LLM integration with OpenRouter

OpenRouter is a unified API gateway to hundreds of language models from providers such as OpenAI, Anthropic, Google, and Meta. You use one API key and one billing surface, and swap models by changing a provider/model slug. OpenRouter exposes a Chat Completions -compatible HTTP API. This post shows three Node.js integration paths: the official @openrouter/sdk , the openai package with baseURL , and the Vercel AI SDK with @openrouter/ai-sdk-provider . For deeper patterns on each stack, see the Chat Completions API , OpenAI Responses API (OpenAI direct only), and Vercel AI SDK posts. Prerequisites OpenRouter account API key Credits or billing enabled as needed Node.js version 26 Install packages for the path you use: @openrouter/sdk ( npm i @openrouter/sdk ) openai ( npm i openai ) ai and @openrouter/ai-sdk-provider ( npm i ai @openrouter/ai-sdk-provider ) Configuration Read credentials from the environment in production. Variable Purpose OPENROUTER_API_KEY Bearer token from OpenRouter settings OPENROUTER_MODEL Default model slug, for example openai/gpt-5.5 OPENROUTER_SITE_URL Optional site URL sent as HTTP-Referer for rankings on openrouter.ai OPENROUTER_SITE_TITLE Optional app name sent as X-OpenRouter-Title Model IDs use the provider/model format, for example openai/gpt-5.5 , anthropic/claude-opus-4.8 , or google/gemini-3.1-flash-lite . Browse the full catalog at openrouter.ai/models . The examples below use openai/gpt-5.5 , matching the model in the other LLM posts in this series. Override it with OPENROUTER_MODEL when you want a different model. @openrouter/sdk OpenRouter's official TypeScript SDK is type-safe and generated from the OpenAPI spec. Client setup import { OpenRouter } from ' @openrouter/sdk ' ; const client = new OpenRouter ({ apiKey : process . env . OPENROUTER_API_KEY , httpReferer : process . env . OPENROUTER_SITE_URL , appTitle : process . env . OPENROUTER_SITE_TITLE , }); Basic integration const response = await client . chat . send ({ chatReques