OpenGravity – A zero-install, BYOK vanilla JS clone of Antigravity
Hi. I’m a high school student studying for my GCSEs. I was using Google Antigravity heavily for my side projects, but I kept hitting the usage limits, and getting random "agent terminated" errors. So I decided to try build my own version of the IDE. I love the UI, so I copied it as accurately as possible, and then hooked up some logic into it, including the INCREDIBLY finicky webcontainer api. I tried to keep it super lightweight, no build steps, or dependencies, and now that its open source, I'm hoping people can build things on top of it that arent possible with closed source tools, like…
In plain words
OpenGravity is a lightweight, open-source IDE built in vanilla JavaScript that replicates Google's Antigravity interface without installation or dependencies. Created by a high school student to overcome usage limits and error issues, it provides an alternative for developers building AI agent projects. The tool uses the WebContainer API and offers a foundation for custom workflows and extensions not possible with closed-source alternatives, making it accessible for both learning and development purposes.
written from the facts on this page · September 2026
From the sources
In the maker’s words, at launch
Hi. I’m a high school student studying for my GCSEs. I was using Google Antigravity heavily for my side projects, but I kept hitting the usage limits, and getting random "agent terminated" errors. So I decided to try build my own version of the IDE. I love the UI, so I copied it as accurately as possible, and then hooked up some logic into it, including the INCREDIBLY finicky webcontainer api. I tried to keep it super lightweight, no build steps, or dependencies, and now that its open source, I'm hoping people can build things on top of it that arent possible with closed source tools, like complex custom agent workflows. Some screenshots: - https://github.com/ab-613/OpenGravity/blob/main/examples/scr... - https://github.com/ab-613/OpenGravity/blob/main/examples/htm... What it's made from: - Pure Vanilla JS: no react, vue, or build step. Built entirely in plain HTML/CSS/JS to keep it super lightweight. - WebContainer API and xterm.js: Instead of faking a terminal, I (after much pain) hooked up the WebContainer API so the AI agent has a real, in browser linux environment to run shell commands, install dependencies, and edit local files. - BYOK (Bring Your Own Key): API key ALWAYS stays in localStorage. Whats currently happening: - It works, but it's an alpha. The AI can proactively start projects going properly and edit files, but because I built this over a few days before my exams, a lot of the UI dropdowns and buttons are currently just hardcoded placeholders. - I’m open sourcing it early because I think the foundation of a Vanilla JS + WebContainer IDE is really strong, and I'd love to see where the community takes it while I'm doing my exams. - Live demo: https://opengravity.pages.dev (Zoom out to 80% if not full screen. It will prompt for a gemini api key on load). Start by uploading a folder, then you can fiddle with the terminal and agent, and see how it goes! Would love to hear feedback on the code, the WebContainer integration, or how to improve the agent loop!
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