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

general

# Data Freshness

Data freshness measures how recently scraped data was collected relative to the actual source, a critical metric for price monitoring, news aggregation, and inventory tracking.

Scraped data has a shelf life. A product price scraped 24 hours ago may no longer reflect the current price; a flight fare scraped 6 hours ago may have changed. For use cases where currency matters — competitive pricing, live inventory, news alerts — data freshness is as important as accuracy.

Freshness is typically tracked by recording a `scraped_at` timestamp alongside each record and measuring the lag between when the source updated and when the scraper captured the change. SLA-driven scraping systems define freshness requirements per data type (e.g., prices must be at most 30 minutes old) and configure crawl schedules accordingly.

Event-driven scraping improves freshness compared to fixed schedules: instead of crawling every N hours, the system triggers a re-scrape whenever a change signal is detected (a product's last-modified header changes, a sitemap entry's `<lastmod>` updates, or a webhook fires from the source platform).

### What is Data Freshness?

Data freshness measures how recently scraped data was collected relative to the actual source, a critical metric for price monitoring, news aggregation, and inventory tracking.

### How does AlterLab handle Data Freshness?

Event-driven scraping improves freshness compared to fixed schedules: instead of crawling every N hours, the system triggers a re-scrape whenever a change signal is detected (a product's last-modified header changes, a sitemap entry's `<lastmod>` updates, or a webhook fires from the source platform).

## Related Terms

[Data PipelineA data pipeline is an automated sequence of steps that ingests raw data from a source, transforms it, and delivers it to a destination such as a database, data warehouse, or analytics system.](https://alterlab.io/glossary/data-pipeline)[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 CacheHTTP 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.](https://alterlab.io/glossary/http-cache)[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)[Event-Driven ScrapingEvent-driven scraping triggers scrape jobs in response to external events — webhooks, schedule triggers, or message queue messages — rather than running on a fixed polling interval.](https://alterlab.io/glossary/event-driven-scraping)

## Extract Data Freshness 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)