Use Modellix LLM with Claude Code

Point Claude Code at the Modellix LLM gateway using the Anthropic-compatible Messages API. Auth and base URL match the Anthropic SDK pattern.

Set Up Claude Code

Get a Modellix API Key

Create a key in the Modellix console. Claude Code maps ANTHROPIC_API_KEY to the Anthropic-style x-api-key header.

Set Environment Variables

export ANTHROPIC_API_KEY="mdlx-xxxxxxxx"
export ANTHROPIC_BASE_URL="https://llm.modellix.ai"

Setting	Value
Base URL	`https://llm.modellix.ai` (without `/v1`)
API key	Modellix API Key (`ANTHROPIC_API_KEY` → `x-api-key`)
Model	`anthropic/...` (for example `anthropic/claude-sonnet-5`). See Models & Pricing.

Do not append /v1 to ANTHROPIC_BASE_URL. Claude Code / the Anthropic SDK append /v1/messages themselves.

If the tool expects Bearer auth, use ANTHROPIC_AUTH_TOKEN instead of ANTHROPIC_API_KEY. Do not set both to different values.

Persist in Settings

Write the same values to ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://llm.modellix.ai",
    "ANTHROPIC_API_KEY": "mdlx-xxxxxxxx"
  }
}

Replace mdlx-xxxxxxxx with your Modellix API key.

Session Headers

Claude Code may send its own session header (for example X-Claude-Code-Session-Id). Modellix also accepts X-Mdlx-Session-Id; if both are present, X-Mdlx-Session-Id wins. See Session header.

Anthropic SDK — Messages examples in Python / TypeScript
Claude Agent SDK — same env vars for the programmable agent harness
Create message — OpenAPI reference
LLM API guide — auth, errors, and rate limits

Get Started

API

Agent

SDK

Framework

IDE

Tool

Use Modellix LLM with Claude Code

Set Up Claude Code

Session Headers

​Set Up Claude Code

​Session Headers

​Related

Set Up Claude Code

Session Headers

Related