TL;DR: With one prompt, I built an implementation of IndexedDB using Claude Code and a Ralph loop, passing 95% of a targeted subset of the Web Platform Tests, and 77.4% of a more rigorous subset of tests. When I learned that two simple browser engines had been vibe-coded, I was not particularly surprised. A browser…

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An experiment demonstrates building a complete IndexedDB implementation from scratch using Claude AI with a single prompt and automated iteration loop. The implementation passes 95% of targeted Web Platform Tests and 77.4% of a more rigorous test suite, achieving results comparable to fake-indexeddb (82.8%) in just a few hours. The project cost approximately $7 and produced 4,395 lines of TypeScript code backed by SQLite. While the code quality is reasonable and the approach leverages Web Platform Tests as acceptance criteria, the author reflects on how AI tools are devaluing traditional software development efforts while acknowledging their inevitable dominance in the field.

Building a browser API in one shot