Frontier · framework

Use Claude Sonnet 4 with LlamaIndex

Updated 2026-05-21 · By XALEN

How to use Claude Sonnet 4 (Frontier, ~500B) with LlamaIndex. Install, authenticate, and make your first API call in minutes. Working code example included.

Model

Claude Sonnet 4

~500B · 200K context · $0.03 input

Framework

LlamaIndex

framework · pip install llama-index-llms-openai-like

1. Install

pip install llama-index-llms-openai-like

2. Code

from llama_index.llms.openai_like import OpenAILike

llm = OpenAILike(
    model="claude-sonnet-4",
    api_key="xln_test_YOUR_KEY",
    api_base="https://api.xalen.io/v1"
)

response = llm.complete("Explain Claude Sonnet 4")
print(response.text)

Claude Sonnet 4 with Other Frameworks

Python JavaScript React Next.js Flask FastAPI Django Express.js

Other Models with LlamaIndex

Vedika Standard Vedika Fast Vedika Pro Ultra Vedika Vision Vedika Code Vedika Astro Agent

200+ models. One API. Works with any framework.

Get API Key

Last updated: 2026-05-21