5 free Antigravity-powered coding setups for 2026

Google's Antigravity is one of the better free paths to frontier models for coding in 2026. Its free Individual plan comes with weekly rate limits, and through kRouter the models it serves include Gemini 3.1 Pro, Gemini 3.5 Flash, Claude Sonnet 4.6, Claude Opus 4.6 (thinking) and GPT-OSS 120B.

A weekly limit runs out, though. Routed through kRouter and backed by other free services for the days it does, Antigravity becomes a coding setup that keeps working for $0.

What changed in this update (October 2026). Earlier versions of this post said Antigravity came with Google Cloud's $300 of free credits. It does not. The $300 Free Trial is a Google Cloud billing credit; Antigravity's free plan has its own weekly limits and involves no credits at all. The setups below are rebuilt on that, the $300 now appears only where it applies (Vertex AI, in setup 3), and the model names are current.

Here are five setups, ordered from simplest to most capable.

Before you start: the account risk

Antigravity is not licensed for use through third-party tools, and kRouter says so: connecting it shows a risk notice, because Google can restrict or ban the account. kRouter reduces how often that happens; it cannot rule it out.

• The setup call matches Google's own. v0.5.46 fixed the most common trigger in third-party integrations: the loadCodeAssist bootstrap sent string enums ("ideType": "VSCODE") while the OAuth flow sent numeric ones (9), and Google's anti-abuse layer flagged the mismatch. Both now come from the same function.
• A flagged account is left alone. When Google answers "Verify your account", kRouter locks that account for 24 hours, and for longer if it keeps happening, instead of retrying it. The ban post covers how that backoff works.

Use an account you can afford to lose, and do not stack several Google accounts on it.

Setup 1: Antigravity alone (one provider)

The minimum-viable free setup.

1. Install kRouter: npm install -g @sifxprime/krouter && krouter -t
2. Dashboard → Providers → Antigravity → Add Connection, read the risk notice, and sign in with Google
3. Point Claude Code at kRouter (ANTHROPIC_BASE_URL=http://localhost:20128/v1) and use ag/claude-opus-4-6-thinking as the model. The CLI Tools page can write both for you.

Cost: $0.

Catch: the weekly limit. Once it is used up, the account is out until it resets; Google AI Pro and Ultra subscribers get more and refresh more often. kRouter's Quota Tracker page shows what is left and when it resets. When Google names a reset time in its error, kRouter parks that model on the account until then (up to six hours at a time) instead of retrying it every minute.

Setup 2: Antigravity + Kiro fallback

Adds Kiro, whose free plan is 50 credits a month and covers Claude Sonnet 4.5. Now you have two free providers.

Combo:
1. ag/claude-opus-4-6-thinking   # Antigravity
2. kr/claude-sonnet-4.5          # Kiro

When Antigravity's limit runs out, the combo moves to Kiro and the request still succeeds. The list is a preference rather than a fixed order: both providers report remaining quota, so kRouter puts whichever has more left first. Kiro carries the same kind of risk notice as Antigravity.

Setup 3: Antigravity + Vertex AI on the Google Cloud trial

This is where the $300 actually belongs. Google Cloud's Free Trial gives new customers $300 of credit for 90 days. Google's terms say it cannot pay for the Gemini API in AI Studio, or for partner models such as Claude offered as a managed API, so on Vertex AI it is for Google's own models.

1. ag/gemini-pro-agent              # Antigravity, Gemini 3.1 Pro (High)
2. vx/gemini-3.1-pro-preview        # Vertex AI, billed to the trial credit

This is the "I want frontier Gemini all day" setup: Antigravity until its weekly limit, then the same model family on Vertex.

Cost: $0 until the credit or the 90 days run out. You are not charged automatically after that; see the trial steps below.

Setup 4: The all-free stack

Maxes out the free providers:

1. ag/claude-opus-4-6-thinking      # Antigravity (best reasoning)
2. ag/gemini-pro-agent              # Antigravity (Gemini 3.1 Pro)
3. kr/claude-sonnet-4.5             # Kiro free plan
4. oc/space-bunny-free              # OpenCode Free, no account
5. mmf/mimo-auto                    # MiMo Code Free, no account

Five entries, four providers, all free. OpenCode Free and MiMo Code Free need no sign-in at all. OpenCode's free model list rotates, so check it on the provider page, and some of its models collect data during their free period. Both allow one request at a time per connection.

Cost: $0, within each service's limits.

Setup 5: Free first, cheap overflow last

The setup for people who code most of the day and would rather pay a little than stop.

1. ag/claude-opus-4-6-thinking      # Antigravity
2. kr/claude-sonnet-4.5             # Kiro
3. ds/deepseek-v4-flash             # metered overflow

The paid entry goes last on purpose, and kRouter would put it there anyway: entries whose provider reports quota (Antigravity and Kiro) are tried before entries that report none. DeepSeek's pricing page lists deepseek-flash, which still accepts the older deepseek-v4-flash name kRouter uses, at $0.15 per million input tokens off-peak and $0.30 at peak, with output at $0.60 and $1.20 (October 2026).

Cost: whatever the overflow uses, at those rates.

Step-by-step: connecting Antigravity in kRouter

# Install kRouter and run it in the background
npm install -g @sifxprime/krouter
krouter -t

Then open http://localhost:20128/dashboard in a browser:

1. Providers → Antigravity → Add Connection. Read the risk notice, then sign in with your Google account.
2. Press Test on one of its models. The list includes ag/claude-opus-4-6-thinking, ag/gemini-pro-agent and ag/gemini-3-flash-agent.
3. Combos → Create Combo. Add your Antigravity model first and a Kiro or no-account model after it.
4. Point your tool at http://localhost:20128/v1 and use the combo's name as the model. The CLI Tools page writes this for Claude Code, Codex, OpenCode, Cline and others.

From the machine kRouter runs on, no API key is needed unless you set REQUIRE_API_KEY=true. The getting started guide covers keys for other machines.

Using the Google Cloud trial on Vertex AI

1. Sign up for the Google Cloud Free Trial: $300 of credit for 90 days. It is for new customers only, meaning you have never paid for Google Cloud, Google Maps Platform or Firebase, and never had the trial before.
2. Add a card. Google places a temporary authorization hold on it, not a charge.
3. Enable the Vertex AI API in a project and create a service account for it.
4. In kRouter: Providers → Vertex AI → Add Connection, and paste the service account's JSON key.

When the credit or the 90 days run out, Google does not start charging you. The account enters a 30-day grace period, and anything you have not moved to a paid billing account is deleted after it. Do not open extra Google accounts to claim the trial again: it is meant for new customers, and a pile of accounts is the same pattern that gets Google accounts flagged.

What about the Gemini API directly?

An AI Studio key for the Gemini API still has a free tier on Gemini 2.5 Pro, Gemini 2.5 Flash and Gemini 3 Flash Preview; your exact limits are shown in AI Studio. Two catches: Google's pricing page marks free-tier content as used to improve its products, and the Google Cloud trial credit cannot pay for this API.

It is not the same as Antigravity. Antigravity is a separate service with its own weekly limits, and it serves Claude as well as Gemini. The Gemini API serves only Google's models. You can stack both in a combo:

1. ag/gemini-pro-agent
2. gemini/gemini-2.5-pro            # Gemini API free tier

Google also ended Gemini CLI's free tier for personal accounts on June 18, 2026; what still works covers the details.

What it actually costs

• Antigravity, free Individual plan: $0, weekly limits
• Kiro, free plan: $0, 50 credits a month
• OpenCode Free and MiMo Code Free: $0, no account
• Vertex AI on the trial: $0 until the $300 or the 90 days run out
• DeepSeek overflow: per token, at the rates above

How much overflow you pay for depends entirely on how often the free limits run out for you, so this post does not guess at a monthly figure. kRouter's Usage page records the tokens of every request; after a week of normal work you will know your own number.

Install

npm install -g @sifxprime/krouter
krouter -t

Provider setup at /providers/antigravity. Combo guide at /docs/combos. Changelog at /changelog.

Common questions

Does Antigravity come with $300 of free credits?

No. The $300 is Google Cloud's Free Trial credit for new customers, usable on Vertex AI for Google's own models. Antigravity's free Individual plan has weekly rate limits and no credits.

How often does Antigravity's free limit reset?

Weekly on the free Individual plan, according to Google's pricing page. Google AI Pro and Ultra get higher limits that refresh more often. Google has changed these limits more than once, so check the remaining quota on kRouter's Quota Tracker page rather than relying on any article.

Can using Antigravity through kRouter get my account banned?

Yes, it can. Antigravity is not licensed for third-party use, which is why kRouter shows a risk notice before you connect it. kRouter's setup call matches the one Google's own client makes, and it backs off flagged accounts instead of retrying them. That lowers the odds without removing them.

What happens when every entry in the combo is exhausted?

Your tool gets an error. kRouter returns one only after every entry has failed (or at once for errors every model would give, such as a prompt that is too long), so a metered entry at the end, as in setup 5, keeps the work from stopping when the free limits run out.

Related

• Free AI coding assistant: what is actually free
• Antigravity account keeps getting banned? The real fix
• Gemini CLI's free tier is gone: what still works