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Protect your Sim API key when making requests from client-side apps by using a Cloudflare Worker as a proxy. This worker receives requests from your app, securely adds your SIM_API_KEY on the server, and then forwards the requests to the Sim API endpoints. When to use a proxy:
  • Your app makes Sim API calls from the browser (React, Next.js client components, etc.)
  • You need to avoid exposing your API key in client-side JavaScript
  • You need to handle CORS for browser-based requests
When you don’t need a proxy:
  • Server-to-server calls (Node.js backends, Python scripts, etc.) can call the Sim API directly
We provide a one-click-deploy Cloudflare Worker to simplify this setup. Find detailed instructions in our GitHub repo:

Sim API Proxy on GitHub

One-click deployment and comprehensive setup instructions for the Cloudflare Worker proxy.