# Mark Phelps

> Mark Phelps is creator and maintainer at Offscreen. Offscreen on Anchor Terminal, with grades, an about and public profiles.

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- JSON: https://www.anchorterminal.com/people/mark-phelps/index.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-10-27

Creator and maintainer, Offscreen.

Mark Phelps builds Offscreen, which runs macOS UI tests and GUI apps for coding agents in throwaway virtual machines. He works on the AI infrastructure team at Cloudflare, previously ran his own startup, Flipt, and before that helped build GitHub Container Registry.

- LinkedIn: https://www.linkedin.com/in/markphelps1
- X: https://x.com/itsmarkphelps
- GitHub: https://github.com/markphelps

## What Mark builds

- [Offscreen](https://www.anchorterminal.com/tools/offscreen.md), graded B, 63.4/100, in Code execution sandboxes. Offscreen is an open-source macOS command-line tool, daemon and menu bar app that runs a coding agent's UI tests, iOS Simulator runs and GUI app launches in a fresh Tart virtual machine per job, away from the user's desktop. Creator and maintainer, Offscreen, founder, researched 2026-10-27.

## Questions

### Who is Mark Phelps?

Mark Phelps builds Offscreen, which runs macOS UI tests and GUI apps for coding agents in throwaway virtual machines. He works on the AI infrastructure team at Cloudflare, previously ran his own startup, Flipt, and before that helped build GitHub Container Registry.

### What does Mark Phelps (independent) make?

Anchor Terminal lists Offscreen from Mark Phelps (independent). Offscreen is an open-source macOS command-line tool, daemon and menu bar app that runs a coding agent's UI tests, iOS Simulator runs and GUI app launches in a fresh Tart virtual machine per job, away from the user's desktop.

### How are Mark's tools graded?

Offscreen is graded B, 63.4 out of 100, on Anchor Terminal's benchmark, which scores every listing against the same checklist.

## Sources

- https://raw.githubusercontent.com/markphelps/offscreen/main/README.md
- https://raw.githubusercontent.com/markphelps/offscreen/main/LICENSE
- https://markphelps.me

These are the people building the tools we list, named for their public role in the company or project behind a listing, from public pages, with the date it was researched. They don't work for Anchor Terminal (our own team is on the about page, /about/#author). We show public roles, public profiles and what the listing pages show, nothing private. To correct something, send an about or a photo, or have a page removed, write to privacy@anchorterminal.com.

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