Try this addEventListener('fetch', event => { event.respondWith(handleRequest(event.request)) }) async function handleRequest(request) { const url = 'https://api.example.com/endpoint?param1=value1' const response = await fetch(url, { method: 'GET', headers: { 'Authorization': 'Bearer YOUR_API_KEY' } }) const data = await response.json() return new Response(JSON.stringify(data), { status: 200 }) }