Inertia.js v3 Is Out: The Upgrade Guide Every Laravel Developer Actually Needs

Originally published at hafiz.dev Inertia.js v3 went stable on March 25. If you missed the announcement, it's a real major release, not one of those "major" bumps that changes nothing. Axios is gone, ESM is the only output format, React 18 and Svelte 4 are both dropped, and a handful of event names and APIs have changed. There's also a config file restructure that'll catch you off guard if you don't read the upgrade guide first. The good news: v3 is genuinely better. The bundle is smaller, SSR works in dev without a separate Node.js process, and two new APIs (the useHttp hook and optimistic updates) solve problems that previously needed awkward workarounds. If you've been putting off upgrading to take stock of the situation first, this post is for you. We also just went through a similar exercise with the Laravel 12 to 13 upgrade , which had zero breaking changes. Inertia v3 is different. Worth actually reading before you touch anything. What's Actually New in v3 Before we get into wha