DuckDB(@duckdb):When #DuckDB-Wasm was launched in 2021, databases could not be persisted: everything lived in the Wasm heap and vanished when the tab closed. Keeping data meant serializing tables to Parquet, storing the bytes in IndexedDB, and re-registering them on the next page load. This was doable, but had to be handled at the application layer and was not offered out of the box by DuckDB-#Wasm. Modern browsers now ship the Origin Private File System (OPFS), a per-origin, sandboxed file system with random-access reads and writes. DuckDB-Wasm can use it as a storage backend. This post by @carlo

2026.09.18 19:08

When #DuckDB-Wasm# was launched in 2021, databases could not be persisted: everything lived in the Wasm heap and vanished when the tab closed. Keeping data meant serializing tables to Parquet, storing the bytes in IndexedDB, and re-registering them on the next page load. This was doable, but had to be handled at the application layer and was not offered out of the box by DuckDB-#Wasm#. Modern browsers now ship the Origin Private File System (OPFS), a per-origin, sandboxed file system with random-access reads and writes. DuckDB-Wasm can use it as a storage backend. This post by @carlo_piovesan and @GeertjanW shows you how: