cs51.io

cs51.io is a live English-language website hosted on Fastly, Inc. (AS54113) in the United States, served by Github.com. cl0q first saw it on 2026-07-02 and last crawled it on 2026-07-20. It resolves to 185.199.110.153 and has mail (MX) records set up. Its favicon is fingerprinted by SHA-256, so you can find every other site that serves the same icon.

How the site describes itself:

Home | Abstraction and Design in Computation

Description # The goal of CS51 is to give you insight into the difference between programming and programming well. One and the same problem can be solved in different ways, and the different solutions can vary along multiple dimensions including correctness, readability, testability, maintainability, scalability, efficiency, and elegance. Optimizing across all these dimensions requires judgement, but pays off abundantly. Whether you’re writing code yourself, collaborating with other software developers, or vibe-coding with a coding agent, it’s crucial to know whether a program is written well.