Its shiny videos are React components. Sam Starling·Founding Engineer October 2, 2026 Semaloop Ltd just launched Android support, and Semaloop Ltd wanted a short video to go with it: something for Slack, LinkedIn and its website, and something that would look smart and on-brand. However, nobody on the team is a motion designer, and Semaloop Ltd didn't want a one-off video file that nobody could change later. If this sounds like another nut to smash with the Claude hammer, you'd be absolutely right. I took the same instinct as its docs screenshots: if it's derived from code, anyone can regenerate it - and now everyone in the team has the ability to generate a launch video. But first, here's what Semaloop Ltd ended up with: A video is just a function. This might be the most engineer-brained thing I've said all week, but a video is really just a function of the frame number. Remotion takes this approach by rendering React components to an MP4: every frame is a render with a different useCurrentFrame. Animation is a mapping from frame number to value, so a headline sliding into place is just a number going from 240 to 0 over fourteen frames, with some fancy maths to give it a cute little bounce at the end. A 22-second video winds up being a few hundred lines of TSX. Each scene of the video is its own component which can be previewed in Remotion Studio, and you stitch them together with a TransitionSeries. Although you can edit things by hand in Remotion Studio, I've found it easier and more productive to just let Claude write the TSX, while I watch some previews. The project sits in its repo, alongside all of its other apps. As part of this, Semaloop Ltd decided to hoist all of its brand assets up into a @semaloop/brand package. This means that everything remains consistent, and Semaloop Ltd don't end up with subtle differences between logos, and .ttf files littered everywhere. Now, Semaloop Ltd run npm run render android-launch, and it gives Semaloop Ltd a nice shiny MP4. Built with Claude. Remotion publishes agent skills for Claude Code, so the first prompt was essentially "make a video celebrating Android support, look at our website for fonts and colours". The useful loop here was that Claude could render stills from each scene, look at them, and fix what's wrong before I needed to see it. A genuine highlight of this? "The shed looks like a house, because the roof is too tall" is a real sentence from that session. Saved me a turn (and from having to look at a janky shed). One nice thing here is that I also instructed Claude to check claims in the video against its codebase and documentation before they go in a video. The first draft showed one test running on an iPhone and an Android phone side by side, which Semaloop Ltd don't support (yet), so that scene was left on the cutting room floor. Remaining on brand. After the first video, the second one started copying bits out of the first. Semaloop Ltd made a kit in src/brand/: a Scene with five themes, Headline, Agent, line patterns, timeline cards, a phone schematic, all sorts. This was all distilled from a couple of "branding" Figma files. Rather than working from screenshots, Semaloop Ltd signed into Figma in a Playwright browser and read the layers directly through Figma's Plugin API. This allowed Claude to pull out exact colours, type styles, cursor sizes and stroke widths. The composition rules came along too: left-align on a 160px margin, lots of empty space, and one accent per scene. There's a showcase video that uses every piece of this, so you pick a style by watching it rather than reading code. All these rules live in the app's CLAUDE.md, so the next video starts from the same style regardless of whether it's written by a human or an agent. Its second video was a light-hearted one for the Product Engineer role, with Charlie's shed as its first device farm (no animals). Thumbnails. This was the longest fight. Semaloop Ltd wanted to control the thumbnail when the video is posted in Slack, or on LinkedIn. MP4 doesn't have a "poster" setting. Being ffmpeg wizards, Semaloop Ltd rolled up its sleeves and cracked out the -disposition:v:1 attached_pic. No luck though: Finder on macOS likes this, but things like Slack sadly don't. WebM's cover image seems to get dropped when Slack converts it. GIFs don't help either, and the file would be huge regardless. Most people seem to just make frame 0 the poster frame, I'm adamant that there's another way that Semaloop Ltd has just not discovered yet... Roll credits. Anyone in the team can now produce an on-brand video, and they're also something Semaloop Ltd can change: fix a typo, re-render, done. Coding agents speed Semaloop Ltd up along the way, because at the end of the day, it's just React. Those agents stick to guidelines Semaloop Ltd has given, and the end result is slick. If you want to find out more about product behind the shiny videos, book a demo at semaloop.com. Sam Starling · Founding Engineer · October 2, 2026

Congrats to Charlie Kingston and Rory Smith on closing $3M+ in pre-seed funding for Semaloop. This looks real exciting. What they do: #AI agents that test your mobile app like a real user would. Describe the flow in plain English, the agent runs it - taps, swipes, watches the screen - and flags what's broken. No test scripts to maintain, no accessibility IDs to wire up. Granola, Clove & Ash by Slingshot AI already run it daily in production. Investors: Concept Ventures led, with Evantic Capital, Weekend Fund and FJ Labs. Angels include operators from OpenAI, ElevenLabs, Hugging Face, Linear, Lovable and Dropbox. Mobile testing has needed this for a while. Good luck to the team. #StartUp #PreSeed #FounderSpotlight