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Show HN: Rmux – A programmable terminal multiplexer with a Playwright-style SDK
Author here. RMUX started from a frustration: I've used tmux for years and got tired of scraping output with grep and sleeps to automate anything. So I rebuilt the multiplexer from scratch in Rust, with a programmable layer on top.
Two surfaces: a tmux-compatible CLI (~90 commands, your keybindings just work), and a typed async Rust SDK on the same daemon — stable pane IDs, structured snapshots, locator-style waits. The idea is Playwright-style automation, but for terminals.
Native on Linux, macOS, Windows (real ConPTY, no WSL).
Demos and docs at rmux.io. Happy to answer questions about the daemon protocol, ConPTY, or the SDK design.
- deleted 5mo ago[deleted]
- Sirental 5mo agoThe website is a little too obviously made by Claude. The first thing I noticed is the classic "pill with pulsing green dot that says something is active or live" claudism.
- redrove 5mo agoI’m genuinely interested in what you find to be the problem with that? It’s a landing page.
- xienze 5mo agoThe usual answer is some handwavy nonsense about "well if you were too lazy to write the text, why should I read it?" said by the same people too lazy to write the code...
- shideneyu 5mo agoThe video of the front page is assisted by AI, I am not a vfx artist; please check rmux code architecture instead, I put a lot of efforts on it
- powvans 5mo agoFor what it's worth I genuinely loved your landing page. I casually clicked through and got an immediate unexpected chuckle at the giant animated crab. It's obviously AI assisted but I interpreted it as a nod to itself on that and really appreciated it.
- shideneyu 5mo agoThank you ! I am proud of my little blue crab haha. I got it thanks to a lot of iteration between gpt image 2.0 and see dance 2
- saghm 5mo agoFWIW, I did suspect AI was probably used when looking through the README, but it also didn't really impact my opinion much because the value proposition of "I can use a Rust library to control this through the same primitives the tool itself uses instead of writing a bunch of shell scripts" far outweighs that. I haven't had a chance to try it out yet but plan to later today, and ultimately the experience I have is going to matter a lot more to me than what tools you used to generate the README visuals. I've tried out plenty of things that seemed promising but turned out to have sloppy implementations before the LLM days, and I've also used some things that are ostensibly vibe-coded but had shockingly high quality of UX compared to the alternatives because the creators put in time and effort into polish beyond what people who make software the "traditional" way tend to, so to me, the important signal is what level of care went into the creation of the software. I'm hoping that this project turns out to be one of the good ones, and if it is, the people who dismiss it because of vibes (pun intended) will be the ones missing out.
- vunderba 5mo agoI wouldn't worry too much about it. I think the big AI standout (not your fault) is the classic GenAI lightning that behaves more like a weird viscous liquid. Another one I see a lot is the number of avian creatures flapping their wings with all the subtlety and grace of an ornithopter going in reverse. Feedback Your site needs some work on the responsiveness. At around 1200 pixels width on my browser, half of the video just gets cut off. It just doesn't scale correctly.
- jarym 5mo agoSo?
- shideneyu 5mo ago@jarym what don't you like with the homepage ? I am curious how I can improve
- FergusArgyll 5mo agoI like it
- jarym 5mo agoI like it, and I’m not bothered if it was made with AI or not. Good work as far as I’m concerned
- Oras 5mo agoand why this is a problem? I found the landing page covering exactly what the product does, with nice demos and examples.
- cultofmetatron 5mo agocommonlisp (sbcl) is one of the best sleeper techs out there. one of those if you're in the know type industry secrets. part of it is because their website looks like something out of the 90's. clearly having a nice website and some level of marketing is necessary to get adoption. Im more than happy to see devs use AI to automate that so they have more time to focus on their creations.
- alcasa 5mo agoIsn't lisp getting advertisement every couple months here or so. After so many decades I don't believe the reason lisp doesn't have traction is just marketing.
- saghm 5mo agoGiven that Hacker News somewhat famously was written in lisp, "an advertisement every couple of months here" probably translates to an order of magnitude less in places that have a lower density of long-time lisp fans from the early days.
- stefanfisk 5mo agoNot to mention those absolutely horrible scroll animations.
- shideneyu 5mo agoyou don't like parallax effects ? maybe I'm too 2010 for you
- backwardsponcho 5mo agoI think the issue is that the parallax is choppy in your page. For whatever it's worth, I typically don't care much about parallax in itself but I thought the same thing about the scrolling not being smooth.
- stefanfisk 5mo agoI’ve never seen a scroll related animation that I didn’t hate to some degree. I suspect that the issue is that I skim and scroll REALLY fast and the animations always break the feeling of the page being a real surface. Apple is the worst offender. Some of their product pages make me physically uncomfortable like when you miscount the number of steps in a stair and step into empty air. And it’s not that I’m sensitive to animations or motion in general. Video games are no problem at all even when the physics make no sense. There’s something special about how good scrolling is on Apple’s trackpads and mobile screens which causes a really deep immersion for me. I have an Ubuntu desktop with an old school scroll wheel mouse and there the animations are just annoying but not uncomfortable.
- ookblah 5mo ago"site made by ai" is the new "bootstrap template" criticism that honestly gets tiring after a while. just read the content.
- perseusai 5mo agoAs someone new to this site, I understand wanting to keep the AI Slop at bay, but for some of us, it's been a boon to get our ideas into an actual working application. I have decades of IT/Network/Enterprise experience, but creating and writing a complex tool would have been well beyond my abilities or patience. I had a friend say that AI is a "scourge on the intellectually lazy" and I couldn't really refute that, but I had to add that it is a boon to a lazy intellectual, which I consider myself to be.
- Sirental 5mo agoI'm not saying don't use AI. It's alright to use AI in my books, I'm just saying watch out for obvious hints. Some people translate that to "this product is cheap" even if it isn't at all the case. I understand you've put a hell of a lot of work into this. You might want to have a look at https://www.awwwards.com/ https://www.awwwards.com/ and take some inspiration for some of the designs, then write up a general spec sheet of how the website should look and feed that into Claude. Otherwise Claude just does what a language model does best, and regurgitates a lot of the same styles.
- small_model 5mo agoNever had the need to do playwright automation for tmux, so not sure why I would use this above tmux which works well.
- shideneyu 5mo agowith rmux you can finally do acceptance/integration tests on your terminal user interfaces. tmux is made for humans, rmux is made for both humans and machines
- kosolam 5mo agoHey, I automate tmux all the time with send keys and capture.. how is your project improves vs tmux or zellij?
- deleted 5mo ago[deleted]
- noodletheworld 5mo agoI mean, the obvious immediate answer is “windows”, which tmux flat out doesn't support (except via WSL and a shared mount).
- Galanwe 5mo agoI don't get it as well, everything mentioned in the readme is already trivially possible with tmux or zellij
- shideneyu 5mo agowindows support + async + public sdk. You can rewrite zellij with rmux, but not the opposite. rmux is a multiplexer engine
- shideneyu 5mo agormux is much faster than tmux or zellj, I did some internal benchmark and it's promising. rmux is a multiplexer engine, meaning that you can rewrite entirely zellij using rmux.. I created a mini zellij in a few hundred lines of rust. You can check the demoes on the repo
- luizfwolf 5mo agoI found the project quite interesting but what's the advantage over just using tmux with a hotkey to send keys?
- deleted 5mo ago[deleted]
- shideneyu 5mo agowindows support, and the sdk. native async "wait until" something appears on your terminal, so you don't spam send-keys
- saghm 5mo agoWriting shell scripts to orchestrate things is not a particularly great experience. "Shell scripts are annoying to write compared to the programming languages we use for other things" isn't a universal opinion, but it's not exactly uncommon; I've heard plenty of people talk about switching to Python as soon as anything gets even moderately complex. (I often tend to go with the lines "my bar for when to switch to a real programming language is as soon as I have to write an if statement" and "the number of times I've had to write a for loop in bash is the same as the number of times I've had to google the syntax for a for loop in bash", which are only slight exaggerations). Having an actual library for interactions that isn't just a wrapper around the CLI seems like it would be a huge improvement for anything that isn't a one-off interaction.
- cultofmetatron 5mo agoa week ago I was using cmux but its osx only and doen't work on remote terminals. then I switched to herdr which is great so far except its not s great at managing panes. I can't move them around or change ordering. now another terminal multiplexer. I'm getting whiplash. all that said, none of the existing solutions are perfect and rust codebases are nice. how easy is it to reorder panes? is there a cli that lets me control the panel layout via a skill file and allow my opencode session to target and send data to other panes?
- Oras 5mo agoI started using cmux a month ago and it had made my life a lot easier. Finally I have a pane with all my projects open all the time, I can switch between them, have multiple terminals for each one. What do you mean by remote terminals?
- cultofmetatron 5mo agomy plan is to eventually move my entire workflow to a remote workmachine over ssh. with kernal, I can automate all my smoketests entirely from a headless machine rendering my laptop overkill to run agentic workflows. I'd rather be using it to watch movies, learn new stuff or hand code in my downtime. if your workflow requires cmux, you're stuck running your agents on your local machine. To be clear, That doesn't make cmux bad. if you WANT to do everythign on your mac, cmux is fantastic. its just not designed with the remote ssh control use case in mind.
- lawrencechen 5mo agoI'm one of the creators of cmux. I'm moving a lot of my own dev work to Mac Minis, so I'm starting to feel quite a lot of the pain you mentioned... will try to make this better!
- shideneyu 5mo agoplease do and let me know ! quick story fast, I'm working a loooot remotely. I'm using https://github.com/sanchxt/yoop https://github.com/sanchxt/yoop to synchronize my keyboard. Since I'm using moonlight it's blazing fast. But when I work in the train I'm back to ssh. My quick tip would be to: build your own tools, build them once, use them forever. and rmux is exactly made for that, it's prefect for TUIs over ssh and low connection that needs to stay alive even if you get disconnected
- nikhilpareek13 5mo ago[flagged]
- elromulous 5mo agoCan someone describe the pros/cons vs zellij?
- shideneyu 5mo agoYou can rewrite Zellij entirely with rmux , that's the main difference. I put a demo on the repo. Because rmux is an engine. I wrote it to be the multiplexer of multiplexers
- florianist 5mo agoThe paragraph on the website inviting us to switch to rmux from tmux claims that tmux is programmed in C++. tmux is made in C.
- shideneyu 5mo agowupsy ! thanks, I just fixed it
- DeathArrow 5mo ago1. ask Claude to rewrite X in Rust 2. ask Claude to make a website and claim R is better than X because it's Rust 3. advertise on HN, X and Reddit 4. ??? 5. profit!
- deleted 5mo ago[deleted]
- miroljub 5mo agoIf the tokens are already burned, it's better for the environment to share the result for everyone to use it.
- cat-whisperer 5mo agoI used to use ghostty's applescript and built that into a claude skill. It worked like a charm. But this feels super interesting for programmability
- 0x1ceb00da 5mo agoGetting this error when installing from git bash: $ curl -fsSL https://rmux.io/install.sh https://rmux.io/install.sh | sh rmux install: unsupported OS: MINGW64_NT-10.0-26200
- kloud 5mo agoCool project, I like the idea of having tmux-compatible CLI. I used Zellij to get better UX, but many agent tools integrate with tmux. This way agent tools can still integrate tmux as a defacto standard for programmatic interface while having better interface for users. But I wonder if tmux/rmux design is suboptimal since it couples session persistence and window management together. Do you have an opinion the design which separates the responsibilities? An example that pioneered this approach is abduco, and libghostty-based zmx being a modern implementation.
- shideneyu 5mo agoI thought I was too zealous because I created 11 crates respecting single responsibility principles.. I would have been all in to risk it further and separating responsibilities for session and window management but it would have diverged too much from tmux. I wanted a 1-1 port for now
- kloud 5mo agoFair point, given it is more unconventional design, it is a riskier way in order to get something that works.
- shideneyu 5mo agocorrect... it's sad but recognition is a lot. After putting months of efforts, it's a risk I didn't want to take. And following tmux was like a red thread of life to code. Maybe in the future !
- deleted 5mo ago[deleted]
- pama 5mo agoCongrats on the launch. If emacs was unavailable and I needed tmux, I would try it. I am old school, and use emacs daemons for all shell multiplexing. The agents dont need explanations and know how to use emacsclient to create, read, or send inputs to named buffers that run the shells. Elisp is powerful, so manipulating windows is a breeze. Lots of people on tmux would benefit from this design though.
- sroerick 5mo agoI didn't know you could do this with Emacs
- scottyeager 5mo agoIt's just too bad Emacs doesn't also include a decent text editor, right?
- smaudet 5mo agoEh? Not sure what you mean by that...
- theshrike79 5mo agoAn ancient joke: "Emacs is a nice programming language but the editor sucks"
- evanjrowley 5mo agoAre there any guides on accomplishing this with Emacs? Perhaps something that might be useful for someone coming from Tmux?
- pama 5mo agoNot sure, tbh. I use emacs -daemon to start a server; emacsclient -nw to connect. I use ssh and start a server on the remote. I spawn multiple shells with infinte buffer size and dumb terminals (M-x shell) so I can seamlessly edit. (These are based on comint, a neat command interpreter.) I use my own hacks for named shells (https://github.com/pjj/Emacs-nsh https://github.com/pjj/Emacs-nsh) and for rearranging/splitting windows, but any of the latest powerful LLMs can help with ergonomic modifications to M-x shell or the various improved terminal emulators (vterm, eat, ansi-term) or with renaming and moving/splitting windows. The Emacs manual is excellent but long; worth it IMHO, but focus on things you use. The tutorial is quick; worth it. I avoid curses programs (fancy TUI) or write wrappers around some of them. I love the -p option in codex/claude/copilot.
- notorandit 5mo agoScriptable terminal multiplexer? Interesting portable scripting thingy. But it would only work with portable tools, not just everything. Especially with Windows tools.
- shideneyu 5mo agoI wrote it for rust apps in mind, same usecase as for Ratatui. You’re right maybe I need to expose more tools with the cli
- yes_but_no 5mo agoFloating panes seems not possible, or are they?
- shideneyu 5mo agoNot part of the current version, it’s on my roadmap :)
- btown 5mo agoVery cool! I think the hype around “agents are so good that you never actually need to see the underlying commands they are running or interact with the terminal session that they’re running” misses out on a lot of very important use cases, particularly around long running processes that may be shared across multiple agents. This will be very cool to see how best practices evolve!
- shideneyu 5mo agoSame ! TUI are becoming more and more mainstream so there is a need for automated multiplexing , not used by humans but by programs (and agents)
- eddyaipt 5mo ago[flagged]
- shideneyu 5mo agoYes exactly. And it enables integration testing too. I hope it will foster the release of more cool TUIs.
- joch 5mo agoVery nice! I created `ygg`[0] a while back to easily spawn a new worktree when working with Claude/codex, and it also spawns that in a dedicated zellij tab. I think making the terminal multiplexer pluggable, so it would be easy to integrate something like this. [0] https://github.com/joch/ygg https://github.com/joch/ygg
- shideneyu 5mo agonice tool ! totally. rmux is lightweight, I believe it would be easy
- perkovsky 5mo ago[dead]
- tomaspiaggio12 5mo ago[dead]
- SwellJoe 5mo agoIt's not clear to me what this does that tmux doesn't? Agents can already interact with tmux, so what does this provide?
- gobdovan 5mo agoI think it's trying to be like a code-first/API alternative to Tmux. So instead of: ``` tmux new-session -d -s a tmux send-keys -t a 'npm test' Enter sleep 2 tmux capture-pane -p -t a ``` you'd do something like: ``` pane.send_text("npm test\n").await?; pane.wait_for_text("Tests passed").await?; let snapshot = pane.snapshot().await?; ``` I don't know why it would be better for agents, maybe the author also works on an LLM agent harness.
- shideneyu 5mo agogobdovan nailed it. The CLI is a drop-in for existing tmux workflows; the SDK eases your flow when you'd otherwise be writing brittle send-keys + sleep + capture loop. But that's just one one of the use cases. rmux should be used to make beautiful TUI, something very dirty to do with tmux. Especially the day you want to do integration testing (playwright style)
- gitaarik 5mo agoAnd what are you automating regarding your tmux sessions exactly actually? I use tmux daily, but I never feel the need to do any automation of managing my tmux panes.
- shadowfax92 5mo agothis might fit very nicely with gascity/gastown which orchestrates other coding agent over tmux. currently, i finds it's tmux orchestration code is too complex. will check it out
- shadowfax92 5mo ago> got tired of scraping output with grep and sleeps to automate anything. curious, what was the usecase here?
- shideneyu 5mo agoHehe. I am building a multi agent orchestration system of course ;) I believe this is the future, agents speaking to one each other. It's very dirty with tmux
- agentifysh 5mo ago[dead]
- abdullahob 5mo ago[dead]
- chaoticbeard 5mo agoDoes it support sixel or images at all?
- chaoticbeard 5mo agoI see that it has kitty image protocol support, will raise an issue about sixel support
- hi083 5mo agoso is this, among other things, a bypass to the recent claude -p restriction Anthropic recently shared? basically an api to a terminal?
- shideneyu 5mo agoexactly, claude-cli is just running behind the scenes in a detached way. rmux is parsing the output beautifully
- labontese 5mo ago[dead]
- mutant 5mo agozmux.