We couldn't buy fast video, so we built it
Rend started as plumbing for Cap, our open source screen recorder. The story is short. We needed video that played the instant someone opened a link, nothing on the market did it the way we wanted, and so we wrote our own.
The video we kept losing
Cap is a screen recorder. You hit record, capture something on your screen, and send a link. The whole thing rests on one moment: a teammate clicks that link, and the video is already playing. If it stalls, the moment is gone and so is their attention.
For a while we stitched that moment together from the usual parts, and it mostly held up. The slow case was always the same one: the very first time anyone opened a clip. Nothing was cached, the bytes were sitting in some distant bucket, and the player just spun while the round trips stacked up. That first frame is the one that matters most, and it was the one we kept losing.
So we went shopping. Minute-billed platforms, per-gigabyte CDNs, the lot. They were good at the easy case, a video that has already been watched a thousand times and cached everywhere. None of them were built for the cold open, the first request to a brand new recording, which for a screen recorder is most of the traffic.
In the end we built it ourselves. Rend generates the playback artifacts players need during processing and serves them through Rend-controlled URLs. The first request can hand back real HLS media without exposing private storage links, and Cap started feeling instant.
Then it occurred to us that every developer shipping video runs into the same wall, so we opened it up. Rend is its own product now, running on the exact code that serves Cap.
Cap runs entirely on Rend.
The same code we run
We did not keep a faster version for ourselves. Rend is open source, and the code you self-host is what we run for Cap.
The server is AGPL and the player and SDKs are MIT. You can read every line, run it on your own machines for free, or let us run the edge for you. We do not charge for the software. We charge for the network that makes it fast.
A small team that hates buffering
We are the team behind Cap. We care, maybe a little too much, about video that loads the second you ask for it. Rend is the infrastructure we built to get there, and we run it in the open so you can hold us to it.
Frequently asked questions
A few questions we get about who is behind Rend.
- Who builds Rend?
- The team behind Cap, the open source screen recorder. Rend is the video infrastructure we built for ourselves, then opened up for other developers.
- What is Cap?
- Cap is an open source screen recorder used by a lot of people. Every recording has to be stored and play back the moment someone opens a share link, which is exactly the problem Rend solves.
- Does Cap really run on Rend?
- Yes. Cap runs entirely on Rend. The footage you share from Cap is served through the same infrastructure we offer everyone else.
- Is Rend a separate product from Cap?
- Yes. Rend is standalone video infrastructure that any developer can use or self-host. It just happens to be the stack that powers Cap.