, vw and friends, and build fluid clamp() values.

Throw your regex at real text and see what matches (and what doesn't).

Diff two files side by side and see exactly what changed.

Merge two file versions side by side — pick a side per change, done.

Turn a cURL command into fetch, Axios, Python, Go or PHP code.

Build raw HTTP requests or responses, headers, body and files included.

Crunch an IPv4 CIDR into network, broadcast, hosts and masks.

Make GraphQL queries and schemas readable (or squish them down).

Clean, shrink and preview SVGs, then export as Data URI or Base64.

Turn one image into every favicon size plus the head tags.

Flip images to Base64/Data URI and back, with resize and compression.

Convert JPG/PNG/GIF to WebP (or back), resize, compress, download.

Lock and unlock text with password-based AES encryption.

Scan your CSP header for sketchy directives and gaps.

Get a report card on your security headers, plus fixes.

See how fast a password would crack, patterns and all.

Generate SRI hashes and the script/link tags that use them.

Sign payloads with HMAC and double-check webhook signatures.

Tidy up or shrink your JS/TS — your pick, your style.

Fix busted indentation across JS, TS, JSON, HTML, CSS, YAML and more.

Edit JSON as text, tree, table or form — side by side, then download.

Edit XML as text, tree, table or form — side by side, then download.

Edit YAML as text, tree, table or form — side by side, then download.

Write Markdown and rich text side by side — toolbar included, always in sync.

Edit HTML with a live preview, auto-formatting and a one-click download.

Spit out one or a thousand UUIDs, formatted your way.

Generate random numbers or strings with your own charset.

Fill the void with as much Lorem Ipsum as you need.

Cook up strong passwords with length and charset to taste.

Make QR codes from any text or link, with color and size options.

Generate Code 128, EAN-13, UPC and more barcodes, ready to download.

Spin up realistic fake JSON records for your tests, field by field.

Pick a color and juggle it between HEX, RGB, HSL, OKLCH and more.

Turn one brand color into a full site palette, then preview it live.

Check WCAG contrast and get an instant fix if it fails.

Spin up random colors that actually look distinct from each other.

Build a Tailwind-style 50-950 scale from any color, export-ready.

Open Excel sheets and export them as CSV, JSON, HTML or Markdown.

Turn JSON arrays into a real .xlsx file, nested fields flattened.