Message formats (TypeScript)

A basic chat message has a role and content. Send system, user, and assistant messages in conversation order. Tool and multimodal formats depend on the selected model.

This guide uses the official OpenAI client with TheRouter; it is not a TheRouter-owned SDK. The therouter and @therouter/sdk packages previously named here are not currently published in the public package registries.

npm install openai

import OpenAI from "openai";

const client = new OpenAI({ apiKey: process.env.THEROUTER_API_KEY, baseURL: "https://api.therouter.ai/v1" });
const completion = await client.chat.completions.create({
  model: "openai/gpt-4o-mini",
  messages: [{ role: "user", content: "Hello!" }],
  max_tokens: 32,
});
console.log(completion.choices[0]?.message.content);