Bolt launches Forge, an open-model lab built with Arcee AI

Bolt.new, the AI-powered full-stack app builder from StackBlitz, has a new mode called Forge, and the pitch is straightforward: more usage, open models, and a shot at building one of the largest publicly released AI models in existence. Forge launched on September 14, 2026, and it runs exclusively on open-source models. Pro plan subscribers get up to 50 times more usage at no additional cost through October 14, 2026, the catch being that users must opt in to share anonymized session data. That data, scrubbed of personal information, gets routed to Arcee AI to train a new class of open-weight models. What Forge actually does Forge currently runs on models including GLM 5.3 Flash and experimental variants. The performance gap between open and proprietary models is real but narrowing. Forge’s open models scored 92.2 on the Bolt Build Index, compared to 101.0 for the top paid model, a roughly 9% gap. Users who want the 50x usage boost share anonymized sessions. Users who don’t opt in keep their existing access unchanged. No data is retained that could identify individuals, and Bolt and Arcee have signed a formal data processing contract governing the arrangement. Arcee AI and the trill...