```yaml
product: AlterLab
title: "Circuit Breaker — Web Scraping Glossary | AlterLab"
comparison_context: "AlterLab is an alternative to Firecrawl, ScrapingBee, and Bright Data."
source_url: https://alterlab.io/glossary/circuit-breaker
```

infrastructure

# Circuit Breaker

A circuit breaker is a fault-tolerance pattern that stops making requests to a failing endpoint after a threshold of errors, allowing the downstream service time to recover.

Named after its electrical counterpart, a software circuit breaker monitors calls to an external dependency and trips open — stopping all outgoing calls — when the failure rate exceeds a threshold. The breaker enters a half-open state after a configurable timeout, allowing a probe request through. If the probe succeeds, the breaker closes and normal traffic resumes; if it fails, the open state is maintained.

In a scraping context, a circuit breaker prevents a worker pool from hammering a target site that has gone down or started returning consistent errors, which would waste resources and could trigger IP bans. It also protects downstream consumers from cascading failures when a scraping tier is degraded.

Circuit breakers are especially useful in distributed scraping systems where many worker nodes target the same site. Without a breaker, all workers independently retry on the same failing endpoint, amplifying the load exactly when the site is most vulnerable.

### What is Circuit Breaker?

A circuit breaker is a fault-tolerance pattern that stops making requests to a failing endpoint after a threshold of errors, allowing the downstream service time to recover.

### How does AlterLab handle Circuit Breaker?

Circuit breakers are especially useful in distributed scraping systems where many worker nodes target the same site. Without a breaker, all workers independently retry on the same failing endpoint, amplifying the load exactly when the site is most vulnerable.

## Related Terms

[Retry LogicAutomated re-sending of failed requests with backoff strategies, essential for handling transient errors, rate limits, and flaky anti-bot challenges.](https://alterlab.io/glossary/retry-logic)[Exponential BackoffExponential backoff is a retry strategy where the wait time between successive retries increases exponentially, reducing load on rate-limited or temporarily unavailable endpoints.](https://alterlab.io/glossary/exponential-backoff)[Rate LimitingA server-side control that caps the number of requests accepted from a single IP or session within a time window, returning HTTP 429 when exceeded.](https://alterlab.io/glossary/rate-limiting)[Proxy PoolA managed collection of proxy IP addresses used to distribute outbound requests across multiple origins and stay below per-IP rate limits.](https://alterlab.io/glossary/proxy-pool)[Scraping APIA managed web scraping service that abstracts proxy rotation, JavaScript rendering, and automatic website compatibility into a single HTTP endpoint.](https://alterlab.io/glossary/scraping-api)

## Extract Circuit Breaker data from any website

AlterLab returns clean, structured data from any public URL — no scraper infrastructure needed. Start free, no credit card required.

[View API docs](https://alterlab.io/docs/api/rest)

[Back to Glossary](https://alterlab.io/glossary)