Polling

Polling is the practice of repeatedly sending requests to an API or service to check if something has changed. Instead of waiting to be notified (push), your application asks "anything new?" at regular intervals (pull). It's simple to implement but can be wasteful — most responses will be "no, nothing changed."

Polling vs webhooks

Aspect	Polling	Webhooks
Direction	You request data (pull)	Service sends data to you (push)
Latency	Up to one poll interval	Near real-time
Wasted requests	High — most return "no change"	Zero — only fires on events
Implementation	Simple — just a scheduled HTTP call	Requires a public endpoint
Reliability	You control the timing	Depends on sender's delivery
API quota usage	Constant, regardless of activity	Proportional to events

When polling is the right choice

• No webhook support — the API you're integrating with doesn't offer webhooks
• No public endpoint — you can't expose a URL for the service to call (firewalled environments, local development)
• Batch processing — you want to collect changes in bulk every N minutes rather than processing each event individually
• Webhook backup — poll as a safety net in case a webhook delivery fails
• Simple integration — polling requires no infrastructure beyond a scheduled HTTP call

When to prefer webhooks

• Real-time requirements — you need to react within seconds
• High-volume APIs — polling every minute burns API quota even when nothing changes
• Rate-limited APIs — rate limits constrain how often you can poll

Implementing efficient polling

Use timestamps or cursors

Don't re-fetch the entire dataset on every poll. Pass a since timestamp or cursor from your last successful poll so the API only returns new or changed records.

Respect rate limits

Check the API's rate limit headers and adjust your poll interval accordingly. If the API allows 100 requests per minute, polling every second will quickly exhaust your quota.

Handle "no change" gracefully

APIs may return 304 Not Modified or an empty result set. Your code should handle this as a normal case, not an error.

Use conditional requests

If the API supports it, send If-Modified-Since or If-None-Match (ETag) headers. The API returns 304 with no body if nothing changed, saving bandwidth and processing.

Polling with a cron scheduler

A cron expression is the natural way to define poll intervals. Set up a cron job that calls your polling endpoint every 5 or 15 minutes. With an external scheduler like Recuro, you also get execution logs, retry policies, and failure alerts — so you know when your polling job stops working.

FAQ

What is polling in software?

Polling is repeatedly asking a server if something has changed by sending periodic HTTP requests. It's the opposite of a push-based approach like webhooks.

How often should I poll?

It depends on your latency requirements and the API's rate limits. Every 1 minute for near-real-time needs, every 5–15 minutes for typical data sync, or every hour for batch-style processing.

Is polling bad practice?

Not inherently. Polling is simpler than webhooks and works when webhooks aren't available. The key is to poll efficiently: use timestamps, respect rate limits, and choose an appropriate interval.

Polling is a pull-based alternative to webhooks (push-based) and event-driven architecture. It runs on a cron schedule and must respect rate limits. Each poll is essentially a background job — schedule it with a retry policy so transient failures don't cause missed polls. When the API you're polling supports them, switching to webhook events eliminates wasted requests entirely.