Product Launchllmhtml parsercoding agents
JustHTML Delivers Pure-Python HTML5 Parser With LLM-Assisted Development
8.0
Emil Stenström released JustHTML on December 14, 2025, a pure-Python HTML5 parser that passes 9,200+ html5lib-tests and reports 100% test coverage. He developed it largely with LLM-powered coding agents (Claude, Gemini) in VS Code, using test-driven workflows, fuzzing, profiling and micro-optimizations. The project illustrates "vibe engineering," where models do typing while engineers steer design and validation for production-quality code.
Key Points
- 1Passes 9,200+ html5lib-tests and provides CSS selector queries in a 3,000-line pure-Python parser
- 2Demonstrates LLMs and coding agents can accelerate complex library development with extensive test-driven engineering
- 3Encourages practitioners to adopt agentic loops, rigorous testing and profiling when using LLMs for production code
Scoring Rationale
Highlights practical, test-driven LLM-assisted engineering but scope is a single open-source library, not industry-wide standard.
Sources
Public references used for this report.
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