Tumblr actively blocks known AI web crawlers — automated programs that AI companies use to collect text and images from across the internet for model training — from accessing its content. This is managed through a technical configuration file called robots.txt that instructs crawlers which pages they may not visit. Tumblr's own licensing deals represent a notable exception to this blocking.

Tumblr's robots.txt file blocks known AI data collection crawlers including GPTBot (OpenAI), ClaudeBot (Anthropic), and CCBot (Common Crawl), among others. Tumblr staff confirmed this policy in February 2024, stating they would continue to block AI crawlers "save for those with which we partner." In March 2024, Tumblr unblocked Bing's crawler after Microsoft changed its policy to no longer use indexed content for AI training without an explicit opt-in. Users who activate the "Prevent Third-Party Sharing" setting have their blogs added to an additional disallowed list for crawlers. The practice creates a visible tension: Tumblr blocks unauthorized scraping of user content while simultaneously licensing that same content to AI companies through paid deals.