# Rex Terminal Maintains 10,000 Sessions With About 3.8 GB of Memory

By Simon Yoon

Canonical URL: https://www.tokenpost.com/news/technology/27888
Published: 2026-10-08T09:25:45.000Z
Updated: 2026-10-08T09:25:45.000Z
Section: Technology

> Ghostty author Mitchell Hashimoto’s terminal is built for long-running and remote sessions, with a future target of 100,000 concurrent sessions.

Rex maintained 10,000 active terminal sessions while using about 3.8 GB of memory, demonstrating the terminal’s focus on long-running and remote workloads.

Ghostty author Mitchell Hashimoto’s terminal kept responding to user interaction during the test. Rex is designed to leave terminal tasks running in the background, including sessions connected remotely.

The team’s next target is 100,000 concurrent sessions. At 10,000 sessions, system overhead accounted for much of the remaining cost rather than the terminal itself.

One constraint involved Linux’s file descriptor table, which records open files and connections. After roughly 5,000 sessions, each new process caused the table to consume about 512 KB, even though the process used about four file descriptors in practice.

Rex addressed that allocation with C code that reduced the space used to the amount required.

The terminal also changed its approach to inactive sessions. Previously, each active session used a separate thread while waiting for data. Sessions without read activity for two seconds are now monitored by a shared thread.