Add Model Fallback to an OpenAI-Compatible Node.js App

A single model can be unavailable, rate-limited, or temporarily slow. If your application already uses an OpenAI-compatible API, a simple fallback can make testing more resilient without introducing another SDK. This tutorial uses Node.js and the official OpenAI JavaScript package. It tries one model first and switches to a second model only when the first request fails. 1. Install the SDK npm install openai 2. Store the API key outside your code On macOS or Linux: export JINZEAI_API_KEY = "your_api_key_here" On PowerShell: $ env : JINZEAI_API_KEY = "your_api_key_here" Never commit a real API key. Rotate it immediately if it appears in a public repository, screenshot, or support message. 3. Create an OpenAI-compatible client import OpenAI from " openai " ; const client = new OpenAI ({ baseURL : " https://jinzeai.cc/v1 " , apiKey : process . env . JINZEAI_API_KEY , }); 4. Add a small fallback function const models = [ " deepseek-chat " , " qwen-flash " ]; async function completeWithFallback ( messages ) { let lastError ; for ( const model of models ) { try { const response = await client . chat . completions . create ({ model , messages , }); return { model , text : response . choices [ 0 ]. message . content , }; } catch ( error ) { lastError = error ; console . warn ( ` ${ model } failed: ${ error . status ?? " unknown status " } ` ); } } throw lastError ; } const result = await completeWithFallback ([ { role : " user " , content : " Explain model fallback in one sentence. " , }, ]); console . log ( `Model: ${ result . model } ` ); console . log ( result . text ); 5. Decide which errors should trigger fallback The minimal example retries on every error so the control flow is easy to see. A production application should be more selective. Fallback may be reasonable for: rate limits; upstream server errors; temporary timeouts; a model that is unavailable to the current account. Do not silently retry authentication errors. An HTTP 401 usually means the key is missing,