Harlequin is a SQL IDE for the terminal that lets you write, execute, and explore SQL queries in your shell environment.
The tool solves the problem of needing a graphical SQL interface by bringing IDE-like capabilities directly to the command line. It provides syntax highlighting, query execution, result browsing, and database exploration through a text-based interface. The approach works by connecting to databases through pluggable adapter packages, allowing you to work with dozens of different database systems. It ships with built-in support for DuckDB and SQLite, with additional adapters available for systems like PostgreSQL, MySQL, MariaDB, and ODBC.
Harlequin suits developers and data analysts who spend time in the terminal and want to avoid context-switching to a separate GUI application. It works well for quick queries, exploratory analysis, and workflows where you're already working in a shell. The tool runs on Linux, macOS, and Windows. Installation is straightforward through standard Python package managers, with uv recommended as the primary installation method. If you need to connect to a database beyond DuckDB or SQLite, you install the corresponding adapter package into the same environment.
The project maintains active development with regular updates to core functionality and adapter support. The maintainers actively expand the ecosystem of database adapters and respond to user feedback. Documentation is comprehensive and kept current alongside the codebase. The tool receives ongoing refinement to its terminal interface and user experience based on community input.
