I Built 21 Browser-Based Dev Tools in Pure HTML/CSS/JS — Here's What I Learned

About three weeks ago I shipped DevCrate — a collection of 21 developer utilities that run entirely in your browser. No login. No backend. No frameworks. Just HTML, CSS, and vanilla JavaScript. I want to be honest about how it went, because most "I built a thing" posts make it sound cleaner than it was. Why I built it I kept reaching for the same tools every day. A JSON formatter. A JWT debugger. A cron expression builder. And every time I landed on a site that wanted my email address, showed me ads, or sent my API payloads through their server, I'd close the tab annoyed. So I built the version I actually wanted. Browser-only. Fast. No accounts. No tracking. What I thought would take a weekend took three weeks. Here's what slowed me down. The thing that actually broke me: CSS consistency across 21 tools I expected the hard part to be the JavaScript — the JWT parsing, the regex engine, the diff algorithm. That stuff was fine. The thing that genuinely ground me down was keeping 21 pages