Mock Everything, Measure the Right Thing: aimock, Rust-to-TypeScript Parser Rewrite, and a CSS Percentage WTF
Published on 10.04.2026
aimock: Mock Everything Your AI App Talks To
TLDR: CopilotKit released aimock, an open-source TypeScript library that mocks the full stack of external services an AI app communicates with. LLM providers, MCP tools, agent-to-agent protocols, vector databases, and search APIs -- all on a single port, zero external dependencies.
GitHub - CopilotKit/aimock: Mock everything your AI app talks to
Rewriting a Rust WASM Parser in TypeScript Was the Right Call
TLDR: The OpenUI team rewrote their Rust-compiled-to-WebAssembly parser in TypeScript and got 2.2x to 4.6x faster per-call performance. The bottleneck was never the parsing logic -- it was the JavaScript-to-WASM boundary overhead every time they crossed it.
Rewriting our Rust WASM Parser in TypeScript
Take a Percentage
TLDR: A major news site's CSS contains the padding value 57.14285714285714% derived from a 560:320 video aspect ratio. It is technically correct. It is also delightfully absurd.