CQL Playground

This live CQL sandbox allows you to write and execute Clinical Quality Language (CQL) queries directly in your browser using the FHIR4DS engine.

info

This playground uses synthetic sample data for 28 patients. To test against real EHR data, visit the SMART on FHIR Demo.

Features

• Live Translation: See the optimized DuckDB SQL generated from your CQL in real-time.
• In-Browser Execution: Queries run directly against a local DuckDB-WASM instance.
• Verification: Use the Patient Data pane to inspect raw FHIR resources and verify query results.