Show HN: legacy-use – add REST APIs to legacy software with computer-use

Hello HN! Sebastian here from Schub.

We just open-sourced a new project I've been working on, called legacy-use, and I’d love to get your thoughts.

At Schub, we’ve been building agents that automate legacy Windows software (healthcare systems, finance tools, EHRs), the kind of stuff that’s mission-critical but hasn’t changed since Windows XP. These apps have zero APIs and usually require humans clicking around all day.

So we built legacy-use, an agentic API layer for any desktop app. Well, technically any software. Legacy-use lets AI agents control GUI-based software by emulating mouse and keyboard input, with full visual feedback. Just like UIPath, but more error tolerant. It builds on Anthropic’s Computer Use and extends its’ capabilities to old legacy tools on Windows / Linux / whatever systems.

How it works:

- We build the infrastructure to connect to legacy systems (like RDP / VNC + VPNs) and handle the queing - We execute prompts to the target systems and handle all the logging / monitoring - We allow the agent to extract data and expose it as a REST API. - We build in guardrails, so if something goes astray a human operator can be called in

We’ve already seen some pretty fun real-world uses:

- A medical provider automated 30% of their admin work using GPT + legacy-use - An accounting firm hooked it into a 2009 finance app and now generates compliance reports fully hands-off

What excites me: so much of our GDP generating industry relies on legacy software to run their business. And that’s not about to change any time soon as this software is so targeted to their use-case. So for them to profit from the automations that the agentic revolution will bring about, they need to open up their legacy systems. That’s my vision: allow access to any existing IT system so companies can participate in the agentic revolution.

Here’s the repo: https://github.com/legacy-use/legacy-use

Would love your feedback and I'm super happy to chat if you want to pioneer a use case. If you’ve got some old internal apps you’ve been dying to automate, happy to help you wire up your first flow.

Let’s bring legacy software into the agentic era.

— Sebastian