duckdb-wasm

The DuckDB engine compiled to a WebAssembly Component (wasm32-wasip2), packaged as the reusable core that consumers embed — without pulling in the rest of ducklink.

Crates

• core (duckdb-component-core) — wraps libduckdb-sys and exports the duckdb:component/libduckdb world; compiles to ducklink_core.wasm. Its WIT contract (including the duckdb:extension import surface and the tvm:memory spill interface) is self-contained under core/wit.
• libduckdb-sys — DuckDB's C/C++ amalgamation built for wasm.

Building

Requires cargo component, the wasm32-wasip2 Rust target, and four build inputs (wasi-sdk 33.0+, the prebuilt libduckdb-wasi.a, the DuckDB headers, and the DuckDB wasm CMake build dir). scripts/setup-env.sh wires them, defaulting to the sibling ducklink checkout's prebuilt artifacts (override any var to go standalone):

make core            # standalone/server core (wasi feature)
make core-browser    # browser core (no fs shims)
make env             # print the resolved inputs (+ whether each exists)

Equivalently, by hand:

source scripts/setup-env.sh
cargo component build -p duckdb-component-core --target wasm32-wasip2 --release --features wasi

The compiled component is target/wasm32-wasip2/release/ducklink_core.wasm.

To rebuild libduckdb-wasi.a itself from DuckDB source (needs wasi-sdk), use ./scripts/build-libduckdb-wasm.sh; ./scripts/sync-core-wit.sh regenerates core/wit from a canonical wit/.

Consumers

ducklink (host, CLI, extension ecosystem) depends on this repo by path (../duckdb-wasm): its host bindgens against core/wit and loads the compiled ducklink_core.wasm at runtime.