The function of web crawlers in search engine optimization (SEO) involves systematically scanning web pages and indexing their content for search engines. These automated bots analyze websites' structures, keywords, and links to determine their relevance and authority. Web crawlers collect data that feeds into search algorithms, influencing how pages rank in search results. Optimizing a website for crawlers, through effective use of meta tags, sitemaps, and quality content, is crucial for improving visibility and attracting organic traffic.