Three weeks ago I signed up for opencode.ai's $5 plan. I had this crazy idea: build an ES2023-compliant JavaScript engine in Rust. The result? pipa (枇杷) — a register-based VM that scores 1256 on the V8 benchmark, edging out QuickJS (1219).

The Stack

AI: opencode.ai ($5/mo first month) × DeepSeek-v4-Flash

Language: Rust (edition 2024)

Binary size: ~5.2 MB (including REPL, HTTP client, WebSocket)