Polling Causing Excessive API Calls in Cursor-Built App
Your Cursor-generated application uses client-side polling (setInterval with fetch) to check for updates, but the polling is far too aggressive. Your API is receiving thousands of unnecessary requests per minute, driving up server costs, hitting rate limits, and degrading performance for all users.
Cursor often generates polling as the simplest way to achieve "real-time" updates — a setInterval that calls the API every 1-2 seconds. This works fine with one user in development, but in production with hundreds or thousands of concurrent users, each polling at 1-second intervals, the request volume becomes unsustainable. A seemingly innocent feature like checking for new notifications can generate millions of API calls per day.
The problem compounds because the polling continues even when the browser tab is in the background, the user is idle, or there's no new data to fetch, wasting bandwidth and battery on mobile devices.
Error Messages You Might See
Common Causes
- Polling interval too short — Cursor set a 1-second or 500ms polling interval when 15-30 seconds would suffice for most use cases
- No visibility check — Polling continues at full speed when the browser tab is hidden or the user switches to another app
- No change detection — Every poll fetches the full dataset even when nothing has changed, wasting bandwidth and server resources
- Multiple polling loops running — Component re-renders create duplicate setInterval timers without clearing the previous ones, multiplying request volume
- No backoff on errors — When the server returns errors (500, 429), the client keeps polling at the same rate, making the overload worse
- Polling on every page — The polling code runs globally instead of only on pages where real-time updates are needed
How to Fix It
- Increase polling interval — For most features, 15-30 second intervals are sufficient. Notifications can poll every 60 seconds. Only stock tickers or live gaming truly need sub-second updates
- Pause when tab is hidden — Use the Page Visibility API:
document.addEventListener('visibilitychange', () => { if (document.hidden) clearInterval(poll); else startPolling(); }) - Implement ETag/If-Modified-Since — Return 304 Not Modified when data hasn't changed, saving bandwidth and server processing. Use the
ETagorLast-Modifiedheaders - Clean up intervals on component unmount — In React: return a cleanup function from useEffect. In Vue: clear the interval in onUnmounted. This prevents duplicate polling loops
- Add exponential backoff on errors — When the server returns 429 or 5xx, double the polling interval each time (2s, 4s, 8s, 16s...) and reset to normal when requests succeed
- Switch to push-based updates — Replace polling with SSE, WebSockets, or a service like Supabase Realtime, Firebase, or Pusher for truly real-time features
Real developers can help you.
Sage Fulcher
Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them)
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Get HelpFrequently Asked Questions
How often should I poll my API?
It depends on the use case. Chat messages: 5-10 seconds (or switch to WebSockets). Notifications: 30-60 seconds. Dashboard data: 30 seconds to 5 minutes. Always consider using push-based alternatives (SSE, WebSockets) for true real-time needs.
How do I calculate the API load from polling?
Multiply: (concurrent users) x (polls per minute) x (endpoints polled). Example: 1000 users polling 3 endpoints every 5 seconds = 1000 x 12 x 3 = 36,000 requests per minute. This adds up fast and is why push-based solutions are preferred at scale.