How to set up the Cloudflare Worker (free, ~2 min):
1. dash.cloudflare.com → Workers & Pages → Create → Create Worker
2. Replace all default code with the script below, click Deploy
3. Copy the worker URL (shown after deploy, ends in .workers.dev) and paste above

Worker script (click to copy) export default { async fetch(request) { if (request.method === 'OPTIONS') { return new Response(null, { headers: { 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Headers': '*', 'Access-Control-Allow-Methods': 'GET,POST,PATCH,DELETE,OPTIONS', }}); } const url = new URL(request.url); const target = 'https://api.notion.com' + url.pathname + url.search; const headers = new Headers(request.headers); headers.delete('origin'); headers.delete('host'); const resp = await fetch(target, { method: request.method, headers, body: request.method !== 'GET' ? request.body : undefined, }); const out = new Response(resp.body, resp); out.headers.set('Access-Control-Allow-Origin', '*'); out.headers.set('Access-Control-Allow-Headers', '*'); return out; } } ↑ Click to copy  ·  Free tier: 100,000 requests/day  ·  The worker only forwards calls to api.notion.com

Security note: Your Notion token travels through the worker, but the code above does not log or store it — you own and control the worker. Tokens are stored only in your browser's localStorage and cleared when you click "Clear Saved".