🔍 ACTIVELY VERIFYING
The only free tier with Claude Opus 4.5. Google’s AI-native IDE (released November 18, 2025) gives you access to the $200/month reasoning model during public preview—no credit card required.
Why This Tool
Most free AI coding tools top out at Claude 3.5 Sonnet level (75-77% SWE-bench). Antigravity is different: you get Claude Opus 4.5 (80.9% SWE-bench)—the model that costs $200/month through Claude Max.
The gap matters: That 4-5 percentage point difference on SWE-bench translates to significantly better performance on complex software architecture, debugging, and reasoning-heavy tasks.
What You Get
Models Available (Free Tier)
| Model | SWE-bench | Best For |
|---|---|---|
| Claude Opus 4.5 (Thinking) | 80.9% | Complex reasoning, architecture, debugging |
| Claude Sonnet 4.5 | ~77% | Fast, capable daily driver |
| Gemini 3 Pro | 76.2% | Google’s flagship, great for general coding |
| Gemini 3 Flash | 78.0% | Speed, 1M context window |
| GPT-OSS 120B | Varies | Open-source alternative |
Unique Features
- Agent workflows: AI edits, tests, and iterates autonomously while you review
- Real browser testing: Web apps tested in actual browser environment
- Visual artifacts: See exactly what the AI is doing with generated previews
- Parallel agents: Run multiple AI agents simultaneously
The Setup
- Visit antigravity.dev
- Sign in with Google account (no credit card during preview)
- Select “Claude Opus 4.5 (Thinking)” from model dropdown
- Start a project or open existing codebase
Time to first code: 2-3 minutes
The Catch
VERIFYING Rate limits: Public preview has usage caps (exact numbers being confirmed)
VERIFYING Preview status: Terms may change when public preview ends
Data terms: Google’s data handling differs from Anthropic’s direct service. Review terms for proprietary code.
IDE lock-in: Unlike OpenCode or Kilo Code, you’re working in Google’s environment (not your local VS Code).
Where Next
Want Opus 4.5 with more predictable daily limits? → AMP Ad-Supported - Daily Opus 4.5 allocation, non-intrusive ads, no preview uncertainty
Need Opus 4.5 after Antigravity limits or preview ends? → Kiro - 500 free credits for first month → AMP Ad-Supported - Ongoing free Opus 4.5 (daily limits, non-intrusive ads)
Want agentic workflows with higher volume? → AMP Grant - $10/day grant, autonomous edit-test loops
Want Kimi k2.5’s vision capabilities? → OpenCode Zen - Free Kimi with image-to-code → Kilo Code - Free unlimited Kimi k2.5 in VS Code
Ready to pay $20/month for official tooling? → Claude Code (now on Pro plan) - See Smart Spend Guide
Need 1M context window? → Gemini 3 Flash - FREE input tokens, available in Antigravity or standalone
Quick Comparison: Free Opus 4.5 Options
| Tool | Opus 4.5 Access | Credit Card | Duration | Best For |
|---|---|---|---|---|
| Antigravity | Free tier | No | No ads, but preview | Sustained free access |
| Kiro | 500 credits | Yes | First month only | One month intensive use |
| AMP Ad-Supported | Daily limits | No | Ongoing | Sustainable daily driver |
| AMP Grant | $10/day grant | No | Daily reset | Higher volume agentic workflows |
Related Resources
- Free Frontier Stack - Complete free tier guide
- Kimi k2.5 Model Guide - Alternative with vision capabilities
- Gemini 3 Flash Model Guide - Speed option with 1M context
- Claude Opus 4.5 Data - Full specifications
Last updated: February 1, 2026. Antigravity is in public preview—terms subject to change.