A federal appeals court on Monday handed major social media platforms a significant procedural defeat, ruling that tech giants cannot use Section 230 to dismiss thousands of lawsuits before going to trial.

In a 24-page opinion, a three-judge panel for the 9th U.S. Circuit Court of Appeals held that Section 230 of the Communications Decency Act — a 1996 law traditionally used to shield platforms from liability over third-party user content — provides a defense against liability, not complete immunity from being sued. The decision effectively blocks attempts by Meta Platforms Inc., ByteDance’s TikTok, Alphabet Inc.’s Google, and Snap Inc. to bypass jury trials.

Circuit Judge Jacqueline Nguyen’s written ruling clarifies that platform design decisions fall outside the early-exit protections long enjoyed by tech firms. Plaintiffs, including thousands of individuals, school districts, and state attorneys general, argue that features like infinite scroll, push notifications, and algorithmic recommendation feeds are engineered to exploit young users and encourage compulsive behavior.

Because Section 230 acts as a affirmative defense rather than an immunity from suit, the panel determined it lacked appellate jurisdiction to halt ongoing litigation prior to final trial judgments.

The ruling arrives at a critical moment for Big Tech.

Alongside rejecting the Section 230 appeal, the court denied Meta’s emergency request to delay a high-stakes trial scheduled to begin with jury selection in Oakland, Calif., federal court. Brought by the attorneys general of California, Colorado, Kentucky, and New Jersey, the lawsuit accuses Meta of illegally collecting children’s data and engineering addictive products. The states are seeking structural changes to platform designs alongside statutory penalties.

Monday’s decision builds on momentum established by recent bellwether trials. A Los Angeles jury previously found Meta and Google negligent in a design defect case, awarding $6 million in damages to a young woman who alleged platform addiction severely impacted her mental health. Additionally, a New Mexico judge recently finalized a $942 million judgment against Meta for child safety misrepresentations and public nuisance.

While Meta maintains it has instituted extensive teen safety features and denied wrongdoing, the 9th Circuit’s ruling ensures that internal company research and engineering practices will face intense scrutiny in courtroom settings. The precedent applies across the western United States, setting up a potentially transformative wave of product liability trials for the tech industry.