Add Zitadel to an existing app

In an app you already have, setup detects the framework and patches the app instead of scaffolding a new one. You need what the Quickstart needs. Commit your work, then run these in the app's directory:

npx @zitadel/cli@latest doctor
npx @zitadel/cli@latest start
npx @zitadel/cli@latest setup --server local

Setup asks the same questions and writes the same Zitadel files as for a new app (Scaffold auth). Then prove the browser flow as the Quickstart does.

What setup writes, by frameworkCopy Anchor Link

• Next.js and Nuxt: setup detects the framework and patches the app. Before it creates anything, it stops with E_CONFLICT rather than overwrite a file of yours that it would write, such as your own proxy.ts or app/login/page.tsx. Next.js runs one request boundary, so setup also stops on yours under the other name: on Next 16 it writes proxy.ts, and Next refuses to run beside a middleware.ts. Move yours aside, rerun setup, and merge it into the file setup writes. If package.json names Next.js by a tag such as latest, setup can't tell the version and writes middleware.ts, so it stops on an existing proxy.ts: pin the version the app runs, such as ^16.0.0, and rerun.
• SvelteKit, SolidStart, Qwik Router, and TanStack Start: setup detects the framework and writes the server hook or middleware (src/hooks.server.ts, src/middleware.ts, src/routes/plugin@nextgen.ts, or src/start.ts) plus the landing, login, register, and profile routes.
• React, Vue, Angular, Solid, Svelte, and Qwik: setup writes the app's root component to a fixed path: src/App.tsx (React, Solid), src/App.vue, src/App.svelte, src/app.tsx (Qwik), or src/app/app.ts (Angular). If your app has a file there, setup stops with E_CONFLICT on it, again before creating anything. It also reads the entry that mounts your root component, the script index.html loads or Angular's src/main.ts, and stops when that mounts one from another file, such as src/App.jsx or Angular 17–19's src/app/app.component.ts, because your app would never load setup's. Import the root from the path setup writes in that entry, rerun setup, and move what you need from yours into it.
• Other apps, such as a Next.js Pages Router app, a React app without Vite, or an app on a framework older than setup supports (Next.js 15.2.3, Nuxt 4, SvelteKit 3 with Svelte 5, SolidStart 2, Qwik Router and Qwik 2.0.0-beta.45, TanStack Start 1, React 18, Vue 3.2, Angular 17, Solid 1.6, Svelte 5): setup doesn't support them yet and stops without changing anything. Don't pass --force there: where setup detects no framework at all, --force makes it scaffold a new app over yours.

When setup stopsCopy Anchor Link

If you pass --framework, name the one your app uses: when setup detects another, it stops with E_CONFLICT instead of treating your app as a directory to scaffold into. The files setup writes under .zitadel/, such as the default schema and login flow, are checked before it creates the project too, so a conflict leaves nothing behind.

After an E_CONFLICT, the error's hint says what to change. For a file at a path setup writes, move it aside and rerun, or rerun with --force to let setup replace it and merge your version back from git. --force doesn't help with your root component or request boundary at another path, or with a connection under .zitadel/idps/, which setup never replaces.