alt Hacker NewsShow HN: 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 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!
Comments
Is there any other editor that comes close to JetBrain's Git integration? All I see is forks of forks of VSCode, and I'm wondering what the incremental gain of yet another does-the-basic-text-editing editors we need. This is in no way directed at OP, but it seems like a lot of wheels spinning around the world and surprisingly little progress at the Pareto limit.
Nice project. For the agent loop, the two UX pieces I'd make impossible to miss are: 1) a plan/checkpoint before file writes, and 2) a diff/revert view after each tool run.
WebContainer is great for "run it and see", but state can get fuzzy fast. The more the UI shows exactly what changed and why, the safer it feels to trust the agent.
GCSEs, I was disallowed from taking my IT GCSE because I "hacked the school".
Cool, seems a bit niche? Antigravity is ok but not so ok as to want to clone it, might just be me.
I wish this could work with your monthly subscription where you get a flat quota in Antigravity with a free account / $20.
edit:
Is this not built out of VSCode? Isn't Antigravity based on VSCode? VSCodium has a Web build https://github.com/VSCodium/vscodium
UI wise it might be good to make it clearer you don't need to put in an API key to try it.
I personally don't like antigravity very much, because in some hallucinations the AI ends up removing important parts of your code. It doesn't have a continuous learning engine for your project; if you switch users you may experience problems due to loss of context when reloading the session.
Edit: A mod suggested I add in how I actually use this! Right now, its honestly just a massive side project that serves as a fun distraction from my GCSE revision. But I mainly use it to test out quick HTML/CSS/JS ideas in my browser when I get an idea, without needing to boot up a full dev environment or worry about rate limits.
Should've named it ZeroGravity to stay true to its design goals.
But... does it clone Antigravity's commitment to storing keys at well known locations on disk in plain text?
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Wow, I can't believe this hit the front page! Its past midnight here in the UK and I have to be up early for GCSEs, so I'm heading to sleep. I'll read and reply to all your comments and questions first thing in the morning! Thank you all so much for the amazing feedback and stars so far.