Rewriting Scratch 3.0 from scratch in Lua (browser-free native runtime)
Built a native Scratch 3.0 runtime in Lua that runs .sb3 projects without a browser. Why? Browser sandboxing prevents access to hardware features (haptics, sensors, fine-grained perf controls). Native runtime gives you direct hardware access and lets you deploy to consoles, handhelds, embedded devices. Also means much smaller binaries (LÖVE is ~7MB vs 50-100MB for Electron). How it works: - Scratch blocks compile to IR, then optimize, then generate Lua - LuaJIT executes the compiled code - Coroutine-based threading for concurrent scripts - Lazy loading + LRU cache for memory management - SVG…
What it does
In the maker’s words, at launch
Built a native Scratch 3.0 runtime in Lua that runs .sb3 projects without a browser. Why? Browser sandboxing prevents access to hardware features (haptics, sensors, fine-grained perf controls). Native runtime gives you direct hardware access and lets you deploy to consoles, handhelds, embedded devices. Also means much smaller binaries (LÖVE is ~7MB vs 50-100MB for Electron). How it works: - Scratch blocks compile to IR, then optimize, then generate Lua - LuaJIT executes the compiled code - Coroutine-based threading for concurrent scripts - Lazy loading + LRU cache for memory management - SVG support via resvg FFI ~100% compatible with Scratch 3.0 blocks. Extensions that need JavaScript won't work (no Music, TTS, Video Sensing), but core blocks are there. Built on LÖVE framework, so it's cross-platform (desktop, mobile, gaming devices). Still rough around the edges (user input not implemented yet, cloud variables only work locally), but it runs real Scratch projects today.
Does the same job
all alternatives →
- RPRun Python, Ruby, Node.js, C++, Lua in the Browser via x86 to WASM JIT2021 · repl.leaningtech.com · ▲171
- LLLua/LuaJIT with C/C++/Java/JavaScript syntax2018 · github.com · ▲77
- LBLuastatic – Build an executable from a Lua program2015 · github.com · ▲44
More dev tools this month
the category →
Open-source GTM skills for technical founders
Dev tools · 29d ago · gtmcofounder.com
OpenTrailPaper is open-source bike computer firmware for the LilyGO T5S3 4.7" E-Paper PRO. It supports offline maps, GPX routes, FIT recording and Bluetooth sensors.
Dev tools · 1d ago · opentrailpaper.com
Launched alongside, October 2025
the whole month →
- SA
I went down the rabbit hole on a side project and ended up building this: Strange Attractors(https://blog.shashanktomar.com/posts/strange-attractors). It’s built with three.js. Working on it reminded me of the little "maths for fun" exercises I used to do while learning programming in early days. Just trying things out, getting fascinated and geeky, and being surprised by the results. I spent way too much time on this, but it was extreme fun. My favorite part: someone pointed me to the Simone Attractor on Threads. It is a 2D attractor and I asked GPT to extrapolate it to…
AI · Oct 2025 · blog.shashanktomar.com
- ASAutism Simulator▲779
Hey all, I built this. It’s not trying to capture every autistic experience (that’d be impossible). It’s based on my own lived experience as well as that of friends on the spectrum. I'm trying to give people a feel for what masking, decision fatigue, and burnout can look like day-to-day. That’s hard to explain in words, but easier to show through choices and stats. I'm not trying to "define autism". I’ve gotten good feedback here about resilience, meds, and difficulty tuning. I’ll keep tweaking it. If even a few people walk away thinking, "ah, maybe that’s why my coworker struggles in those…
Life & fun · Oct 2025 · autism-simulator.vercel.app
