Reddit sues Anthropic over "systematic theft" of user data to train AI models

Reddit has filed a lawsuit against Anthropic, alleging that the AI company illegally scraped vast amounts of user data from Reddit's platform to train its AI models, including the widely used chatbot, Claude. The 41-page complaint, filed on June 4, 2025, in the Superior Court of California alleges breach of contract, unjust enrichment, trespass to chattels, tortious interference with contract, and unfair competition against Anthropic.

Blatant disregard of policy and user privacy

According to the complaint, Reddit claims that Anthropic has been training its AI models on Reddit users' posts since at least December 2021, without authorization and in direct violation of Reddit's User Agreement.

Reddit asserts that its User Agreement prohibits the commercial exploitation of its services or content without a written agreement. Moreover, Anthropic has repeatedly ignored technological measures designed to prevent scraping, such as robots.txt files and IP rate limits.

Reddit emphasizes that it has established a market for licensing its content, enabling it to impose "meaningful guardrails" to protect user privacy and ensure accuracy. Companies like OpenAI and Google, Reddit states, have entered into formal partnerships and licensing agreements to access public Reddit content, respecting Reddit's terms and user interests. Anthropic, however, is accused of refusing to engage in such agreements.

Tabled evidence

The complaint cites Anthropic's own researchers, including CEO Dario Amodei, acknowledging the use of Reddit datasets to "finetune" its language models. There is also evidence that Anthropic scraped high-quality subreddit data for training, with the lawsuit even naming specific communities like r/AskHistorians, r/relationship_advice, and r/IAmA.

Furthermore, Claude itself, when queried, reportedly confirms it was "trained on at least some Reddit data as part of [its] broader training dataset."

Reddit also alleges that, despite Anthropic's public claims in July 2024 that it had blocked its bots from accessing Reddit, audit logs show continued access attempts over one hundred thousand times in subsequent months.

Impact on Reddit and users

Reddit argues that Anthropic's unauthorized commercial use of its content not only harms Reddit by denying it licensing revenue and increasing server traffic costs but also compromises user privacy.

Without a licensing agreement, Reddit cannot ensure that user deletion requests are respected or that sensitive content is not misused. The lawsuit points to Reddit's Compliance API, which notifies licensees when users delete posts or comments, a mechanism Anthropic allegedly bypasses.

Relief sought

The lawsuit seeks specific performance, compensatory damages, consequential damages, lost profits, and/or disgorgement of Anthropic's profits. Reddit is also requesting an injunction to prohibit Anthropic from continuing to use any Reddit data or content in support of its commercial offerings and from profiting from any commercial offerings built with the aid of Reddit content.

Additionally, Reddit is demanding restitution for the amount by which Anthropic has been enriched, along with pre-judgment and post-judgment interest, punitive damages, and attorneys' fees and costs.

The case is yet another example of the growing friction between AI developers and content platforms over the data used to train generative models. It follows similar suits filed by The New York Times, authors, and visual artists, and could help set legal precedents for how courts interpret data scraping and training rights.