Runs 100% in your browser

Try it — your file never leaves this machine

The same ~84 KB C decoder that runs inside DuckDB, Postgres and SQLite, compiled to WebAssembly. Drop a queryable .at1, read its schema, and run a zone-map-skipping query — decoded entirely on your device, nothing uploaded.

Load a .at1

Needs the fast-decode profile: at1 compress qcolumnar data.csv out.at1 --backend zstd --block-backend zstd --keep-queryable. xz-profile archives are not WASM-decodable (no lzma port) — the page will say so rather than guess.

or a hosted demo:

No .at1 handy? Make one in seconds — see getting started, or create an account for the hosted explorer.