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.
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
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I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.
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SWE with 15+ years of experience building and maintaining web apps and extensive BE infrastructure
Simon A.
I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows.
rayush33
JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems
Anthony Akpan
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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.