Custom client integration

Overview

Antigravity Manager supports any client that implements OpenAI, Anthropic, or Gemini API protocols. This guide covers how to integrate custom clients, applications, and scripts.

Supported protocols

Antigravity provides three API protocol formats:

OpenAI

Endpoint: /v1/chat/completionsUse for: Most third-party AI applicationsCompatibility: 99% of AI tools

Anthropic

Endpoint: /v1/messagesUse for: Claude-native clientsFeatures: Full thinking mode support

Gemini

Endpoint: /v1/models/*:generateContentUse for: Google AI SDK clientsFeatures: Native Gemini protocol

Basic configuration

All custom clients need three pieces of information:

Base URL

Point your client to Antigravity’s proxy:

http://127.0.0.1:8045

For OpenAI-compatible clients, append /v1:

http://127.0.0.1:8045/v1

API Key

Use any value if authentication is disabled:

sk-antigravity

Or use your configured API key if authentication is enabled.

Model name

Choose from available models:

gemini-3-flash - Fast, cost-effective
gemini-3-pro-high - High quality
claude-sonnet-4-6 - Balanced
claude-sonnet-4-6-thinking - Extended reasoning

OpenAI-compatible clients

Configuration template

Most OpenAI-compatible clients accept these settings:

{
  "baseURL": "http://127.0.0.1:8045/v1",
  "apiKey": "sk-antigravity",
  "defaultModel": "gemini-3-flash"
}

cURL examples

Basic chat
Streaming
Image generation

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gemini-3-flash",
    "messages": [
      {"role": "user", "content": "Hello!"}
    ]
  }'

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gemini-3-flash",
    "messages": [
      {"role": "user", "content": "Write a story"}
    ],
    "stream": true
  }'

curl -X POST http://127.0.0.1:8045/v1/images/generations \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gemini-3-pro-image",
    "prompt": "A beautiful sunset",
    "size": "1024x1024",
    "quality": "hd"
  }'

Anthropic/Claude clients

Configuration

{
  "baseURL": "http://127.0.0.1:8045",
  "apiKey": "sk-antigravity"
}

cURL example

curl -X POST http://127.0.0.1:8045/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: sk-antigravity" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 1024,
    "messages": [
      {"role": "user", "content": "Hello!"}
    ]
  }'

Gemini clients

Configuration

{
  "baseURL": "http://127.0.0.1:8045",
  "apiKey": "sk-antigravity"
}

cURL example

curl -X POST "http://127.0.0.1:8045/v1/models/gemini-3-flash:generateContent" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "contents": [{
      "parts": [{"text": "Hello!"}],
      "role": "user"
    }]
  }'

Popular applications

LangChain

from langchain_openai import ChatOpenAI

llm = ChatOpenAI(
    base_url="http://127.0.0.1:8045/v1",
    api_key="sk-antigravity",
    model="gemini-3-flash"
)

response = llm.invoke("Hello!")
print(response.content)

LlamaIndex

from llama_index.llms.openai import OpenAI

llm = OpenAI(
    api_key="sk-antigravity",
    api_base="http://127.0.0.1:8045/v1",
    model="gemini-3-flash"
)

response = llm.complete("Hello!")
print(response)

Continue.dev

// config.json
{
  "models": [
    {
      "title": "Antigravity Gemini",
      "provider": "openai",
      "model": "gemini-3-flash",
      "apiBase": "http://127.0.0.1:8045/v1",
      "apiKey": "sk-antigravity"
    }
  ]
}

Cline (formerly Claude Dev)

{
  "apiProvider": "anthropic",
  "apiKey": "sk-antigravity",
  "apiUrl": "http://127.0.0.1:8045",
  "modelId": "claude-sonnet-4-6"
}

Authentication modes

Antigravity supports different authentication configurations:

Off (Development)
Auto (Recommended)
Strict

No authentication required:

curl http://127.0.0.1:8045/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{...}'

Only use this for local development. Not recommended for production.

Automatically enables auth for LAN access:

# Local (no auth needed)
curl http://127.0.0.1:8045/...

# Remote (auth required)
curl http://192.168.1.100:8045/... \
  -H "Authorization: Bearer sk-your-key"

Always requires authentication:

curl http://127.0.0.1:8045/v1/chat/completions \
  -H "Authorization: Bearer sk-your-key" \
  -d '{...}'

Advanced features

Model routing

Map client model names to Antigravity models:

// Antigravity model routing config
{
  "mappings": [
    {
      "from": "gpt-4",
      "to": "gemini-3-pro-high"
    },
    {
      "from": "gpt-3.5-turbo",
      "to": "gemini-3-flash"
    }
  ]
}

Now clients can use familiar names:

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gpt-4",
    "messages": [...]
  }'
# Automatically routes to gemini-3-pro-high

Session binding

For multi-turn conversations, enable session binding:

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Authorization: Bearer sk-antigravity" \
  -H "X-Session-ID: my-conversation-123" \
  -d '{...}'

Antigravity will use the same account for all requests with this session ID.

Custom headers

Pass custom headers for advanced control:

X-Preferred-Account

string

Use a specific account by email

X-Model-Tier

string

Prefer accounts of a specific tier (ultra, pro, free)

X-Session-ID

string

Enable sticky sessions for multi-turn conversations

Testing your integration

Test connectivity

curl http://127.0.0.1:8045/health

Expected: {"status": "ok"}

Test basic request

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gemini-3-flash",
    "messages": [
      {"role": "user", "content": "Say hello"}
    ]
  }'

Test streaming

curl -X POST http://127.0.0.1:8045/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-antigravity" \
  -d '{
    "model": "gemini-3-flash",
    "messages": [{"role": "user", "content": "Count to 10"}],
    "stream": true
  }'

Monitor in Antigravity

Check the Monitor tab in Antigravity to see request logs and account rotation.

Troubleshooting

404 Not Found

Common causes:

Wrong base URL (forgot /v1 for OpenAI protocol)
Invalid model name
Incorrect endpoint path

Solution: Verify endpoint matches protocol format

401 Unauthorized

Common causes:

Authentication enabled but no key provided
Wrong API key
Missing Authorization header

Solution: Check auth mode in Antigravity settings

429 Rate Limited

Common causes:

All accounts exhausted
Quota protection enabled

Solution: Check dashboard, refresh quotas, add more accounts

Connection refused

Common causes:

Antigravity proxy not running
Wrong port
Firewall blocking connection

Solution: Verify proxy is running and accessible

Best practices

Start simple: Test with cURL before integrating
Handle errors: Implement retry logic and error handling
Use streaming: For better UX with long responses
Monitor usage: Check Antigravity dashboard regularly
Configure routing: Map model names for easier migration
Enable session binding: For multi-turn conversations
Test thoroughly: Verify all features work as expected

Getting Started

Core Features

Integration Guides

Configuration

Deployment

Troubleshooting

Overview

Supported protocols

OpenAI

Anthropic

Gemini

Basic configuration

OpenAI-compatible clients

Configuration template

cURL examples

Anthropic/Claude clients

Configuration

cURL example

Gemini clients

Configuration

cURL example

Popular applications

LangChain

LlamaIndex

Continue.dev

Cline (formerly Claude Dev)

Authentication modes

Advanced features

Model routing

Session binding

Custom headers

Testing your integration

Troubleshooting

Best practices

Build docs developers (and LLMs) love

Getting Started

Core Features

Integration Guides

Configuration

Deployment

Troubleshooting

​Overview

​Supported protocols

OpenAI

Anthropic

Gemini

​Basic configuration

​OpenAI-compatible clients

​Configuration template

​cURL examples

​Anthropic/Claude clients

​Configuration

​cURL example

​Gemini clients

​Configuration

​cURL example

​Popular applications

​LangChain

​LlamaIndex

​Continue.dev

​Cline (formerly Claude Dev)

​Authentication modes

​Advanced features

​Model routing

​Session binding

​Custom headers

​Testing your integration

​Troubleshooting

​Best practices

​Related documentation

Build docs developers (and LLMs) love

Overview

Supported protocols

Basic configuration

OpenAI-compatible clients

Configuration template

cURL examples

Anthropic/Claude clients

Configuration

cURL example

Gemini clients

Configuration

cURL example

Popular applications

LangChain

LlamaIndex

Continue.dev

Cline (formerly Claude Dev)

Authentication modes

Advanced features

Model routing

Session binding

Custom headers

Testing your integration

Troubleshooting

Best practices

Related documentation