Available on Hackage. duckdb-ffi exposes comprehensive Haskell bindings to the DuckDB C API by generating FFI shims directly from the official duckdb.h header.

• Mirrors the public C API surface, covering connections, prepared statements, result sets, vectors, logical types, appenders, Arrow integration, and more.
• Provides both raw imports and curated modules under Database.DuckDB.FFI.* so you can pick between granular or aggregate re-exports.
• Ships with an exhaustive test suite that exercises every binding to catch signature drift when DuckDB evolves.
• Validated against DuckDB 1.4-series releases. Ensure the native libduckdb shared library is installed on your system (for example via https://duckdb.org/install/?platform=linux&environment=c&architecture=x86_64) before linking a Haskell application against the bindings.

duckdb-ffi is ideal when you need precise control over DuckDB’s C API, want to interoperate with other native components, or plan to build higher-level abstractions.

Available on Hackage. duckdb-simple builds on duckdb-ffi to provide a high-level interface in the style of sqlite-simple/postgresql-simple, combining ergonomic helpers with typeclass-driven parameter binding and row decoding.

• Connection and statement helpers (withConnection, withStatement, execute, query, etc.) plus streaming primitives (fold, foldNamed, fold_, nextRow) that expose DuckDB’s chunked result processing without materialising entire result sets.
• Comprehensive scalar type coverage out of the box: signed/unsigned integers, HUGEINT/UHUGEINT, decimals (with correct width/scale), intervals, precise and timezone-aware temporals, enums, bit strings, blobs, and bignums. Standard ToField/FromField instances make round-trips seamless.
• Support for positional (?) and named ($name) parameters, with detailed diagnostics when placeholders and bindings disagree.
• FromRow/ToRow combinators—complete with generic deriving—for mapping product types to query results or parameter lists.
• Scalar function registration via Database.DuckDB.Simple.Function, allowing Haskell code (including Maybe-returning and IO actions) to be invoked directly from SQL expressions.
• Transaction helpers (withTransaction, withSavepoint) and metadata utilities (columnCount, columnName, rowsChanged).

See duckdb-simple/README.md for a step-by-step guide, extended examples, and notes on streaming behaviour and user-defined functions.