Swimm

Swimm used to be known as a documentation tool that kept explanations synced to the actual code as it changed, aimed at everyday developer teams. That product still exists in spirit, but Swimm has since pivoted hard toward enterprise application modernization, particularly for legacy mainframe systems written in COBOL, JCL, and PL/I. The pitch now is that deterministic static analysis, not generative AI summaries alone, extracts business rules and dependency maps from decades-old code, and AI agents work on top of that verified foundation rather than hallucinating explanations.

This makes it a very different tool than it used to be, and worth knowing before you go looking for a self-serve docs product. It's now aimed at large regulated enterprises, banks, insurers, healthcare companies, doing multi-year modernization projects, with clients like PPG, Akamai, Optum, and Merck. There's no public pricing page with dollar figures. Engagements are quoted per stage of a fixed four-stage process, which means this isn't a tool you sign up for on a Tuesday afternoon, it's a project you scope with their sales team.