Next.js (Pages Router) quickstart
1. Install hypertune
hypertune
Once you have a Next.js application (using the Pages Router) ready, install Hypertune's JavaScript SDK:
npm install hypertune
2. Set environment variables
Define the following environment variables in your .env
file:
NEXT_PUBLIC_HYPERTUNE_TOKEN=token
HYPERTUNE_FRAMEWORK=nextPages
HYPERTUNE_OUTPUT_DIRECTORY_PATH=generated
Replace token
with your main project token which you can find in the Settings tab of your project.
3. Generate the client
Generate a type-safe client to access your flags by running:
npx hypertune
4. Use the client
Add a new file called getHypertune.ts
that exports a getHypertune
function:
import { createSourceForServerOnly } from '@/generated/hypertune'
const hypertuneSource = createSourceForServerOnly({
token: process.env.NEXT_PUBLIC_HYPERTUNE_TOKEN!,
})
export default async function getHypertune({
isApiRoute = false,
}: {
isApiRoute?: boolean
} = {}) {
await hypertuneSource.initIfNeeded()
hypertuneSource.setRemoteLoggingMode(
isApiRoute ? 'normal' : 'off'
)
return hypertuneSource.root({
args: {
context: {
environment: process.env.NODE_ENV,
user: {
id: 'e23cc9a8-0287-40aa-8500-6802df91e56a',
name: 'Example User',
email: '[email protected]',
},
},
},
})
}
To use flags in components, first create a new <AppHypertuneProvider>
component that wraps the generated <HypertuneProvider>
component:
import { HypertuneProvider } from '@/generated/hypertune.react'
export default function AppHypertuneProvider({
children,
}: {
children: React.ReactNode
}) {
return (
<HypertuneProvider
createSourceOptions={{
token: process.env.NEXT_PUBLIC_HYPERTUNE_TOKEN!,
}}
rootArgs={{
context: {
environment: process.env.NODE_ENV,
user: {
id: 'e23cc9a8-0287-40aa-8500-6802df91e56a',
name: 'Example User',
email: '[email protected]',
},
},
}}
>
{children}
</HypertuneProvider>
)
}
Wrap your app with the <AppHypertuneProvider>
component in _app.tsx
:
import type { AppProps } from 'next/app'
import AppHypertuneProvider from '@/components/AppHypertuneProvider'
import '@/styles/globals.css'
export default function App({ Component, pageProps }: AppProps) {
return (
<AppHypertuneProvider>
<Component {...pageProps} />
</AppHypertuneProvider>
)
}
Then use the generated useHypertune
hook:
import { useHypertune } from '@/generated/hypertune.react'
export default function ExampleComponent() {
const hypertune = useHypertune()
const exampleFlag = hypertune.exampleFlag({ fallback: false })
return <div>Example Flag: {String(exampleFlag)}</div>
}
If you access a flag immediately after the app loads, you'll get your hardcoded fallback value if the SDK hasn't initialized from Hypertune Edge yet. This can result in layout shift or a flicker if the flag value changes when the SDK initializes.
To avoid this, wrap your page with the generated <HypertuneHydrator>
and <HypertuneRootProvider>
components, passing them dehydratedState
and rootArgs
from the server:
import {
GetServerSideProps,
InferGetServerSidePropsType,
} from 'next'
import ExampleComponent from '@/components/ExampleComponent'
import { DehydratedState, RootArgs } from '@/generated/hypertune'
import {
HypertuneHydrator,
HypertuneRootProvider,
} from '@/generated/hypertune.react'
import getHypertune from '@/lib/getHypertune'
type Props = {
dehydratedState: DehydratedState | null
rootArgs: RootArgs
}
export const getServerSideProps = (async () => {
const hypertune = await getHypertune()
const dehydratedState = hypertune.dehydrate()
const rootArgs = hypertune.getRootArgs()
return { props: { dehydratedState, rootArgs } }
}) satisfies GetServerSideProps<Props>
export default function Page({
dehydratedState,
rootArgs,
}: InferGetServerSidePropsType<typeof getServerSideProps>) {
return (
<HypertuneHydrator dehydratedState={dehydratedState}>
<HypertuneRootProvider rootArgs={rootArgs}>
<ExampleComponent />
</HypertuneRootProvider>
</HypertuneHydrator>
)
}
Notes
Dynamic rendering: Using
getServerSideProps
makes your entire page dynamic. To use flags and run experiments on static pages (e.g. marketing pages), see the guide on using Hypertune on static pages.Content Security Policy: If you have a CSP, add the following to your
connect-src
directive:https://edge.hypertune.com https://gcp.fasthorse.workers.dev
. This enables reporting of flag evaluations, experiment exposures, and analytics events.
5. (Optional) Add the Hypertune Toolbar
The Hypertune Toolbar lets you view and override feature flags directly in your frontend. Follow the guide to add it to your app.
6. (Optional) Include a build-time snapshot
To improve reliability, you can include a snapshot of your flag logic in the generated client at build time. The SDK will instantly initialize from the snapshot first before fetching the latest flag logic from Hypertune Edge.
Add the following environment variable to your .env
file:
HYPERTUNE_INCLUDE_INIT_DATA=true
Then regenerate the client.
You can keep the snapshot fresh by setting up a webhook to regenerate the client on every Hypertune commit. In this case, you don't need to initialize from Hypertune Edge at all, eliminating network latency and bandwidth, improving both performance and efficiency.
7. (Optional) Use Vercel Edge Config
If your Next.js app is deployed on Vercel, you can use Edge Config to initialize the Hypertune SDK on the server with near-zero latency.
1. Install the integration
Go to the Hypertune page in the Vercel Integrations marketplace and click "Add Integration".
Select your Vercel team and project.
Continue and log into Hypertune.
Connect your Hypertune project to a new or existing Edge Config store. Copy the displayed environment variables for later. They contain your Hypertune Token, Edge Config Connection String and Edge Config Item Key.
Go to your Vercel dashboard and select the project you want to use the Hypertune integration with. Go to Settings > Environment Variables and add the following:
NEXT_PUBLIC_HYPERTUNE_TOKEN
, set to your Hypertune TokenEDGE_CONFIG
, set to your Edge Config Connection StringEDGE_CONFIG_HYPERTUNE_ITEM_KEY
, set to your Edge Config Item Key
2. Use the integration
Pull the environment variables to your .env.development.local
file by running:
vercel env pull .env.development.local
Install the @vercel/edge-config
package:
npm install @vercel/edge-config
Finally, update your getHypertune
function to create an Edge Config client and pass it along with your Edge Config Item Key when creating the Hypertune source:
import { createClient } from '@vercel/edge-config'
import { VercelEdgeConfigInitDataProvider } from 'hypertune'
import { createSourceForServerOnly } from '@/generated/hypertune'
const hypertuneSource = createSourceForServerOnly({
token: process.env.NEXT_PUBLIC_HYPERTUNE_TOKEN!,
initDataProvider:
process.env.EDGE_CONFIG &&
process.env.EDGE_CONFIG_HYPERTUNE_ITEM_KEY
? new VercelEdgeConfigInitDataProvider({
edgeConfigClient: createClient(
process.env.EDGE_CONFIG
),
itemKey: process.env.EDGE_CONFIG_HYPERTUNE_ITEM_KEY,
})
: undefined,
})
export default async function getHypertune() {
await hypertuneSource.initIfNeeded() // Check for flag updates
return hypertuneSource.root({
args: {
context: {
environment: process.env.NODE_ENV,
user: {
id: 'e23cc9a8-0287-40aa-8500-6802df91e56a',
name: 'Example User',
email: '[email protected]',
},
},
},
})
}
Next steps
Now you can update the logic for exampleFlag
from the Hypertune UI without updating your code or waiting for a new build, deployment, or app release.
To add a new flag, create it in the Hypertune UI then regenerate the client.
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