Swimm
Agentic modernization, delivered
Overview
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.
Key Features
Deterministic Analysis: Maps dependencies and data flows across a codebase using static analysis, not just AI guesswork.
AI Agents Anchored in Analysis: Uses the static analysis output as ground truth for AI agents doing large-scale transformation.
Legacy Language Support: Handles COBOL, JCL, and PL/I alongside modern languages.
Four-Stage Engagement: Structured process from Assessment through Specification, Modernization, and Enablement.
MCP Context Layer: Feeds validated, structured codebase knowledge to Copilot, Cursor, Claude Code, and internal agents.
Air-Gapped Deployment: Available for regulated environments that can't send code off-premise.
Pricing
Starting price
Custom, fixed price per project stage; no public self-serve pricing on Swimm's own site
Engagement Pricing: Fixed price per stage of a four-stage process (Assessment, Specification, Modernization, Enablement). No public dollar figures.
Enterprise: Custom scoped pricing based on codebase size, language, and modernization goals, quoted directly by Swimm's sales team.
Disclaimer: pricing may change, confirm on Swimm's own site before buying.
Pros
Deterministic Foundation: Static analysis grounds the AI output in verified facts rather than plausible-sounding guesses.
Handles Real Legacy Systems: Genuine COBOL, JCL, and PL/I support for mainframe modernization, a niche few AI tools touch.
Compliance-Ready: SOC 2 and ISO 27001 certified, with on-premise and air-gapped deployment for regulated industries.
Proven Enterprise Clients: Established relationships with large regulated companies across finance, healthcare, and insurance.
Cons
No Self-Serve Option: No public pricing, no free tier, and no way to try it without a sales conversation.
Not for Small Teams: The whole model is built around large enterprise modernization projects, not a solo developer or small startup's docs needs.
Repositioned Product: Anyone who knew Swimm as a lightweight documentation tool will find the current product is a different, much heavier offering.
What Makes It Unique
Deterministic-First Legacy Modernization: Anchors AI agents in verified static analysis of legacy mainframe code rather than relying on generative AI to summarize systems it can't fully verify.
Kay Score
6.8
/ 10
