LLM Gateway

APIXO is a drop-in LLM API gateway. If your code or app already supports Claude, OpenAI, or Gemini API formats, you usually only need to change the base URL, API key, and model id.

Fastest setup

Create an API key in the APIXO dashboard.
Store it as APIXO_API_KEY.
Use the compatible API format your app already supports.
Change the model value when you want to switch models.

export APIXO_API_KEY="your_apixo_api_key"

Choose your API format

If your app supports	Use this Base URL	API key setting	Model example
Claude / Anthropic	`https://llm.apixo.ai`	`APIXO_API_KEY`	`claude-sonnet-4-6`
OpenAI Responses	`https://llm.apixo.ai/v1`	`APIXO_API_KEY`	`gpt-5.4`
Gemini	`https://llm.apixo.ai`	`APIXO_API_KEY`	`gemini-3.1-pro-preview`

APIXO keeps the official request and response formats. Do not rewrite your payload unless you are also changing provider format.

Minimal requests

Claude
OpenAI
Gemini

curl -X POST "https://llm.apixo.ai/v1/messages" \
  -H "x-api-key: $APIXO_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 256,
    "messages": [
      {"role": "user", "content": "Say hello in one sentence."}
    ]
  }'

curl -X POST "https://llm.apixo.ai/v1/responses" \
  -H "Authorization: Bearer $APIXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.4",
    "input": "Say hello in one sentence."
  }'

curl -X POST "https://llm.apixo.ai/v1beta/models/gemini-3.1-pro-preview:generateContent" \
  -H "x-goog-api-key: $APIXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [{"text": "Say hello in one sentence."}]
      }
    ]
  }'

Switch models

To switch models, keep the same API format and change only the model id.

API format	Where to change the model
Claude	Request body `model`
OpenAI Responses	Request body `model`
Gemini	URL path `/v1beta/models/{model}:generateContent`

See Supported Models for the current model ids.

Next steps

Use official SDKs

Configure Claude, OpenAI, and Gemini compatible SDK clients.

Configure third-party apps

Use APIXO in apps that accept a custom provider endpoint.

Supported models

Copy a model id for Claude, OpenAI, or Gemini compatible requests.

Errors and retry

Troubleshoot authentication, unsupported models, and upstream failures.

Getting Started

Compatible APIs

Reference

Fastest setup

Choose your API format

Minimal requests

Switch models

Next steps

Use official SDKs

Configure third-party apps

Supported models

Errors and retry

​Fastest setup

​Choose your API format

​Minimal requests

​Switch models

​Next steps

Use official SDKs

Configure third-party apps

Supported models

Errors and retry

Fastest setup

Choose your API format

Minimal requests

Switch models

Next steps