What Is the PostgreSQL Online Compiler?
This is a browser-based PostgreSQL query tool powered by PGlite, a real PostgreSQL engine compiled to WebAssembly. You can run actual PostgreSQL queries with full SQL compliance directly in your browser without installing anything. Results display as formatted tables so you can instantly verify your queries.
How It Works
When you open the page, PGlite WASM loads a real PostgreSQL engine (approximately 3 MB) into your browser. Write SQL in the CodeMirror editor, click Run, and see results rendered as tables. The engine supports standard PostgreSQL syntax including CTEs, window functions, JSON operations, and advanced data types like arrays and JSONB.
Step-by-Step Example
- Create a table using
CREATE TABLEwith columns and constraints. - Insert sample data with
INSERT INTOstatements. - Run a
SELECTquery with aJOINto combine data from multiple tables. - Use a CTE (
WITHclause) or window function likeROW_NUMBER()to perform advanced analysis. - View the formatted table results in the output panel.
Use Cases
- Learning PostgreSQL syntax and features interactively
- Testing complex queries before running them on production databases
- Practicing CTEs and window functions for advanced SQL skills
- Preparing for database interviews with hands-on query practice
- Prototyping schema designs and validating table relationships
Limitations & Notes
- Runs PGlite WASM entirely in the browser, so no server-side processing is involved.
- Some PostgreSQL extensions (PostGIS, pg_trgm) are not available in this environment.
- All data resets when the page is reloaded; there is no persistent storage.
- No network access or external database connections are supported.
- Performance may vary depending on your browser and device.
- This tool is intended for learning and testing, not for production workloads.
Frequently Asked Questions
Is this a real PostgreSQL engine?
Yes. PGlite runs actual PostgreSQL compiled to WebAssembly in your browser, providing real SQL compliance and behavior.
Does this support CTEs (WITH clauses)?
Yes, common table expressions work fully. You can write recursive and non-recursive CTEs just like in a standard PostgreSQL installation.
Are window functions supported?
Yes. ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, and other window functions are all available and work as expected.
Is my data persistent?
No. All tables and data reset when the page reloads. Each session starts with a fresh database instance.
Does this support JSON operations?
Yes. PostgreSQL JSON and JSONB operators are available, including path extraction, containment checks, and JSONB manipulation functions.
Can I use CREATE TABLE and ALTER TABLE?
Yes. Full DDL support is included. You can create tables, alter columns, add constraints, create indexes, and define views.
What PostgreSQL version is this based on?
PGlite is based on a recent PostgreSQL version compiled to WebAssembly, supporting modern SQL features and syntax.
Does this support transactions?
Yes. BEGIN, COMMIT, and ROLLBACK statements work, allowing you to test transactional behavior in your queries.