#30: Porting Legacy VB6

September 29, 2026

Businesses still rely on aging software that can be expensive, risky, and sometimes nearly impossible to modernize. In this episode, Andy challenges Claude Code to take a 20-year-old Visual Basic 6 application and port it to a modern Rust backend and web-based frontend in a single day. Within hours, AI analyzes the old codebase, creates a plan, writes tests, makes dozens of commits, and produces a working application.

But getting something that works isn’t the same as getting something that’s correct. Dustin and Andy explore the risks of AI-driven legacy modernization, including missing requirements, undocumented business logic, AI making thousands of decisions without human input, and tests that can confidently validate the wrong behavior. AI could dramatically reduce the cost of modernizing legacy software, but subject matter experts, careful requirements, testing, and human review remain critical when the software actually matters.

Play the AI-Ported Game

Curious how well AI handled porting a 20-year-old VB6 codebase? Try the game for yourself!

Using Claude Code, the original Visual Basic 6 engine was rebuilt with a modern Rust backend and browser-based frontend. For this demo, the backend was compiled to WebAssembly and runs entirely in your browser, so no cloud server is required.

There was one interesting catch: the original source code didn’t include the game’s maps or other critical data files. That meant Claude couldn’t faithfully recreate the original world, so it built a new one based on the surviving code and available references. We then play-tested the result, prompted Claude to improve the gameplay, and incorporated free game assets and sounds.

Play the game

🔗 Resources and mentions from this episode:

  • Visual Basic 6 (VB6)
  • Claude Code
  • Anthropic
  • Rust
  • TypeScript and React
  • OpenAI Codex Adversarial Review
  • Git and GitHub
  • CrystalShire
  • Eclipse Origins
  • Docker Compose
  • AI coding agents

👉 Want more practical insights on using AI in your business? Subscribe to the podcast, follow us on YouTube, or explore past episodes at modernlogic.io/podcast.

💬 Let’s Talk AI!

Have legacy software that’s becoming difficult or expensive to maintain? Modern Logic can help you explore where AI can accelerate modernization while making sure the result actually works for your business.

Book a free 30-minute consultation at molo.now.

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