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Crawling in Reader means: start at a seed URL, discover links via BFS, and optionally scrape every discovered page. It’s a link-discovery primitive first, with scraping as an opt-in add-on.

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The crawl() primitive

const result = await reader.crawl({
  url: "https://docs.example.com",
  depth: 2,
  maxPages: 50,
});

console.log(`Found ${result.urls.length} pages`);
for (const page of result.urls) {
  console.log(`  ${page.url} - ${page.title}`);
}
This does link discovery only. You get back a list of { url, title, description } entries for every discovered page, but no content.

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Crawl and scrape in one call

Set scrape: true to scrape every discovered page as it’s found: 
const result = await reader.crawl({
  url: "https://docs.example.com",
  depth: 2,
  maxPages: 50,
  scrape: true,
  scrapeConcurrency: 3,
});

console.log(`Discovered: ${result.urls.length}`);
console.log(`Scraped:    ${result.scraped?.batchMetadata.successfulUrls}`);
result.scraped is a full ScrapeResult with markdown for every page.

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How the BFS works

Reader uses breadth-first search starting from the seed URL:
  1. Fetch the seed and extract all links via DOM parsing (linkedom).
  2. Filter the links: same domain, not already visited, matches includePatterns, doesn’t match excludePatterns, not blocked by robots.txt.
  3. Enqueue matching links at depth + 1 if depth < maxDepth.
  4. Rate limit - wait delayMs (default 1000ms) before the next request.
  5. Stop when the queue is empty or maxPages is hit.
The result is deterministic given the same seed and filters. Link order within a page is preserved, so the first maxPages you get are the same on every run.

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Crawl control

OptionDefaultPurpose
depth1Max hops from the seed URL
maxPages20Stop after N pages regardless of depth
delayMs1000Rate limit between requests
includePatterns[]Regex - URL must match at least one
excludePatterns[]Regex - URL must not match any
A common pattern: scope a crawl to a docs subdirectory with includePatterns: 
await reader.crawl({
  url: "https://docs.example.com",
  depth: 5,
  maxPages: 200,
  includePatterns: ["^https://docs\\.example\\.com/api/"],
});

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Same-domain only

Crawling is constrained to the seed’s domain. Reader does not follow external links - that would explode the crawl scope and credits unpredictably. If you need cross-domain discovery, build it yourself by calling crawl() for each domain separately.

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Sticky proxy per crawl

When you configure proxy pools, Reader picks one proxy at the start of a crawl session and uses it for every request in that crawl. This mimics how a real user would browse a site from a single IP - rotating IPs mid-crawl tends to trip anti-bot systems. See Proxy Tiers.

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Where to go next

Website Crawling guide

Patterns for scoping, filtering, and scraping crawls.

CrawlOptions reference

Every option, every default.