Scrolls Buddy
A scrolling planner for the MapleRoyals community: per-slot scroll recommendations, stat progression, profit/loss, and session history — a real relational data layer and product analytics, with zero servers to run.
The niche
MapleRoyals is a long-running private server for an old version of MapleStory. Its economy runs on scrolling: you apply scrolls to a piece of equipment to add stats, but every scroll has a success rate, every item has a finite number of upgrade slots, and the good outcomes are rare and expensive. Chaos scrolls randomize stats instead of adding fixed ones; white scrolls protect a slot when a scroll fails. Deciding which scroll to burn on which slot — and knowing when to stop — is a real expected-value problem that players do by feel, on spreadsheets, or not at all.
Honestly, I built it because I couldn’t work the math out in my own head. I was new to scrolling, the decisions did not come naturally, and the tool was how I learned the domain — I understood the system by building the thing that reasons about it. It turned out the rest of the community had the same gap. So Scrolls Buddy does what I wanted for myself: pick an item, and it gives you per-slot recommendations, visualizes the stat progression, and tracks the profit or loss of a scrolling session against live market prices. It sits at scrolls.itaywol.tools.
The constraint I set myself
A niche tool for a game community has an audience measured in dozens, not thousands. That number decides the architecture before anything else: I was not going to stand up, secure, and pay for a backend to serve twenty people a day. The constraint became the design brief — no servers, no database to operate, no bill that scales with traffic — and the interesting part was refusing to give up any real capability to honour it.
The result is a fully client-side application. Everything a backend would normally do happens in the browser tab.
The approach
A real database, in the browser. Session history, saved item configurations, and
scrolling outcomes are relational data with real queries behind them — the kind of thing
localStorage handles badly the moment you want to ask a question of it. So the app runs
SQLite compiled to WebAssembly, persisted into the browser via IndexedDB. It is
genuine SQL against a genuine database; the data simply lives on the user’s device and
never leaves it. No rows on a server means nothing to breach, migrate, or back up.
Game data pulled, not hosted. Item names, icons, and base stats come from public game-data APIs (maplestory.io and the MapleRoyals wiki) on demand, cached at Cloudflare’s edge. I host no assets and maintain no scraper — the canonical sources stay canonical, and the app stays a thin client over them.
Analytics without a server. I still needed to know whether anyone used the thing, and
which features earned their place. The app sends product events to PostHog, but through a
first-party /ingest path on its own domain rather than to PostHog directly — which keeps
the telemetry first-party, survives ad blockers, and still runs no infrastructure I own.
That feed is how I know it holds a steady ~20 daily active users, and which parts of
the planner they actually reach for.
Installable and offline. Because the data layer and the logic are entirely local, the app is a PWA: installable, and fully usable without a connection once the game data is cached.
The stack
React and Vite for the SPA, Radix UI primitives for accessible components, SQLite-WASM
for persistence, PostHog for analytics, and Cloudflare Pages for hosting — a static
bundle on a global edge, deployed on push, on the scrolls.itaywol.tools subdomain of a
domain I already manage. The whole thing costs nothing to keep running.
Why it worked
The tool found its users the honest way: I dropped it in the MapleRoyals community and Discord, and people who scroll gear kept it open. A steady handful come back every day, and a few thought it useful enough to leave a tip — the clearest signal a free tool can get.
The lesson I keep relearning: a sharply-scoped thing built for a real, specific need beats a general thing nobody asked for. Scoping it to twenty people is exactly what let it be serverless, free to run, and finished — rather than an ambitious platform I would still be maintaining and paying for.