Show HN: Petal, open-source CoScreen/ScreenHero finally free
petal.liveHi HN!
I’m Jason Thomas, one of the founders of CoScreen.
As some of you may know, Datadog sunset the CoScreen service on July 31st.
Four of us from the original CoScreen team have spent the last couple months building a free and open source pair programming tool inspired by those that came before us: It’s called Petal (https://github.com/kiruna-labs/petal)
Some history first, because when we started CoScreen we had hoped to break the sad and established pattern of this industry.
Screenhero was an exceptional tool that a lot of us loved for pairing. Multiple cursors, low latency, you could click your partner’s editor, and just start typing. It felt like magic while we had it. Then Slack bought it in 2015, and shut down the standalone app in December 2017.
When Till, Max, and I started CoScreen, we were aware of this history, and wanted to build an even more magical collaboration and screen sharing experience: the entire concept was “throw a window from your laptop up on someone else’s screen, and start collaborating with zero friction.”
Datadog acquired us in 2022, and thus began the great adventure of adapting our real-time technology into Datadog products, while also continue developing CoScreen as a standalone tool from the Datadog ecosystem. Datadog invested in the product for years and we’re thankful for that. But CoScreen itself proved, like so many other screen sharing tool acquisitions, to be too tangential from the customer base and core mission. We instead built other communication features in Datadog, the integrations with other video platforms, and also its wildly successful MCP server. We weren't the only ones. Around was bought by Miro and shut down in March 2025. Multi (formerly Remotion) was acqui-hired by OpenAI in 2024 and shut down about a month later. It's nearly always the same story: a small team builds something hard that people love, a platform buys it for the team or the feature, and the standalone product doesn't survive the integration. So we decided firmly to do things differently this time. Petal is completely free and open source and we aren't monetizing it. If we lose interest or get hit by a bus, you can self-host it or fork it, and nobody can sunset it on you. Honestly it's a love letter to everyone in this community that supported us, believed in us, and to liberate collaborative screen sharing from this vicious cycle.
We hope through this we can help foster a large and vibrant community around innovating in this product sector. What Petal does: shared windows show up as real windows on your desktop, movable and resizable, not tiles in a grid. Several people can share at once, everyone gets a labeled cursor, and you can click into any shared window to type and scroll. Rooms are persistent, so you click once to join "eng-sync" instead of passing links around. It runs on macOS and Windows (Linux is next, this time for real and you can help us!), plus a web app. Media goes over LiveKit. You can use our hosted instance with zero config, or point the app at your own LiveKit server with one docker-compose if you want the traffic to stay on your network or even use an entirely different video backend if you want to. The part that still feels strange to us: CoScreen took almost six years to build. The first version of Petal took under eight weeks, from scratch, with frontier models like Fable and Astra doing a lot of the work. Real-time video and window capture is some of the most unforgiving code we have ever written, so we didn't expect that. We will do a proper writeup on what worked and what didn't, and are happy to answer questions about it here. Till, Darren, Max and I will be in the thread.
Screenhero co-founder/CEO here — this is really great! It looks like we had similar feelings after leaving our acquiring companies with our products being sunset.
Since leaving Slack, I've been building Pop with a new team. The first product we launched in 2020 is essentially Screenhero 2.0 (pop.com). Since then, we've been building an expanded product: a virtual office for remote teams, which is now almost ready for launch (there's a waitlist at https://new.pop.com). We've even got Wayland support in! We have plans to open source a part of the Wayland piece, which Petal could potentially use too.
I do love this space, and wish more tools were about live collaboration — it feels so much more human and fun than single-player mode. I hope Petal becomes a growing community that thrives for the long haul!
Amazing to see you here.
Folks looking for Linux support, check out J's work!
Omg I thought Pop was dead. We used it for literally years. Even emailed support multiple times asking if dead. Wtf???
How does the virtual office compare with something like Gather (https://www.gather.town/) ?
Nice! Will pop it up. Great name!
Till here, another co-founder of CoScreen. Like Jason wrote, our launches on HN and the feedback by many of you in 2019 were really important all the way back to the earliest days of our small and fancy tool. We did a lot of things since we're proud of but a few plans remained unfulfilled, like support for Linux, until now.
We'd love to work with you and see what you'll build, now that Petal is out in the open for anyone to use, jam on, and make it your own.
Very very happy to see this!
I was lucky to work with Till+Jason on CoScreen (I came in late); they're really exceptional people and CoScreen had a great collaboration UX that still hasn't been matched by Zoom and friends. Really keen to see what they'll be able to build this time around.
Thank you for this, I am a big fan of pair programming, and even jetbrains is getting rid of their code-with-me service! It’s so Frustrating to see a useful feature/tool get abandoned due to low usage. But those of us who use pair programming absolutely love it :)
It’s a tool that helps further human connection, imo. And we could all use a little more of that atm.
It's crazy because we dogfood Petal daily, and did so with CoScreen while it was alive... and we absolutely cannot live without it.
I'm in Utah, and Till is in CA, so it's vital to our daily work.
Truly I don't understand how people do remote work or collaboration these days... maybe they don't? Or maybe Zoom/Meet are good enough (I really truly think they aren't, it's an abusive horrible experience every time I am forced to use Zoom or Meet for anything).
There just seems to be something sticky about them, but the people who try a CoScreen, Tuple, Pop, or other tool designed around collaboration I think become converted permanently, but getting people into that funnel is very very hard.
Reminds me of Tuple (https://tuple.app/), which was also billed as a Screenhero replacement
True, another great app in the space
<3
This is just what we need in our small startup. It solves problems we have when working remotely and joint debugging along with walking our customers through tricky issues. Can't wait to give it a spin
Please do and leave your feedback on the repo or submit through the app. Any contributions are appreciated
Thank you for your work, looking forward to the Linux version!
Fingers crossed this time. Leave an issue on the repo if you have any specific wishes/distros to support or also want to contribute. Most of Petal is OS agnostic so it would be at least easier than ever to make it happen
Just want to say thank you!! Screenhero was invaluable. Pop is pretty good, but open source is a game changer!
Interesting. Was sad to see so many products in this area sunset (most after acquihires).
I wonder if tools built around multiplayer LLM work won't win out though?
Any thoughts on how this compares to https://delta.dev/ ?
Thanks for making this. We used co-screen so much that when you shut down, we had to build our own.
Haha. I think I know who this is, and I won't out you, and thank you so much for your support over the years!
Maybe you can contribute some of your private innovations upstream to Petal ;)
Trying to view https://www.coscreen.co/ and seeing:
"www.coscreen.co uses an unsupported protocol"
SSL Labs report: Assessment failed: Failed to communicate with the secure server https://www.ssllabs.com/ssltest/analyze.html?d=www.coscreen....
Yeah, Datadog sunset CoScreen in July.
You can view it here for nostalgia reasons: https://web.archive.org/web/20260828162646/https://coscreen....
Will give it a try! How is LiveKit working for you in terms of achieving low input2video latency? Did it lend itself to getting tuned for this application?
One of our engineers is working on a very low latency video/audio mode for gaming. The truth is Petal isn't yet as tuned as say CoScreen was for low latency.
It's on our product roadmap to have a mode to support this though.
Some of our engineers have discussed a totally p2p iroh based video transport and other ideas.
LiveKit was the fastest/easiest way to get it to market, and it was something Till and I volunteered to pay for at the moment so we have an off-the-shelf cloud offering that is free and usable.
From that perspective it has worked great.
As is common with lots of software like this, unfortunately, it looks like this product doesn't support Japanese/CJK text entry (with an IME popup and multiple input sources). This is a deal breaker for the Japanese/Chinese speaking market.
It is not impossible to support as there are other apps that do properly support Japanese text entry. I was excited for an open source product for the reasons OP noted, but I'm very disapointed that it does not support my use case.
Is there any plans for adding full international text entry support?
Thanks for the feedback! This was one of the areas where CoScreen was strong.
We will take your feedback and see what we can do.
The self-hosting guide currently calls for running the token backend as well as LiveKit, then rebuilding the desktop app with the backend URL baked in. Is there a way to switch the released app to a self-hosted backend without rebuilding?
Feel free to try Hopp[1], which supports self hosted backends without having to rebuild the client. Selfhosting takes literally less than 5 minutes.
[1] https://github.com/gethopp/hopp
(disclaimer I am one of the maintainers)
I really wonder if it’s just me, but I have a deeply visceral reaction to AI copywriting that is largely irrational I’m willing to admit.
> The media server — traffic stays yours
The product looks cool! It’s just… reading that sentence makes me __immediately__ lose all interest.
Lol. Yes, all of the Mic-drop crap.
We can work on it. Obviously it's Till and I working on the copy, and unashamedly we are using Claude to help expedite it so we can focus on the fun stuff... but yes, I absolutely hate this crap too.
Thanks for the honesty! I don't blame you, it's hard to write good copy.
Cheers and good luck!
It's understandable, I don't think most of us like getting to the actual documentation of our project and would rather keep coding and/or prompting.
I think this is a message more for everyone that feels this way than just you but...
I'd suggest having a model go through it using pstack's unslop skill and see if you like that copy better.
But in all honesty we should be proofreading readmes before sending instructions out to millions of people. I've tried setting up a few that just didn't work when following instructions because of incorrect info or just completely leaving necessary steps/info out... Usually totally useless info in its place.
There's a conundrum there where we're so excited to show off our project that we present it in this streamlined way that makes people unable (or unwilling) to even digest what it's for and how to properly set it up.
You know what they say about first impressions.
https://github.com/cursor/plugins/blob/main/pstack%2Fskills%...
https://github.com/michael-denyer/pstack-claude
This is super cool and thanks for open sourcing. I remember seeing CoScreen & Screen Hero here on HN years ago and thinking it was absolutely the cat's pajamas. Unfortunately, I think it was one of those cases of being blinded by the tech being super cool.
Of the ~decade since I've seen these types of apps, I've never used one and, frankly, I never ever craved for "just sharing one window" or "playing in multiplayer" as @jsherwani put it. Which is kind of odd, because COVID came and went (peak remote/screen sharing days), and I had totally forgotten these kinds of products even existed. While this is (still) super neat technically, I just don't really see a concrete use case other than "lemme show you something super cool."
Has anyone actually used it? Where would this kind of tool be better than just screen sharing over Google Meet or Discord or Slack or whatever?
Just being able to ping a location on screen is super helpful, otherwise: "Can you open the debug panel please. It's the bug icon in the lower left. No, three icons above that. No you just went past it."
Sharing multiple windows and allowing others to arrange them as the please is also much more productive. Otherwise: "Can we check the app. No not the live app, the local instance"
i loved screen hero but this is probably 10 years too late
Better late than never!
Given CoScreen's very recent demise, we felt this space deserved some love still.
Hopefully you try it out some time, and provide feedback.
Hell yes, thankyou for this! Our team literally been moaning for weeks every time we use Tuple (and Pop! and huddles, and every other tool we tried) that it wasn’t co-screen!
Hi! I'm one of the co-founders of Tuple. What was making you all moan? :)
Ha, sorry! The fact we can't share individual windows. Co-screen was perfect for us.
No worries! Thanks for clarifying :)