Show HN: Rmux – A programmable terminal multiplexer with a Playwright-style SDK

Universal Rust multiplexer for the agentic era: detachable, scriptable, and inspectable, with a tmux-compatible CLI, daemon-backed SDK, and native Ratatui integration. Current release: v0.2.0, published on 18 May 2026. All 90 tmux-compatible commands are implemented, but bugs are expected — this is a fresh public preview. Please file issues if you hit one. RMUX exists because I believe the tmux use case has only been partially explored. My own starting point was simple: I wanted to run long-lived agents over SSH without losing their terminals, while still being able to inspect, script, and orchestrate everything around them. So I rebuilt that idea from scratch in Rust: a blazing-fast, tmux-compatible multiplexer with a typed SDK, persistent sessions, structured snapshots, and native local transports on Linux, macOS, and Windows, including Windows Named Pipes. No WSL required. RMUX is usable by agents, headless CLI workflows, and humans alike: you can give terminal apps detachable execution, reconnect later, inspect their state, drive them from code, or simply use it for normal tmux-style terminal work. Short, real examples of what RMUX can be used for. curl -fsSL https://rmux.io/install.sh | sh Prebuilt binary for Windows PowerShell: irm https://rmux.io/install.ps1 | iex Direct downloads and SHA256 checksums are available from the v0.2.0 GitHub Release. cargo install rmux --locked From a local checkout: cargo install --path . --locked For Rust applications: cargo add rmux-sdk cargo add ratatui-rmux Documentation The full RMUX documentation is available at rmux.io/docs. It includes installation guides, CLI references, SDK examples, terminal automation examples, and API documentation. rmux new-session -d -s work rmux split-window -h -t work rmux send-keys -t work 'echo "hello from rmux"' Enter rmux attach-session -t work Use command help locally: rmux list-commands rmux new-session --help rmux split-window --help SDK Quickstart [dependencies] rmux-sdk = "0.2" tokio = { version = "1", features = ["rt-multi-thread", "macros"] } use std::time::Duration; use rmux_sdk::{ EnsureSession, EnsureSessionPolicy, Rmux, SessionName, TerminalSizeSpec, }; #[tokio::main] async fn main() -> rmux_sdk::Result { let rmux = Rmux::builder() .default_timeout(Duration::from_secs(5)) .connect_or_start() .await?; let session_name = SessionName::new("work").expect("valid session name"); let session = rmux .ensure_session( EnsureSession::named(session_name) .policy(EnsureSessionPolicy::CreateOrReuse) .detached(true) .size(TerminalSizeSpec::new(120, 32)), ) .await?; let pane = session.pane(0, 0); pane.send_text("printf 'ready\\n' && sleep 1\n").await?; pane.wait_for_text("ready").await?; let snapshot = pane.snapshot().await?; println!("{}x{}", snapshot.cols, snapshot.rows); Ok(()) } Ratatui Widget use ratatui::{buffer::Buffer, layout::Rect, widgets::Widget}; use ratatui_rmux::{PaneState, PaneWidget}; use rmux_sdk::PaneSnapshot; fn render(snapshot: PaneSnapshot, area: Rect, buffer: &mut Buffer) { let state = PaneState::from_snapshot(snapshot); PaneWidget::new(&state).render(area, buffer); } Architecture Three public surfaces — a rmux CLI, a rmux-sdk Rust crate, and a ratatui-rmux widget — share a single local protocol to talk to the daemon. Anything one surface can do, the others can do too. Crate Role Publication rmux-types Shared platform-neutral value types public rmux-proto Detached IPC DTOs, framing, wire-safe errors public rmux-os Small OS boundary helpers public rmux-ipc Local IPC endpoints and transports public rmux-sdk Daemon-backed Rust SDK public ratatui-rmux Ratatui integration widget public rmux-pty PTY allocation, resize, child process control support crate rmux-core Sessions, panes, layouts, formats, hooks, buffers support crate rmux-server Tokio daemon and request dispatch support crate rmux-client Local IPC client and attach plumbing support crate rmux CLI and hidden daemon entrypoint public binary rmux-render-core Shared snapshot rendering core workspace-internal Platform Support Platform PTY backend IPC backend Default endpoint Linux Unix PTY Unix socket /tmp/rmux-{uid}/default macOS Unix PTY Unix socket /tmp/rmux-{uid}/default Windows ConPTY Named pipe per-user named pipe Configuration On Linux and macOS, RMUX reads .rmux.conf from the standard system and user locations: On Windows, RMUX reads .rmux.conf as well, from the following locations: The workspace is designed to be checked from source with locked dependencies: cargo fmt --all -- --check cargo clippy --workspace --all-targets --locked -- -D warnings cargo test --workspace --locked --no-fail-fast Additional local checks: scripts/cfg-check.sh scripts/unsafe-check.sh scripts/no-network-in-runtime.sh scripts/check-platform-neutrality.sh scripts/ratatui-rmux-budget.sh scripts/verify-package.sh Release artifact checks are driven by: scripts/release-local.sh scripts/package-unix.sh #![forbid(unsafe_code)] is used in the upper-level crates. OS an

Show HN: Rmux – A programmable terminal multiplexer with a Playwright-style SDK

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