Web Crawler – Questions to Ask

Key questions to consider when designing a web crawler, including purpose, scale, handling failures, and data freshness.

What are the 4 main questions to ask when designing a web crawler?

• Who are we designing the system for?

• What is the scale of the system?

• What do we do with failures?

• What time limits and freshness requirements should the data have?

Who are we designing the system for?

The intended users or clients of the crawler.

What is the scale of the system?

Defines how large the crawler must be — number of URLs, capacity, and overall workload.

What do we do with failures?

Define retry strategies, error handling, and durability so the system remains reliable.

Why consider time limits and data freshness?

To ensure data isn’t stale, and the crawler retrieves updated information within acceptable time.