OPFS + Pyodide test harness

📰 Simon Willison's Blog

Learn how to use OPFS and Pyodide to create a test harness for editing persistent SQLite files in the browser, and why it matters for Datasette Lite development

advanced Published 23 Jun 2026
Action Steps
  1. Set up a Pyodide environment using WebAssembly
  2. Configure OPFS to store and manage SQLite files
  3. Build a test harness using OPFS and Pyodide
  4. Run the test harness to validate Datasette Lite's functionality
  5. Test and iterate on the setup to ensure seamless editing of persistent SQLite files
Who Needs to Know This

Developers and testers working on Datasette Lite and similar projects can benefit from this setup to test and validate the application's functionality, especially when it comes to editing persistent data

Key Insight

💡 OPFS and Pyodide can be combined to create a powerful test harness for editing persistent data in the browser

Share This
🚀 Create a test harness with OPFS + Pyodide to edit persistent SQLite files in the browser! 💻

Key Takeaways

Learn how to use OPFS and Pyodide to create a test harness for editing persistent SQLite files in the browser, and why it matters for Datasette Lite development

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