Patens

A type design tool that teaches as you draw. Sketch glyphs with a pencil, trace to Bézier, ship OpenType — and learn from a 94-code audit module with plain-English fixes for everything from spacing to OpenType invariants.

patens.design · Latin: lying open — root of patent, before lawyers got there.

Patens is a browser-native, open-source SvelteKit app for designing type. Every project lives in the browser's IndexedDB; nothing leaves your machine unless you choose to export. The differentiator isn't that it's browser-native — it's that the audit module is a citizen of the editor, not an afterthought. Every glyph, every metric, every kern pair has a teaching surface: "your sidebearings drift across the stem class" or "this contour winds the wrong way for OpenType" — with the rule, the why, and a one-click fix where one exists. (Why audit-as-teaching →)

The demo project ships 162 drawn glyphs across Latin (uppercase + lowercase, numerals, punctuation, currency, math, brackets, composite ligatures), a partial Cyrillic set (17 look-alike letters reusing Latin builders + bespoke Я Ж Ф), and a partial Greek set (14 uppercase look-alikes) — enough to set a UI, a price table, or a Bulgarian legal footer without falling back to system fonts.

Try it

• Live editor: patens.design/project/demo/edit
• Demo specimen: patens.design/share/demo

The share view is a designer-grade specimen sheet: pangram waterfall at five sizes, reading specimens at three tiers, in-context mockups (button, headline, paragraph, stat), CPAL palette switcher, master compare, glyph coverage heatmap, glyph inspector with metric guides + sidebearings + anchor viz, deep-linkable glyph URLs, and a one-click print → PDF specimen.

What it does

Project status

v1.5.2 — production-grade. Live at patens.design. Three optional integrations gracefully degrade when not configured:

• Vercel Blob — cloud share (recipients in other browsers)
• GitHub OAuth — sign-in via GitHub
• Anthropic API key — AI presets (audit explanations, consistency, kerning suggestions; user-provided key, no shared cost surface)

Setup per host (Vercel, Cloudflare Pages, Netlify, self-host): see docs/setup.md.

For what's deferred: ROADMAP.md. For release history: CHANGELOG.md (also at patens.design/changelog · RSS).

Running locally

pnpm install
pnpm dev          # http://localhost:5173

pnpm test         # vitest (528 unit tests + 6 perf benches)
pnpm test:e2e     # Playwright + axe-core a11y (66 e2e tests across 7 files)
pnpm check        # svelte-check / TypeScript strict
pnpm build        # production build
pnpm profile      # cold-load CDP trace (any URL)

CLI — patens audit from the terminal

Audit a .font.json project without opening the editor — useful for CI, foundries lint-checking client deliverables, or scripted batch work. The CLI is a thin shell around the same 94-code audit module the editor uses, packaged for Node 22+.

pnpm run cli:build           # bundles cli/dist/index.mjs (one-time)
pnpm patens audit my.font.json
pnpm patens audit my.font.json --severity=error  # CI-friendly
pnpm patens audit my.font.json --json | jq '.'   # machine output
pnpm patens audit my.font.json --github          # PR annotations
pnpm patens describe self-intersecting           # explain a code
pnpm patens help

Exit code is 0 when no error-severity issues, 1 when there are, 2 on usage / parse failure. Drop-in CI:

- run: pnpm run cli:build
- run: pnpm patens audit fonts/*.font.json --github --severity=warn

Architecture (one paragraph)

Every project is a single JSON blob (typed as Project in src/lib/font/types.ts) stored under a UUID key in IndexedDB via idb-keyval. The editor reads through a projectStore reactive store; mutations re-emit + auto-save. The share page is ssr=false and loads from the local IndexedDB — its only network dependency is the static SvelteKit build itself. Export is dual-path: OTF/WOFF2 via opentype.js in the browser, TTF + ttfautohint via Pyodide running as WASM. The audit module is the spine: 94 codes feeding five teaching surfaces (edit panel, audit page, release pre-flight, family hub, home page) through a single describeAuditCode() dictionary. Cloud share uses Vercel Blob with token-based auth (constantTimeEqual for token comparison); sign-in uses HMAC-signed session cookies (safeReturnTo against open-redirect). Full setup details in ARCHITECTURE.md.

Contributing

See CONTRIBUTING.md. PRs welcome. Run pnpm check && pnpm test && pnpm test:e2e before submitting.

For security issues: see SECURITY.md or email [email protected].

License

MIT. The demo project's glyph data is part of the codebase under the same license; export an OTF and use it however you'd license your own work.

Made by Alejandro Vizio — @patenstype on X, @patens.design on Bluesky, [email protected] for everything else.