I built a vector search library in Rust/WASM. Here's what I learned about performance, browser limits, and building in p

I wanted to build a privacy-first RAG app. The kind where your documents never leave the browser. It means no API keys, no server, no third-party vector database watching what you search for. The architecture was obvious: embed documents client-side with something like Transformers.js , store the vectors locally, and search them with cosine similarity. Simple enough. Except the "search them" part fell apart at about 5,000 vectors. Pure JavaScript vector search has a ceiling, and it's lower than