Put the address where the window is.
Live tool: windowfit.debother.com
WindowFit V0.2 is a focused, fully client-side A4 address-positioning and letter-composition utility for a supported German window-letter layout (DIN 5008 Type B window positioning). It runs entirely in your browser without accounts, backend servers, uploads, or tracking, and prints directly via the standard browser print dialog.
- Address positioning: Exact physical alignment for German standard window envelopes (DIN 5008 Form B).
- Sender line: Optional return-address or reference line in the separate upper address zone.
- Optional letter text: Draft or paste your letter text, place/date, and subject directly into the layout.
- Live A4 preview: Scaled, multi-page screen preview showing exactly where content and fold lines fall.
- Bilingual interface: Seamless switching between German (default) and English.
- Local-first privacy: Your address and letter data stay completely inside your browser.
The sole source of physical print dimensions is src/geometry.ts:
- A4 paper: 210 × 297 mm
- Complete address field: x = 20 mm, y = 45 mm, 85 × 45 mm
- Additional / sender zone: 85 × 17.7 mm (font size: 2.6 mm / 3.2 mm line height)
- Recipient zone: y = 62.7 mm, 85 × 27.3 mm, max. 6 lines
- Text inset: x = 25 mm (5 mm clearance from left field edge)
- Letter body top margin: y = 103.46 mm (below fold line 1)
- Calibration line: 100 mm
Automated tests cannot verify printer driver settings, browser scaling quirks, paper feed, or envelope fit.
- Print the built-in Test page at 100% / Actual size.
- Measure the printed calibration reference line with a physical ruler — it must measure exactly 100 mm.
- Disable browser headers and footers in the print dialog.
- Fold the sheet along the fold lines and verify that the address sits cleanly inside your physical envelope window.
npm install
npm run test
npm run lint
npm run buildFor local inspection: npm run preview -- --host 127.0.0.1.
MIT License. Copyright (c) 2026 Florian Hoffarth.
Made by debother.