Integrate the Optimization Next.js SDK in a Next.js Pages Router app
Overview
Use this guide to render Contentful entries with personalized getServerSideProps first paint in a
Next.js Pages Router app, then hydrate the browser from the same Optimization handoff.
New to personalization? Here is the whole idea in four points:
- In Contentful you author variants of an entry and attach them to an experience - a rule that decides which visitors see which variant.
- When a page is requested, Contentful’s Experience API looks at the request context and picks the variant for each experience. Swapping a fetched entry for its picked variant is called resolving the entry.
- Your app hands a Contentful entry to the SDK at the point where that entry becomes output. The SDK gives back the selected variant, or the original entry when no variant applies - the baseline fallback. You can fetch the entry yourself or give the SDK your Contentful client and an entry ID; either way, the client stays yours.
- You render the returned entry with the same application components you already use.
That is enough to start. The guide introduces policy and optional capabilities at the point you need them.
You will get there in two milestones:
- Milestone 1 - Server-resolved first paint and matching hydration. The quick start below is shippable when your policy allows server personalization.
- Milestone 2 - Opt-in browser re-personalization after hydration. See Browser takeover and live updates.
This guide uses @contentful/optimization-nextjs/pages-router in browser-facing files and
@contentful/optimization-nextjs/pages-router/server in getServerSideProps helpers. The adapter
binds app-local configured components and a request handoff helper; your app still owns Contentful
fetching, consent policy, and response caching. If you use the App Router, use the
Next.js App Router guide
instead.
Quick start
This quick start assumes a Pages Router page already fetches a Contentful entry in
getServerSideProps and renders it with your own component. The proof is one entry whose variant
appears in View Source and stays stable after hydration. Consent is granted only to prove the wiring;
replace it in Consent, identity, profile, and reset.
-
Install the package and keep
contentfulapp-owned.Copy this:
-
Bind the browser-facing module for
_app.tsxand page components. This binding shares one configured helper set for the app; it is not a per-route or per-visitor isolation context.Adapt this to your use case:
-
Bind the server helper for
getServerSideProps. The server entry point is separate from the browser-facing module and returns a browserhandoff. This binding configures the server helper set; it is not a per-request isolation context. The quick start keeps entry fetching ingetServerSideProps; managed fetching is introduced later.Adapt this to your use case:
-
Mount the bound root once in
_app.tsx. When a handoff exists, the root owns the server’s page-event decision. When no handoff exists, the separate route tracker emits the first browser page event and tracks later navigations.Adapt this to your use case:
-
Merge the Optimization handoff with your page props.
Adapt this to your use case:
-
Wrap the entry renderer. A render prop is the function child
{(entry) => ...}; it lets you render the resolved entry with your existing component. This shortcut assumes the baseline and every eligible variant use theherocontent type. If a variant can use another content type, follow the skeleton-union and narrowing path in Personalizing entries.Adapt this to your use case:
-
Verify the result. In Contentful, target the experience to all visitors and give the variant a distinctive text value. Run the app, open View Source, and find that variant text in the raw HTML. Then load the page normally and confirm the same text remains after hydration.
Before you start
The sections below walk the integration in order. First, gather the few things you can only get from outside this guide:
-
A Next.js Pages Router app with
getServerSidePropson pages that need server-personalized first paint. -
A Contentful delivery client that can fetch the baseline entries your pages render.
-
Contentful space, environment, delivery token, and one concrete locale. Fetch entries with that locale and enough
includedepth for linked Optimization entries and variants. -
At least one entry with a variant attached to an experience, authored in Contentful. Without an authored variant, the integration can still run correctly while returning the baseline, so you cannot yet distinguish working personalization from a content-authoring gap. For the first personalized-content test, target all visitors so the test request or visitor matches automatically.
-
Your Contentful space values — space ID and environment, from your Contentful space settings. Find them in the Contentful web app under Apps → Installed apps → Contentful Personalization → SDK keys. The space ID and environment are safe to expose to the browser.
The Experience and Insights API base URLs default correctly; you only set them for mocks or non-default hosts (see How the SDK fits your app).
You do not need a setup inventory up front. Everything else — the server helper, the root, entry wrapping, consent, tracking — is introduced by the section that needs it.
Match your app’s browser environment-variable convention. Next.js exposes NEXT_PUBLIC_* values
to the browser; unprefixed server values stay server-only.
Core integration
How the SDK fits your app
Integration category: Required for first integration
Pages Router integrations have an explicit client/server split:
Use the server entrypoint only from server files. Use the browser-facing module for _app.tsx and
components.
Fetching Contentful entries
Integration category: Required for first integration
Manual entry source is the usual Pages Router path: getServerSideProps fetches a baseline entry and
passes it through props, then the page renders it through OptimizedEntry.
Managed entry source is also available when the route knows an entry ID or a content type and slug.
Pass prefetchManagedEntries to createRequestHandoff() in getServerSideProps; the helper puts
the baseline snapshots in handoff.entries so the browser can preserve managed entries without a
Contentful Delivery API (CDA) round trip. Server prefetch accepts a direct descriptor shaped as
{ contentType, slug, slugField?, entryQuery? }; OptimizedEntry receives that descriptor under
managedEntry. slugField defaults to slug.
Managed fetching needs the app-owned Contentful client in both bindings: the server binding uses it
for prefetch, and the browser binding uses it if a managed source must fetch after hydration. It also
extends the app-owned getContentfulOptimization wrapper with the descriptors for the current page.
Adapt this to your use case: add managed fetching only if a page passes an ID or descriptor to
OptimizedEntry. Keep contentfulClient in your existing Contentful module.
For a dynamic route, define the source once from the route parameter. contentType, slug,
slugField, and entryQuery are fixed SDK property names. Their values — including the content type
ID, slug field ID, route slug, locale, and include depth — come from your app and content model.
Adapt this to your use case:
Use that same object for server prefetch and browser rendering:
Adapt this to your use case:
Slug lookup merges the normal managed query, then enforces content_type,
fields.<slugField>, and limit: 2. These are the exact failure templates:
- No match:
Contentful entry not found for content type "<contentType>" where "fields.<slugField>" equals "<slug>". - More than one match:
Multiple Contentful entries found for content type "<contentType>" where "fields.<slugField>" equals "<slug>".
The angle-bracketed placeholders are replaced with the source’s actual content type, effective slug
field, and slug. The handoff nests the normalized descriptor under managedEntry, retains the
fetched entry’s real sys.id as entryId, and lets the browser render reuse it when contentType,
slug, the effective slugField, and effective entryQuery values match. Changing the locale,
include depth, custom slug field, or another query value creates a different source and therefore
does not reuse this handoff entry. Resolution metadata and interaction tracking use the real ID, not
the slug.
The getServerSideProps request handoff and the profile cookie
Integration category: Required for first integration
createRequestHandoff(context, options) reads the Pages Router request, evaluates
consent.server, calls the request page event, persists the SDK-owned anonymous profile cookie on
the response when appropriate, and returns a serializable browser handoff.
Configure consent.server explicitly. If it is omitted, Pages Router request consent resolves to
false.
The returned handoff also carries browser defaults derived from the resolved server consent. When
_app.tsx passes that handoff to the bound root, those handoff defaults override matching
consent.clientDefaults axes for the first browser runtime; clientDefaults remains the fallback
for routes without a request handoff.
The SDK-owned anonymous profile cookie is ctfl-opt-aid. Your app owns any consent cookie or account
record that consent.server reads. Pages Router server work happens in getServerSideProps; there
is no middleware or proxy requirement for the Pages Router path.
The bound root and page events
Integration category: Required for first integration
The bound OptimizationProvider handles the content SDK context, handoff, hydration mode, and
managed-entry prefetch for a subtree. Use the bound OptimizationRoot in _app.tsx because it adds
initial page-event wiring. Pass routeKey and buildPagePayload so the root can follow the
handoff’s initialPageEvent instruction; those props do not belong on OptimizationProvider. The
separate NextPagesAutoPageTracker should emit the initial event when no handoff exists and skip it
when a handoff lets the root own that first route, then track later client navigations.
Campaign inputs follow page-event ownership. The pagePayload passed to createRequestHandoff
shapes the first server page event. The root’s buildPagePayload shapes a browser event that the root
owns; in beforeInitialPage mode, it supplies both the direct attempt and later route emissions. In
normal tracker mode, NextPagesAutoPageTracker instead derives page.url from the current router URL
for later navigations. For either payload seam, campaign is an optional top-level object with
name, source, medium, term, and content fields, while url is nested under the optional
properties object. When those inputs are absent, the server request, browser page provider, or
router tracker supplies page.url for the event it owns.
For each event, the SDK chooses one whole campaign source in order: top-level campaign, then a
properties.url containing at least one supported UTM parameter, then page.url. An explicit empty
campaign: {} suppresses URL inference and produces empty attribution. Once a source is chosen,
missing fields are not filled from a lower-priority URL. The chosen URL maps into
context.campaign: utm_campaign becomes name, utm_source becomes source, utm_medium
becomes medium, utm_term becomes term, and utm_content becomes content. page.referrer
remains page metadata, but it is not a campaign source.
As an optional alternative, the browser binder accepts beforeInitialPage for an owned content
root that must finish returned identity or custom Experience event work before its initial page
decision. The initial page decision is the root’s one choice to send the first browser page
event or skip it because an applied handoff already owns that route. During getServerSideProps,
the server helper can accept the page event and record that ownership in the handoff. _app.tsx
passes the handoff to the browser root; after its live owned runtime exists, the root invokes the
callback, makes one direct page attempt or same-route handoff skip, marks the attempted route, and
emits for later route changes.
The binder captures the callback only for its bound OptimizationRoot; its bound
OptimizationProvider and OptimizationAnalyticsRoot do not receive it. Here, identity means
the visitor ID and traits your application is allowed to send; the full lifecycle is covered in
Consent, identity, profile, and reset. The callback runs once
after that live owned runtime exists, during a retained root lifetime that ends when the root
unmounts. A real remount starts another lifetime. Its SDK-provided
BeforeInitialPageClient exposes methods that stay bound when destructured: identify supplies
visitor identity, screen records a screen-view Experience event, and track sends an app-named
custom Experience event.
Return one value that represents all before-initial-page operations. A JavaScript Promise
represents work that finishes later; a thenable is a Promise-like object with a .then() method.
An async callback returns one Promise automatically, and every operation you await becomes part
of that returned work. A standalone OptimizationProvider with an injected SDK does not accept
this option.
Adapt this to your use case: add the callback to the existing browser binding and stop exporting
the separate tracker for this path. app-user-id and client_ready are app-owned identifiers in
this example; replace them with the browser identity store and custom event name your app owns.
The before-initial-page root requires routeKey and lazy buildPagePayload. It does not accept
initialPagePayload, the eager page data object computed before later route changes. The _app.tsx
root in the quick start already supplies the two required values. Remove only the separate tracker
from this before-initial-page subtree; leaving it mounted creates a second page owner.
Adapt this to your use case: keep the handoff, current route key, lazy payload builder, and page
component from your existing _app.tsx.
A direct page attempt means the root calls the page-event API itself once before automatic route
tracking starts. The root’s page emitter is its built-in route-change logic, not a tracker
component you mount. After the direct attempt finishes, its initial skip mark records the attempted
route as handled without sending another event. A later route change makes the emitter send its
normal page event. If the page call returns { accepted: false }, the SDK finished the call but did
not admit that page event locally; the sequence still advances without an immediate same-route
retry.
The watchdog uses 3,000 ms when maxWaitMs is omitted and accepts any positive finite value. A
value of 0, a negative number, NaN, Infinity, or -Infinity synchronously throws
TypeError('beforeInitialPage.maxWaitMs must be a positive finite number.') before the provider,
callback, page, onError, or watchdog runs. A callback throw, returned-work rejection, or watchdog
expiry is reported to onError when supplied. While the root remains mounted and the same live
owned runtime is current, the root still attempts the page.
The watchdog stops waiting but does not cancel callback code or a request it already sent. Fire-and-forget work that the callback does not return can finish after the page. If the root unmounts or its live runtime is replaced, only unsent local page and readiness continuation is suppressed; work already started is not canceled.
A route change after the direct page attempt starts neither cancels that attempt nor starts a competing page attempt. The root settles and marks the captured attempted route before enabling later page emission. A route observed only while the attempt is in flight is not emitted; a route change after readiness emits normally.
If callback and page work remain pending when an entry reaches its existing five-second fallback deadline, the entry can reveal baseline content. With live updates disabled, that first visible content stays frozen even if the before-initial-page work later selects a variant. Enable Browser takeover and live updates only when a late replacement is intended.
Use the accepted and blocked event streams introduced in Analytics forwarding for a development-only ordering check.
Adapt this to your use case: temporarily add this observer to the same browser binding. It logs complete event records and removes both subscriptions when the root tears down.
Set the example identity first with
localStorage.setItem('app-user-id', 'guide-user'), then reload the page that uses
beforeInitialPage. The identify and client_ready results must appear, as accepted or blocked
calls, before at most one initial page result. Navigate once and confirm one later page result.
An initial page before
callback completion or two initial page results usually means the separate tracker is still
mounted. These streams prove local SDK admission or blocking, not API delivery.
The Pages server binder deliberately rejects NextjsClientOptimizationConfigWithBeforeInitialPage
through its beforeInitialPage?: never parameter boundary. The callback remains browser-only:
the server binder does not run it or serialize it into the handoff that the app passes through page
props. Direct Web and Node integrations keep this ordering in application code by awaiting their
identity or custom-event work before calling their existing page-event API.
Personalizing entries
Integration category: Required for first integration
OptimizedEntry receives a baselineEntry fetched by your page, a managed entryId plus optional
entryQuery, or a content-type/slug descriptor under managedEntry. The descriptor can also set
slugField and entryQuery. Its render prop receives the resolved entry. If no
experience applies, consent is denied, the API has no variant, or a linked variant cannot be
resolved, the render receives the baseline entry.
isEmptyVariant === true marks the SDK renderer’s no-content state. It differs from the fallback
cases above, which render the baseline entry. In the no-content state, OptimizedEntry keeps its
host and tracking attributes but does not invoke or render app content. The standalone
ServerOptimizedEntry, imported from @contentful/optimization-nextjs/server, is the lower-level
renderer for server code that already has a full resolver result and static children; it keeps its
server-rendered host and tracking attributes while omitting those children. An absent empty-variant
flag renders normally.
A resolved selected variant can use any Contentful content type.
A Contentful entry skeleton is a TypeScript type that names a content type ID and its fields.
Use one skeleton union, S, containing every possible baseline or variant content type. The bound
OptimizedEntry with baselineEntry uses <S, M, L>, where M is the contentful.js response
mode and L is the locale type. A managed ID or slug source uses <S, L> because M is fixed to
undefined. When every variant shares the baseline content type, omit the generic and let
TypeScript infer that skeleton from baselineEntry.
Follow this pattern: declare the complete skeleton union in the page renderer and narrow in the render prop, where the resolved entry becomes page markup. The guard compares the Contentful content type ID; it does not validate fields.
The union is a compile-time model, not a runtime filter. Narrow at the renderer boundary before reading content-type-specific fields. For lower-level resolver, managed-fetch, open-ended model, and event-stream examples, see TypeScript content-model choices.
Avoid nesting two OptimizedEntry wrappers for the same baseline entry. Put the wrapper at the point
where the app turns the entry into output.
Browser takeover and live updates
Integration category: Common but policy-dependent
The handoff controls the first browser render over server HTML. liveUpdates controls whether
entries may re-resolve after startup when consent, identity, profile, or preview state changes.
Keep the default locked behavior for stable first paint. Turn on liveUpdates in the binding config
or on a specific entry only when visible content should react after hydration.
Entry interaction tracking
Integration category: Common but policy-dependent
OptimizedEntry emits view, click, and hover tracking from the resolved entry by default. Configure
global defaults with trackEntryInteraction in the browser-facing binding config and use per-entry props
for local opt-outs. Interaction delivery still depends on event consent and profile continuity.
Consent, identity, profile, and reset
Integration category: Common but policy-dependent
Replace the quick-start consent shortcut with your app policy:
- Read the app-owned consent record in the server helper’s
consent.server; omitted request consent resolves tofalse. - Seed conservative browser defaults through
consent.clientDefaultsfor routes without a request handoff. - Mirror browser choices to the app-owned consent record before the next request.
- Use
setConsent,identifyUser, andresetUserfrom/clienthooks for browser actions.
For request-handoff routes, defaults derived from the resolved consent.server decision travel in
the handoff and take precedence over matching consent.clientDefaults axes. Keep the two policies
aligned so hydration starts from the same consent decision the server used.
Adapt this to your use case:
app-consent is reader-owned in this example. The SDK reads only the decision you pass to it.
Optional integrations
Looking for optional before-initial-page work? Because it changes first-page ownership, its setup and verification live in The bound root and page events.
Analytics forwarding
Integration category: Optional
Forward accepted events from states.eventStream after onStatesReady runs. Deduplicate by
messageId, keep vendor consent separate from Contentful event consent, and use
states.blockedEventStream for diagnostics instead of replay.
The runtime event stream remains model-agnostic because it can carry interactions for entries of
every content type. If you read event.optimization?.resolvedEntry, narrow that entry with
isEntryOfContentType at the point of use; resolver-specific S types do not flow into a
later event.
For the full pattern, use Forward Optimization SDK context to analytics and tag-management tools.
Merge tags and Custom Flags
Integration category: Optional
The OptimizedEntry render prop also receives getMergeTagValue. Pass it to your Rich Text
renderer when entries contain SDK-owned merge-tag entries. Use /client hooks for browser-only
Custom Flags when a page needs reactive flag reads after hydration.
Follow this pattern:
Preview panel
Integration category: Optional
Attach @contentful/optimization-web-preview-panel only in development, preview, or staging
environments. The panel needs the live browser SDK and a Contentful client or pre-fetched audience
and experience entries. Keep the environment gate app-owned; do not ship editor tooling to ordinary
production visitors.
Advanced integrations
Mixed route strategies
Integration category: Advanced or production-only
Choose route ownership deliberately:
Pages Router static generation does not have request context. Use
createPublicPermutationHandoff() only when your application supplies app-owned selected
optimizations for a static or ISR permutation. The helper serializes those selections and cache
metadata; it does not discover public permutations or derive selected optimizations from route,
cookie, header, locale, or cache-key inputs. The maintained reference route uses a finite
getStaticPaths() registry with fallback: false; fallback: 'blocking' is a later option for
larger registries after you define how uncached public permutations are approved.
Each resolveEntriesForSelections() item includes optional isEmptyVariant. When it is true, the
item retains the baseline entry for tracking context, but direct page output must omit consumer
content.
Follow this pattern: return null for the empty result and branch on that value in the page.
Hero is your app-owned renderer; the page never passes null to OptimizedEntry as a
baselineEntry.
The page treats a null hero prop as no consumer output. The handoff still carries the selected
optimization state needed by the browser runtime.
For complete static, ISR, edge rendering, and analytics-only recipes, use Render personalized Next.js routes with static, ISR, and edge handoffs. For the mechanics behind handoff state and cache scopes, use Optimization handoff and cache-safe rendering.
Manual server and client escape hatches
Integration category: Advanced or production-only
Use lower-level subpaths only when the bound Pages Router path cannot express the route. The main
escape hatches are /server for direct Node request control with
configureNextjsServerOptimization(...), /client for router-neutral React roots and hooks, and
/tracking-attributes for manually rendered analytics-only markup.
configureNextjsServerOptimization(...) configures a stateless server runtime; it is not a
request-isolation context. Manual flows still pass handoff to a React root.
Lower-level resolver calls keep selections as the optional second positional argument:
resolveOptimizedEntry(entry, selectedOptimizations). Managed fetch calls accept an ID or a
source object shaped as { contentType, slug, slugField?, entryQuery? }. The ID overload receives
its query in FetchOptimizedEntryOptions; the slug source object carries entryQuery itself.
ServerOptimizedEntry<TElement, S, M, L> places the element type first, followed by the complete
skeleton union, response mode, and locale.
When lower-level code renders a resolver result directly, isEmptyVariant === true marks the SDK
renderer’s no-content state; check it before rendering entry. The result retains the baseline
entry and selection context for tracking even when consumer output is empty.
Caching and request policy
Integration category: Advanced or production-only
private-request handoffs include request-specific state and must not be stored in a shared public
cache. Catch Experience API failures according to your app’s policy; many apps return baseline props
when personalization is unavailable.
Use the handoff concept to review why request profile state must stay out of public caches, and use the supplemental rendering guide for static and ISR public permutation handoff patterns.
Follow this pattern:
Strict consent and duplicate-event controls
Integration category: Advanced or production-only
When no Optimization event may emit before explicit consent, configure a strict event policy and
return false from consent.server until your app-owned consent record is accepted. Use
initialPageEvent="skip" only when a handoff lets the root own the same route’s first page event.
Use blocked-event diagnostics to verify denied events are dropped at the SDK boundary.
Production checks
- Confirm server and browser config use the intended Contentful space, environment, locale, and Contentful space ID.
- Confirm
consent.server, request handoff defaults, browser consent defaults, and app-owned consent storage agree. - Confirm
ctfl-opt-aidis browser-readable where server and browser profile continuity is needed. - Confirm first-page ownership matches one mode. In normal tracker mode, the separate tracker skips
a server-owned first event and emits later routes. In
beforeInitialPagemode, no tracker is mounted and the root’s direct attempt plus built-in emitter do not duplicate the initial route. - Confirm baseline fallback is acceptable when no variant applies or Contentful links are unresolved.
- Confirm request-personalized output is never stored in a public shared cache.
- Run the maintained reference implementation or your app’s equivalent typecheck, lint, build, and browser E2E checks.