From VS Code to Zed: building a FreeMarker extension because I needed one

# From VS Code to Zed: building a FreeMarker extension because I needed one A few months ago, I switched from VS Code to **Zed**. Not because VS Code is bad — it’s still an amazing editor — but because it slowly became… heavy. My setup had turned into a Frankenstein monster of freemium extensions, background processes, upsells, and “just one more helper” that somehow made everything slower.  I wanted something: - fast - open-source - opinionated - boring in the best possible way Zed checked all the boxes. Until I had to start working with **FreeMarker**. --- ## FreeMarker is still very much alive If you work in Java or enterprise environments, you already know this. FreeMarker isn’t trendy. It’s not on Hacker News every week. But it’s **everywhere**. In my case, I’m using it in a project that integrates **Keycloak**, where FreeMarker templates are still a core part of the customization flow. So yes — FreeMarker is old. And yes — it’s still critical. Which made this part a bit painful: 👉 **Zed had no FreeMarker support.** No syntax highlighting. No understanding of directives. Nothing.  --- ## The “fine, I’ll do it myself” moment Zed is fast enough that once you get used to it, going back feels… wrong. So instead of switching editors again, I thought: > “How hard can it be to write a FreeMarker extension?” (Last words before opening a tree-sitter grammar.) I already knew that: - Zed uses **tree-sitter** - Syntax highlighting is grammar-driven - Extensions are lean and explicit I also had a starting point: a **FreeMarker extension for VS Code**. The idea was simple: - reuse what I could - adapt what I had to - learn the Zed extension model along the way With some help from **vibe-coding** and a lot of trial & error, I started porting it. --- ## The actual journey (a.k.a. tree-sitter reality check) Some things were easier than expected: - Zed’s extension model is refreshingly clean - Tree-sitter forces you to think properly about structure - No magic, no hidden layers Some things were… not: - FreeMarker syntax is flexible in *annoying* ways - Directives, interpolations, nested expressions - Edge cases you only notice after breaking everything Porting from VS Code wasn’t a copy–paste job. It was more like translating between two different mental models. But honestly? That’s what made it fun.  --- ## The result: early, but usable The extension is live here: 👉 **https://github.com/debba/zed-freemarker** What it supports today: - FreeMarker syntax highlighting - Directives - Interpolations - A solid base for further improvements Is it perfect? No. Is it production-grade? Not yet. Is it **good enough to work daily without hating your editor**? Absolutely. And for an editor like Zed, that already feels like a win. --- ## Thoughts on Zed and niche tooling Zed feels like an editor for people who: - enjoy understanding how their tools work - prefer fewer abstractions - don’t mind building missing pieces themselves Writing this extension reminded me of something important: > Open source doesn’t move forward only with big features — > it also grows through small, boring, niche tools that solve real problems. FreeMarker isn’t cool. But someone still has to maintain it.  --- ## What’s next? Possible next steps: - better grammar coverage - error handling - maybe an LSP in the future (no promises) If you: - use FreeMarker - use Zed - enjoy hacking on developer tools Feedback, issues, and PRs are more than welcome. Sometimes the best extensions start with a simple need: > “I just want my editor to understand this file.” And that’s exactly how this one was born 🚀