Live Demo

haystackfm runs entirely in your browser. The demo builds an FM-index (on the CPU or the GPU via WebGPU), runs count / locate queries, and serializes the index — all client-side, with nothing uploaded to a server.

What you can do

1. Input sequences — paste plain ACGT lines or FASTA, or load the bundled example.
2. Build — construct the index on the CPU or, if your browser supports WebGPU, on the GPU.
3. Search — enter a pattern and see the occurrence count and located positions.
4. Serialize — export the built index to bytes and reload it, exercising to_bytes / from_bytes.

Requirements

The GPU build path needs a browser with WebGPU (Chrome/Edge 113+, Safari 18+, Firefox behind a flag — see Browser Support). The CPU build works in any browser that runs WebAssembly; the demo detects WebGPU and enables the GPU button only when it’s available.