How Other Link Checkers Do Recursion (opens in new tab)

After I published , one reply I got was a very fair question: If recursion is so hard, how do other link checkers do it? Plenty of them already crawl websites! This sent me down a rabbit hole of reading the code of other link checkers. The key takeaway is: they didn’t find a clever trick we missed. They were built as crawlers from the very first commit, and I initially built lychee as a stream. I went and read the source of the recursive checkers we list in : If you haven’t read the , the sum...