# Next.js SDK @cohorly/nextjs re-exports / useCohorly() from the React SDK and adds createCohorlyProxy(), a first-party ingestion and feature-flag route handler so your project token never has to leave the server. ## Install ```bash pnpm add @cohorly/nextjs # or: npm install @cohorly/nextjs ``` Requires Next.js 13+ and React 18+ (peer dependencies). ## Two token modes There are two ways to attach your project token to ingested data. Pick one. ### 1. Client-side (token in the browser bundle) Pass `token` directly to ``. Simplest, but the token is visible in your client JS. ```tsx // app/layout.tsx import { CohorlyProvider } from "@cohorly/nextjs"; export default function RootLayout({ children, }: { children: React.ReactNode; }) { return ( {children} ); } ``` ### 2. Server-side proxy (token never leaves your server) Point the client SDK at a first-party API route and let the route handler inject the token server-side. Create the route with `createCohorlyProxy()`: ```ts // app/api/cohorly/[...path]/route.ts import { createCohorlyProxy } from "@cohorly/nextjs/server"; export const { POST } = createCohorlyProxy({ token: "YOUR_PROJECT_TOKEN", // injected server-side into every forwarded body // apiHost defaults to the hosted Cohorly API; set it to target a different deployment. }); ``` Then point `apiHost` at your own route and omit `token` on the client: ```tsx // app/layout.tsx {children} ``` The proxy forwards `POST /api/cohorly/track`, `/engage`, `/alias`, and `/flags/evaluate` upstream, stamping `token` into each forwarded body server-side. This keeps the token out of the browser bundle, hides `apiHost`, and dodges ad-blockers that block direct requests to third-party analytics hosts. ## createCohorlyProxy(options) | Option | Type | Notes | | -------------- | --------- | ------------------------------------------------------------------------------------------- | | `apiHost` | string | Optional upstream Cohorly server URL. Defaults to `https://cohorly-service.velloalabs.com`. | | `token` | string | Injected into every forwarded body. | | `allowedPaths` | string\[] | Defaults to `["track", "engage", "alias", "flags/evaluate"]`. | Returns a `{ POST }` route handler. Use the client provider and `useCohorly()` exactly as in the [React SDK](/sdks/react).