```yaml
product: AlterLab
title: "HTTP Cache — Web Scraping Glossary | AlterLab"
comparison_context: "AlterLab is an alternative to Firecrawl, ScrapingBee, and Bright Data."
source_url: https://alterlab.io/glossary/http-cache
```

protocol

# HTTP Cache

HTTP caching stores copies of responses at the client or an intermediate proxy, allowing subsequent requests for the same resource to be served without a full server round-trip.

HTTP defines a rich set of caching headers that control how responses are stored and reused. `Cache-Control: max-age=3600` tells clients to use a cached copy for up to one hour. `ETag` and `Last-Modified` headers enable conditional requests: the client sends `If-None-Match` or `If-Modified-Since` headers, and the server responds with 304 Not Modified (no body, just reconfirm the cache is valid) if the content has not changed.

For scrapers, HTTP caching is a double-edged tool. On one hand, respecting cache headers reduces unnecessary requests to the target server (polite and efficient). On the other hand, scraping platforms should validate cache freshness before returning cached data, especially for price monitoring or news aggregation where staleness matters.

Some anti-bot systems manipulate cache headers to force scrapers to make more requests (disabling caching) or to detect scrapers that ignore cache control (never requesting fresh content). Understanding cache semantics helps scrapers behave like real browsers.

### What is HTTP Cache?

HTTP caching stores copies of responses at the client or an intermediate proxy, allowing subsequent requests for the same resource to be served without a full server round-trip.

### How does AlterLab handle HTTP Cache?

Some anti-bot systems manipulate cache headers to force scrapers to make more requests (disabling caching) or to detect scrapers that ignore cache control (never requesting fresh content). Understanding cache semantics helps scrapers behave like real browsers.

## Examples

```
# Check if response is fresh or from cache
import requests

response = requests.get("https://example.com/prices")
cache_control = response.headers.get("Cache-Control", "")
age = response.headers.get("Age", "0")  # seconds since cached
etag = response.headers.get("ETag")
print(f"Cache-Control: {cache_control}, Age: {age}s, ETag: {etag}")
```

## Related Terms

[CachingStoring copies of web responses to serve repeat requests faster, which can cause scrapers to receive stale data instead of live content.](https://alterlab.io/glossary/caching)[HTTP HeadersKey-value metadata fields sent with HTTP requests and responses that communicate authentication, content type, caching, and other directives.](https://alterlab.io/glossary/http-headers)[HTTPHTTP (HyperText Transfer Protocol) is the application-layer protocol used by web browsers and scrapers to request and receive resources from web servers.](https://alterlab.io/glossary/http)[Content Delivery Network (CDN)A distributed network of servers that delivers web content from locations geographically close to the user, often where anti-bot protection is deployed.](https://alterlab.io/glossary/content-delivery-network)[ETL (Extract, Transform, Load)ETL is a data integration pattern where raw data is Extracted from a source, Transformed into the desired format, and Loaded into a destination system.](https://alterlab.io/glossary/etl)

## Extract HTTP Cache 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)