Lovable announced OJ on 15 September 2026 and is moving previews onto it gradually. OJ is a Rust-based development server intended to reduce the wait before an AI-built app becomes usable in preview. It is a change beneath the preview, not a feature everyone must configure. Official explanation
Contents — jump to a section
Read the speed claim carefully
Lovable reports a median preview load falling from 17.4 to 8 seconds in its production experiment. These are the provider's measurements, not PickByTask's results or a guarantee for your project.
The separate synthetic comparison has an important caveat: the Vite setup included a type-checking plugin that OJ did not host. Do not treat that comparison as identical work completed faster.
Visit Lovable ↗What builders should watch
During a gradual rollout, a colleague's preview may behave differently from yours. For your own check, use the same project and record the wait, whether the page finishes loading, and whether edits appear correctly. Repeat a few ordinary edits rather than judging from one unusually fast load.
A quicker preview is useful feedback; it does not prove that generated logic, permissions or data writes are correct. Keep those acceptance checks separate. Our AI demo repeatability guide explains that distinction.
Source checked 16 September 2026. We have not benchmarked OJ or tested plugin compatibility.