Nex

Record your terminal, replay it, or stream it live to anyone with a browser. Nex is a Rust tool that captures terminal sessions into a compact .nex file, and can share a live terminal across the internet with playback rendered by Xterm.js.

Live demo: https://nex-terminal.netlify.app

Screen recordings of terminals are the wrong tool: they are enormous, blurry, and you cannot copy text out of them. A terminal session is really just a stream of bytes and timestamps, so that is what Nex stores.

How it works

flowchart LR
    T["Your terminal<br/>(PTY)"] --> R["nex recorder<br/>bytes + timestamps"]
    R --> F[".nex file"]
    R --> S["Async server<br/>Tokio + Warp"]
    S -- "WebSocket" --> V["Viewer's browser<br/>Xterm.js"]
    F --> P["Playback<br/>seek · speed control"]
    P --> V

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Recording wraps your shell in a pseudo-terminal and logs output with timing information. Sharing pipes the same stream over a WebSocket, so a viewer's browser renders your terminal live, as text — selectable, copyable, and a fraction of the size of a video.

Usage

cargo build --release

nex start -o demo.nex          # start recording (default: recording.nex)
nex stop                       # stop the current recording
nex play demo.nex              # replay in your terminal (--show-commands for command markers)
nex inspect demo.nex           # examine a recording's contents
nex csv demo.nex               # export the session as CSV
nex json demo.nex              # export the session as JSON

nex serve 8080 --web           # host a collaborative session with a web UI
nex catch <host> 8080          # join someone's session from another terminal

serve --web exposes an HTTP + WebSocket interface on the same port, so a viewer needs nothing but a browser; catch joins from another terminal. Playback in the browser supports seeking and speed control, which video-based recordings make painful and plain-text logs make impossible.

Why not asciinema?

Asciinema is excellent, and Nex is deliberately in its lineage. Building my own taught me the actual mechanics — PTY handling, timing capture, escape-sequence passthrough, async fan-out to multiple viewers — and gave me a self-hostable live-sharing mode with no third-party service in the loop.

Honest limitations

• The .nex format is my own; there is no converter to or from asciicast yet
• Live sharing trusts the link — anyone with the URL can watch; there is no authentication layer at present
• Interactive input from viewers is intentionally not supported: it is a window, not a remote shell

Stack

Rust · Tokio · Warp · WebSockets · Xterm.js

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Built by Aryan S Rao. Issues and pull requests are welcome.