Lekh Patro (लेख) — Nepali Typing, Translation, Calendar & Tools

Type Nepali without a Nepali keyboard: write romanized Nepali — kasto chha — and Lekh Patro converts it to Devanagari — कस्तो छ — as you type, IME-style, right in the browser.

Live (install from there): https://lekh-gamma.vercel.app

What it does

Four tabs — Type, Translate, Patro and Tools:

• Type — a phonetic transliteration engine backed by an 887-entry dictionary shows suggestion chips (with spelling variants) as you type. The dictionary knows the English words people mix in (school → स्कुल, facebook → फेसबुक) and the way people actually text (tapaailai → तपाईंलाई, vayo → भयो). A searchable Devanagari cheat sheet covers the long tail, and tapping a cell echoes the result inside the sheet so you can see the letter land without closing it. Works with mobile keyboards/IMEs (Gboard-style commit flow).
• Translate — English ↔ Nepali with a Google-style language switcher. Type directly or drop in a photo, PDF, DOCX, or TXT file — OCR happens entirely in the browser via Tesseract.js, and nothing is uploaded to any server. Online translation by default, plus an optional fully on-device NLLB-200 model (Transformers.js) — private and offline-capable once cached (large download, fetched in phases with progress). Every Nepali translation carries a plain-Latin pronunciation line under it (कृपया मलाई ठमेल लैजानुहोस् → Kripaya malai thamel laijanuhos), and Show holds it up full-screen in large type for a taxi driver or shopkeeper.
• Patro — a Bikram Sambat calendar with festivals, public holidays and tithi. About 70 festivals and national days also have an English name, a line on what happens and, where it matters, a note for visitors ("offices, banks and many shops close from Fulpati until after Tika") — written by hand, see below. No ads, no account.
• Tools — five small tools behind one switcher, so the tab shows the one you picked rather than a long scroll of all of them: a BS ↔ AD date converter; numbers in words for a cheque or a price you can't read (१२,५००.५० → बाह्र हजार पाँच सय रुपैयाँ पचास पैसा मात्र, in Nepali and English, lakh/crore grouping); a currency converter at Nepal Rastra Bank's daily rates for the 22 currencies it quotes (the buying rate into rupees, the selling rate out of them, and the last rates kept for offline use); Preeti ↔ Unicode, which also notices romanized Nepali pasted into it; and an offline phrasebook for travellers — 43 phrases in five topics, searchable, each with its pronunciation and a full-screen Show, under the emergency numbers (Police 100, Tourist Police 1144, Ambulance 102, Fire 101) as tap-to-dial links.

How the romanization maps

Lekh types the way ashesh.com.np's romanized Nepali Unicode converter does — the pattern most Nepali typists already know — so the same keystrokes give the same letters. Common words come from Lekh's own dictionary first (reviewed by a native speaker), the way ashesh keeps one too; everything else follows the pattern.

• Case: only T, D, N and Sh are case-sensitive — त/ट, द/ड, न/ण, श/ष. Every other capital is its lowercase letter, so Anil → अनिल.
• Vowels: a consonant carries its a (ka → क); aa ा, i ि, ee ी, u ु, oo ू, e े, ai ै, o ो, au ौ. ri after a letter is ृ (kri → कृ); ri^ gives the र-cluster instead (kri^ket → क्रिकेट).
• Consonants: aspirates are digraphs (kh gh chh jh th dh ph bh, Th Dh), ksh क्ष, gy ज्ञ, yna ञ — so ny is a plain न्य — and c क, x क्स.
• Signs: * ं and ** ँ (Lekh's older M and ~ still work), H ः. Clusters join on their own; \ writes a halant where one would not appear (bas\ → बस्), and / keeps two letters apart.
• Word endings, as on ashesh: a final -i after a consonant is ी (nepaali → नेपाली), and a final -cha is छ (garcha → गर्छ). One deliberate difference: a final y is ी (story → स्तोरी), where ashesh's rule runs into its own rree key and gives स्तोॠ.

src/lib/engine/maps.ts is the table, convert.ts the word rules, and src/lib/engine/engine.test.ts pins each of the above.

Design

Crimson & Paper — the Nepali flag's colours, by role rather than by decoration. Crimson is the only accent and it always means "you can press this"; the flag's deep blue is folded into the neutral ramp, so every dark surface is a blue-black rather than a neutral grey, and appears literally only in the wordmark. Every foreground/background pair in both themes is computed from WCAG relative luminance and recorded in src/index.css — the tightest is 4.62:1, and borders come in two strengths because a decorative hairline and a control you must be able to find have different floors.

Material You — on Android 12 and up, the app in the Play/APK build wears the palette Android derives from the user's wallpaper instead, and so do the home-screen widgets. Only the colours change: layout, spacing, shape, type and motion are the same design underneath. Crimson & Paper stays the app's identity on the web, in the PWA, on Android 11 and below, and for anyone who turns wallpaper colours off in Settings.

It is not a lookup table. Android's shade numbers are only guaranteed to mean a given lightness on a phone running something close to AOSP — several OEMs substitute their own palette extraction — so src/lib/dynamicColor.ts walks a candidate list per role and measures each one, holding the wallpaper's colours to the same floors src/index.css records for the hand-picked ones.

The chrome is one strip: brand, section nav and actions in a single app bar on a wide screen, with the same nav detaching to a bottom dock on a phone. The editor is the whole Type page — the cheat sheet is a searchable panel behind one button rather than a permanently-expanded wall of 73 cells.

The first launch of a session opens on a boot screen instead of a landing page, so the app announces itself once and then gets out of the way — later launches in the same session go straight to the editor.

The calendar, and why its festivals run out

Dates and festivals are two different problems, and only one of them is solvable in general.

Dates are computable. BS months run 29–32 days on a pattern set by solar transits rather than a formula, so every implementation ships a lookup table; nepali-date-converter (MIT) has one for BS 2000–2090. The grid and the converter work across that whole span.

Festivals are not. Dashain, Tihar, Teej, Shivaratri, Janai Purnima and most of the rest fall on a tithi — a lunar day — which needs real lunar ephemeris plus the panchang convention about which sunrise a tithi counts against. Doing that in the browser would be a large bundle and a good chance of landing one day out, and a Dashain on the wrong day is worse than no Dashain at all. So they are tabulated by npm run calendar:data, and the table has a hard end. The UI states the covered range rather than rendering an uncovered month as one that simply has no festivals in it.

Holidays refresh over the network. The bundled table is the offline baseline and renders instantly; the app then fetches the same month from upstream, which re-scrapes daily, so a holiday added or dropped by cabinet decision arrives within about a day and years past the bundled range work without a redeploy. The calendar says which source the month on screen came from — this is the calendar's only network call, and it is not hidden. It is a plain GET for a public file with nothing about you attached, and the service worker caches it so a month fetched once keeps working offline.

Two guards apply to live data, because nothing fetched at runtime has been reviewed. A month whose length disagrees with the conversion table is rejected, and so is a month with no festival names at all — that is what an unpublished year looks like (BS 2084 currently returns 31 days and zero festivals despite Baisakh 1 being नयाँ वर्ष), and rendering it would claim the month has no festivals. Across the 36 bundled months the count runs 11–25 and is never 0, so zero is a safe signal rather than a guess.

That generator cross-checks every month length against the conversion table and drops any year where the two sources disagree. This is not paranoia: BS 2084 currently disagrees on five of twelve months, and shipping it would have put every festival from Jestha onward on the wrong square while looking entirely normal.

Festival data comes from S4NKALP/nepali-calendar-api (MIT, © 2026 Sankalp Tharu), which scrapes nepalicalendar.rat32.com — a third-party almanac, not an official Government of Nepal notice. Public holidays are set by cabinet decision and do move.

English names are hand-written, and deliberately incomplete. src/lib/calendar/festivalsEn.ts covers about 70 festivals and national days — every named Dashain and Tihar day, the Kathmandu Valley jatras, the Lhosars, the national days — with names in common English use and who gets the day off taken from the Ministry of Home Affairs' public-holiday notice for BS 2083, and what happens from the Nepal Tourism Board and standard references. Everything else stays in Nepali only, in Patro and in the widget's English mode alike. The widget once had English for every name, generated or scraped, and too many came out wrong ("Naaga", "Panchamee"); a missing line is better than a wrong one. The almanac has no entry called Laxmi Puja or Mha Puja — those days are गाई पूजा and गोरू पूजा — so that is where their English lives.

A Saturday festival is only a public holiday if it is one in its own right. The almanac flags nearly every Saturday, so its flag alone would list a weekly vrat beside Constitution Day. On a weekly off, a day counts only when one of its festivals has been a declared holiday on a weekday somewhere in the bundled years.

Nepal now has a two-day weekend. Saturday has always been the weekly day off; the cabinet added Sunday on 5 April 2026, effective the next day — Chaitra 23, 2082 = 6 April 2026. The rule is dated, not global, so paging back to BS 2081 still shows a one-day weekend rather than rewriting history. It covers government offices and educational institutions; several local levels rejected it and the private sector is not covered. If it is ever reversed, add an end date to TWO_DAY_WEEKEND_FROM rather than deleting it.

The weekly pattern is applied as a rule and deliberately not taken from the festival data, whose own holiday flag is inconsistent about weekends — 29 of 53 Saturdays in BS 2081 against 48 of 52 in BS 2082 — and does not encode the Sunday policy at all.

One rule for anyone touching this code: never read these dates back with toISOString(). The converter returns a Date at local midnight, and Nepal is UTC+05:45, so a UTC read moves every festival a day earlier. That mistake was made once already while verifying this feature and looked exactly like a data error.

Android home-screen widget

android/ holds a small native Kotlin widget showing today's BS date, tithi and festival. It exists because a PWA cannot provide an Android home-screen widget — the widgets manifest member is Microsoft's Windows 11 Widgets Board feature, not the Android home screen, so a native AppWidgetProvider is the only route.

It shares the web app's calendar data rather than duplicating it (npm run android:assets), and its date algorithm was validated against nepali-date-converter over 3,970 conversions. It ships in four sizes — 2x1, 2x2, 4x1 and 5x1 — each built around a small calendar leaf, a crimson strip carrying the weekday over the date, taken from the logo's शिरोरेखा. It draws in Nepali by default and in English if you choose it in Settings → Home-screen widget. The English mode uses only the hand-checked festival names above (exported to the widget by npm run android:assets); a festival without one is not named in English and the widget shows the tithi instead. An earlier English mode transliterated every name and was removed for getting too many wrong. The 5-wide grows a week strip when you make it taller, which is what replaced the separate 4x2 and 5x2 sizes. It ships as part of the Capacitor Android app that wraps the web app (capacitor.config.ts's server.url points at the live site, so most web fixes ship without a new build), and is on Google Play since 2026-10-02. See android/README.md for the build and widget details.

Installing and updating

Which one you want:

You are on	Install	Why
Android	Google Play, or the .apk on a phone without Play	Home-screen widgets. A PWA cannot provide them — the widgets manifest member is Microsoft's Windows 11 feature, not the Android home screen — so the Android build is a real app, not an installed web page.
iPhone / iPad	the PWA — Share → Add to Home Screen	There is no Android-style install prompt on iOS, and no App Store build.
Desktop	the PWA — install button in the header	Works in any Chromium browser.

Everything else is identical between them: same typing engine, same OCR, same calendar, same offline behaviour. The Android app is a Capacitor WebView pointed at the live site, so a web fix reaches it without a new download.

Lekh Patro is an installable PWA with a real service worker — the typing engine, dictionary, and cheat sheet work offline. Details worth knowing:

• Install button in the header, captured from beforeinstallprompt.
• Update prompt — the app checks hourly for a new build, and when one is waiting it says so and offers to reload, rather than serving a stale shell until the OS decides otherwise. Reloading is per window: choosing "Later" in one window is not overridden by another window reloading, so unsaved editor text survives. (If a change seems missing on a phone, check the version first — Settings (the gear) → About Lekh Patro: an installed PWA can be running an older shell.)
• App shortcuts — long-press the installed icon to jump straight to Type, Translate, or Patro. These need their own icons; Android draws blank placeholders without them.
• Offline from the first visit. The worker takes control of the page that installed it, so the shell and the OCR payload are cached on the visit that fetched them rather than the one after. This is clientsClaim in the workbox config, and grep -c clientsClaim dist/sw.js is the check that it survived — switching the plugin to prompt-style updates silently drops it.

Installing the Android app on a phone with Advanced Protection

Install from Google Play and none of this applies — Advanced Protection only blocks installs from outside Play. This section is for the .apk from the releases page, on a phone without Play. On iOS or desktop you want the PWA instead.

If Android's Advanced Protection is switched on, the install will fail and the phone will not really tell you why. Advanced Protection is a single master switch that turns on several protections at once, and one of them blocks installing anything from outside the Play Store. While it is on, the per-app "install unknown apps" permission is greyed out, so there is nothing to toggle and no error worth reading — it simply will not proceed.

To install:

1. Open Settings → Security & privacy → Advanced Protection. If it is not there, search Settings for Advanced Protection — Samsung, OnePlus and Nothing each put it somewhere different.
2. Turn it off. Android will ask you to confirm.
3. Download lekh-patro.apk from the releases page.
4. Open the downloaded file. Android will ask whether your browser or file manager may install apps — allow it. (Directly: Settings → Apps → Special app access → Install unknown apps.)
5. Install.
6. Turn Advanced Protection back on. It only blocks new installs from outside Play — the app you just installed keeps working and keeps updating normally.

Step 6 is not politeness. Advanced Protection bundles real protections that have nothing to do with sideloading, and leaving it off to keep one app is a bad trade.

This is your phone's setting, not a warning about this app. Lekh Patro's signing key is registered with Google under Android developer verification (2026-09-01), so the separate friction Android applies to apps from unverified developers — a one-time setup and a one-day wait, arriving in some countries from 30 September 2026 — does not apply here.

Performance notes

Worth knowing before changing the look, all learned by measuring:

• There is almost no backdrop-filter left, and that was the point. The previous design put an ambient aurora behind everything and frosted glass on top of it. Every frosted surface sampled that aurora, so a moving backdrop meant none of the blurs could ever be cached: drifting it cost 8.8 fps against 30.9 on the Type page while scrolling, the same gap at 4x and 8x CPU throttling, so it was compositor work rather than script. Parking the drift recovered most of it; deleting the aurora and the glass recovered the rest. Blur now survives only on the app bar and the mobile dock, where the page genuinely scrolls underneath.
• backdrop-filter makes an element a containing block for its position: fixed descendants — the same rule transform carries. The app bar's blur therefore lives on .app-bar::before, not on the bar: the bottom dock is a child of the bar, and with the filter on the parent it anchors to the bar instead of the viewport and lands under the header.
• Blur the container, not the repeated child. backdrop-filter is per-element, so 76 cheat-sheet cells each carrying their own blur would be 76 blur passes. The cells are plain opaque surfaces now, which is cheaper still.

Stack

React 19 · TypeScript · Vite · Tailwind CSS v4 · Tesseract.js · @huggingface/transformers · nepali-date-converter

Run locally

npm install
npm run dev

Scripts

• npm run dev / npm run build / npm run preview — Vite
• npm run lint — ESLint
• npm run og — regenerate the Open Graph social card
• npm run icons — regenerate the PWA shortcut icons

Both generators render to public/; don't edit their output by hand.

Every change bumps the patch version in package.json (followed by npm install, so the lockfile follows). Settings → About Lekh Patro renders that version, which is the first thing to check when debugging "it isn't updating on my phone" — see the update prompt above.

Deployment is automatic: pushes to main build and deploy production on Vercel.

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More of my work: bimeshpoudel.com.np