Vellor
A free, open-source tutoring tool that runs in the browser, stores everything locally, and doesn't need a server or a subscription.
SYS.STATUS: v4.0.0 shipped — offline-first, no backend, still my daily driver for tutoring ops
I kept watching independent tutors get squeezed between expensive SaaS platforms and spreadsheets that weren’t built for teaching. Vellor is my answer: a browser-based operating system for running a tutoring business without handing student data to someone else’s cloud.
Why I started this
I tutor. I’ve done it for years. The tools I kept reaching for were either overpriced, bloated with features I’d never use, or quietly shipping student records to remote servers I couldn’t audit. I wanted something I could open in any browser, use immediately, and trust with names, grades, and session notes — without a signup wall or a monthly invoice.
The constraint I set early: zero server dependency. If the network dies mid-session, the app should still work. If a tutor wants to run it on a cheap laptop with no internet, that should be fine too.
What I tried (and what broke)
I went offline-first from day one. All persistence lives in IndexedDB; state flows through Zustand with local persistence middleware so the UI feels instant on reload.
The first pain point was syncing UI state with local writes without jank. Early versions re-rendered too aggressively when filters or sorts ran on larger student lists. I profiled it, realized I was doing unnecessary work on every keystroke, and tightened the update path so filtering and sorting stay O(N) — which sounds obvious until you’re watching a 200-student roster stutter on an old Chromebook.
The PWA layer was another fight. Service worker caching is great until you ship a breaking schema change and tutors are stuck on a stale bundle. I learned to version the cache aggressively and test cold-start behavior on slow devices, not just my dev machine.
React 19 + Zustand 5 gave me fine-grained reactivity without dragging in a heavy data layer. TypeScript 5.7 caught a lot of offline mutation edge cases early — nullable fields that only surface when you’re merging partial records from IndexedDB.
Fuckups & learnings
- I underestimated how much tutors care about feel. A tool can be technically offline-first and still feel broken if a sort takes 800ms. Performance isn’t vanity here; it’s trust.
- Gamification is easy to overdo. I wanted the UI to feel alive — progress cues, satisfying micro-interactions — but not like a mobile game. Tailwind let me iterate fast; restraint took longer.
- Local-only means you own backups. No server also means no safety net. From the build, I learned to treat export/restore as a first-class feature, not a v2 afterthought.
- IndexedDB is powerful and annoying. Transactions, schema migrations, and error handling in private browsing modes — I hit all of it. The lesson: wrap storage in one layer and never let components talk to the DB directly.
Where it stands now
Vellor is at v4.0.0 — the “Power-Tutor” update. It’s a fully usable suite for independent educators: student roster, session tracking, filtering, sorting — all running client-side with no network overhead for core workflows.
Stack in production: React 19, Zustand 5, TypeScript 5.7, Tailwind CSS 3. It installs as a PWA, boots fast, and keeps data in the browser where the tutor controls it.
I’m still iterating on polish and edge cases, but the core bet — free, private, offline-capable tutoring OS — holds up.
Closing transmission
If you’re a solopreneur teacher tired of renting your own student data, clone the repo and run it locally. No account. No server bill. Just open the tab and teach.