Google Antigravity vs OpenAI Codex: Coding Agents Comparison

Google Antigravity is Google's agentic development platform, announced alongside Gemini 3 in late 2025. Built as a modified VS Code fork, Antigravity combines a traditional AI-powered editor with a Manager View for orchestrating multiple autonomous agents working in parallel across workspaces. Agents can plan, execute, and verify complex tasks across editor, terminal, and browser environments. The platform achieved 76.2% on the SWE-bench Verified benchmark, demonstrating strong code generation capabilities. Antigravity supports Gemini 3 Pro, Deep Think, and Flash models, plus third-party models including Claude, making it flexible for developers who want to use different AI providers. Currently available in preview for personal Gmail accounts on Mac, Windows, and Linux, Antigravity is free during the preview phase but expected to introduce paid tiers. Google AI Pro subscribers ($20/month) and AI Ultra subscribers ($250/month) receive higher rate limits, with rate limits refreshing every 5 hours for Pro users.

OpenAI Codex is a cloud-based autonomous coding agent that runs in a sandboxed environment. Built on GPT-5.3-Codex, it can read codebases, write and edit code across multiple files, run tests, and submit pull requests from natural language task descriptions. Codex operates asynchronously, handling tasks in parallel while developers focus on other work.

The product is available through ChatGPT subscriptions (Plus at $20/month, Pro at $200/month) and via the API using codex-mini-latest at $1.50/1M input tokens and $6.00/1M output tokens. Codex supports both cloud sandbox and local terminal execution modes.

OpenAI was founded in 2015 and is headquartered in San Francisco. The company is valued at approximately $500-730B and is preparing for an IPO that could value it at up to $1 trillion.