I Tried Deploying a WASM App on OSC My Apps with Codex — Here’s What Worked (and What Didn’t)

WebAssembly (WASM) is one of those technologies that feels like it should change how we build backend services — but the real question is: how well does it actually work in practice? I recently tried building and deploying a WASM-based Pixel Art Generator on OSC My Apps using Codex and the OSC MCP Connector. This post walks through the process, what worked smoothly, and where things got a bit messy. If you haven’t worked with WASM before, the idea is pretty simple. Instead of running your backend in a full container, you compile it into a small, sandboxed binary that can run almost anywhere. Compared to containers, WASM apps start almost instantly, are lightweight and portable, and run in a secure sandbox. That makes them especially interesting for serverless and edge workloads. For this experiment, I built a simple HTTP API in Rust. The app exposes a GET /health endpoint and a POST /pixelate endpoint that takes an image and returns a pixelated version. I used Codex to generate most of