Web Tools

Generate a .gitignore from 52 templates, with a panel showing exactly what git will do to a set of paths and which line decided each one, re-inclusions ordered so the order you pick the templates in cannot change the result, and any negation a parent directory blocks reported with its fix

Decode an X.509 certificate field by field, check which host names it covers, and verify that each certificate in a chain was signed by the one above it

Reusable checklists with nested items, templates and progress, kept in this browser, with a full store, a second tab and a document written by an older version all handled instead of losing them.

Pick a colour and read it back in ten notations, every one checked to parse back as the same colour. WCAG contrast ratios, the nearest CSS colour name, and colour vision simulation.

Build a cron expression and see its next runs in the zone the job will actually run in, with the day-of-month OR day-of-week rule and the daylight saving rules of crontab(5) applied

Build a Content Security Policy and see what a browser will actually apply, including the CSP3 rules that silently discard what you wrote.

Build a PKCS#10 certificate signing request with subject alternative names, RSA, ECDSA or Ed25519. Signed and verified in the page before you send it to a CA.

Build a CSS keyframe animation with the timing function held to what the specification allows: named, cubic-bezier and steps easings, a preview built from the same declarations as the copied CSS, and every problem the browser would refuse named before you paste it

Round corners in px or percent, circular or elliptical, and see the radius the browser will actually paint after the CSS overlap rule scales it down

Stack CSS box shadows with any colour notation, and never write a declaration the browser will drop: a layer that will not parse is left out and flagged rather than taking every other layer down with it

Design a CSS button and see every state measured against WCAG on the page colour you name: resting, hover, active, focus and disabled, plus the focus ring and the border.

Build a clip-path from polygons, circles, ellipses and rounded insets, with the fill rule exposed and the value checked before it is shown

Visual layout builder for CSS Flexbox and Grid where the generated CSS is the same declaration list the preview applies, checked to the pixel: twelve presets, the track list read against the CSS Grid grammar, and anything the browser will drop named

Build a CSS gradient and choose the colour space it is interpolated in, with the colour it keeps through the middle measured and shown.

Build a favicon from text, an emoji or an image and get a real favicon.ico holding 16, 32 and 48 pixel images, seven PNGs, a web app manifest and the head tags, in one archive, with the ICO parsed back from its own bytes before it is offered

25 curated Google Fonts pairings with the measurable parts measured: x-height and cap-height read off the loaded faces, weight menus offering only what each family publishes, and one link carrying exactly the weights the CSS uses

Frosted glass CSS where every setting can be set to zero, any colour notation works, and the reason backdrop-filter renders flat on a real page is written down

Encode and decode HTML character references against the full WHATWG table of 2,231 names, with the numeric remapping and the context rules a browser applies.

All 64 status codes the IANA registry has assigned, plus the 21 that nginx, Cloudflare, AWS and Laravel ship without one. Type any number and get an answer.

Build an invoice whose figures add up. Amounts on integers in the currency own ISO 4217 minor unit, fractional quantities, the discount taken before tax, and a PDF that gets written whatever alphabet the client name is in.

Write SEO, Open Graph and X card tags with every value escaped for an attribute, checked against the protocol, and the cut shown per platform.

Generate fake data that is the thing it is labelled: card numbers with a real Luhn check digit, IBANs that pass ISO 7064 MOD 97-10, UUID v4 and v7 per RFC 9562, reserved e-mail and IP ranges, a seed so the same data comes back, and JSON, NDJSON, CSV or SQL output

Paste a page head and see the card each platform actually gets: the title cut at its own limit, the image measured, and what the protocol says is missing.

Generate passwords from the Web Crypto generator by rejection sampling, with the entropy stated exactly from the alphabet, the cost of every rule computed, and crack times against four named attacker models

An upper bound on how strong a password is, from the patterns that actually make one guessable, with the model and its limits stated in full.

Convert certificates, requests, CRLs, keys and PKCS#7 bundles between PEM text and DER binary. The object type and the PEM label are read from the bytes, not asked for.

Work and break cycles on a monotonic clock, so a session is not ended by the system clock changing, with the running session and today figures kept if you reload.

Write a robots.txt by the RFC 9309 rules, then test a URL against it and see which rule wins and why.

Generate SSL/TLS certificates for local development, with hostnames placed in the Subject Alternative Name where browsers look. Exports PKCS#8, PKCS#1 and PKCS#12, with fingerprints and install config.

Build a Subresource Integrity attribute, with more than one hash if you want, and check an existing one against the file it is meant to pin.

Generate an SSH key pair in the OpenSSH format ssh-keygen writes: Ed25519, ECDSA or RSA, with the fingerprint and randomart it prints.

Read the certificate chain a server sends and say whether it is complete, in order and in date, and build the OpenSSL commands that fetch it.

Every fact about an IPv4 or IPv6 block, plus splitting, merging, range to CIDR, and which special-purpose range an address falls in

A stopwatch and a countdown on a monotonic clock, so neither loses time to a pause, a background tab or the system clock changing. Lap splits that add up, and a countdown that survives a reload.

Tasks with priorities, due dates and tags, kept in this browser, with a full store, a second tab and a document written by an older version all handled instead of losing the list.

Check a link for typosquats, brand-in-subdomain tricks, mixed-alphabet homographs, and hidden destinations. Public Suffix List parsing, explainable per-rule scoring, and the link is never fetched.

Read a user agent string and mark every field: read from a token, a frozen constant, or something the string cannot answer at all.

Your public IP address, checked against the IANA special-purpose registries so a private or shared address is named rather than called public, with the location shown as the estimate it is.

A knowledge base with double-bracket links, backlinks and tags, kept in this browser, with the storage limit shown and a refused save reported rather than losing the note.