What Is API Polling and Why It Matters

API polling is the practice of repeatedly querying an API endpoint at regular intervals to detect changes. It is the most universal method for getting updates from APIs that do not support webhooks or server-sent events natively.

How API Polling Works

At its core, polling follows a simple loop:

1. Send a request to the API endpoint
2. Compare the response to the previous response
3. If changes are detected, trigger downstream actions
4. Wait for a defined interval
5. Repeat

// Basic polling loop
async function poll(url, interval = 30000) {
  let previous = null;

  while (true) {
    const response = await fetch(url);
    const data = await response.json();

    if (JSON.stringify(data) !== JSON.stringify(previous)) {
      console.log('Change detected:', data);
      // Trigger your event handler
    }

    previous = data;
    await new Promise((r) => setTimeout(r, interval));
  }
}

This approach works but has significant limitations at scale: rate limiting, wasted requests, and no field-level granularity.

When Polling Is the Right Choice

Polling is the correct strategy when:

• The API has no webhook support: most legacy and enterprise APIs fall into this category
• You need guaranteed delivery: polling never misses events since you control the schedule
• You want simplicity: no public endpoints, no SSL certificates, no webhook signature verification
• Rate limits are generous: APIs with high rate limits make polling cost-effective

Intelligent Polling with RocketHooks

RocketHooks transforms basic polling into an intelligent change detection engine. Instead of comparing entire JSON payloads, it monitors specific fields using JSONPath expressions:

# Monitor only the status and assignee fields
monitor:
  - $.data.status
  - $.data.assignee.email
  - $.data.updated_at

This means fewer false positives, lower bandwidth usage, and precise event triggers that match your business logic.

Polling vs Webhooks

The best approach often combines both: use webhooks where available, and intelligent polling as a universal fallback for APIs that lack native event support.

FAQ

What is the ideal polling interval?

The ideal interval depends on your API rate limits and freshness requirements. Most use cases work well with 30-60 second intervals. RocketHooks automatically calculates optimal intervals based on rate limit headers.

Does polling scale to thousands of endpoints?

Yes, with proper architecture. RocketHooks uses distributed scheduling across serverless functions to poll thousands of endpoints concurrently without resource bottlenecks.

Can I poll authenticated APIs?

Absolutely. RocketHooks supports OAuth 2.0, API keys, Bearer tokens, and custom header authentication for polling any protected endpoint.