API Reference

This page is a compact map of the public surface currently provided by NextFs.

It is not intended to replace the source file. Its purpose is to help you find the right module quickly when translating an App Router example from JavaScript or TypeScript into F#.

Items marked experimental depend on Next.js experimental flags or unstable_* upstream functions and may change without a NextFs major bump.

Components

Font

Bindings for next/font/local.

Common members:

  • Font.local

Related helpers and types:

  • FontOptions
  • LocalFontSource
  • FontDeclaration
  • LoadedFont
  • FontStyleObject
  • FontDisplay

GoogleFont

Generated named bindings for next/font/google.

Examples:

  • GoogleFont.Inter
  • GoogleFont.Roboto
  • GoogleFont.Roboto_Mono

For real next/font entry modules, prefer anonymous-record or object-literal options so Next.js can statically analyze the loader call.

Bindings for next/link.

Common members:

  • Link.create
  • Link.href
  • Link.hrefObject
  • Link.replace
  • Link.scroll
  • Link.prefetch
  • Link.prefetchAuto
  • Link.onNavigate
  • Link.transitionTypes

LinkClient

Client-only bindings for next/link.

Common members:

  • LinkClient.useLinkStatus

Image

Bindings for next/image.

Common members:

  • Image.create
  • Image.getImageProps
  • Image.src
  • Image.alt
  • Image.width
  • Image.height
  • Image.fill
  • Image.sizes
  • Image.quality
  • Image.preload
  • Image.priority
  • Image.loading
  • Image.placeholder
  • Image.blurDataUrl
  • Image.unoptimized
  • Image.overrideSrc

Related types:

  • ImagePropsResult

Script

Bindings for next/script.

Common members:

  • Script.create
  • Script.src
  • Script.strategy
  • Script.id
  • Script.onLoad
  • Script.onReady
  • Script.onError

Form

Bindings for next/form.

Common members:

  • Form.create
  • Form.action
  • Form.serverAction
  • Form.replace
  • Form.scroll
  • Form.prefetch

Bindings for next/head.

Common member:

  • Head.create

Server-safe bindings for next/navigation.

Common members:

  • Navigation.redirect
  • Navigation.redirectWith
  • Navigation.permanentRedirect
  • Navigation.notFound
  • Navigation.forbidden — experimental, requires experimental.authInterrupts: true
  • Navigation.unauthorized — experimental, requires experimental.authInterrupts: true
  • Navigation.unstableRethrow

Related types:

  • AppRouterInstance
  • LinkStatus
  • NavigateOptions
  • PrefetchOptions
  • ReadonlyURLSearchParams
  • URLSearchParamsCollection
  • RedirectType

These map to the App Router special files:

  • Navigation.notFound() -> not-found.js
  • Navigation.forbidden() -> forbidden.js
  • Navigation.unauthorized() -> unauthorized.js

Client-only bindings for App Router hooks.

Common members:

  • NavigationClient.useRouter
  • NavigationClient.usePathname
  • NavigationClient.useSearchParams
  • NavigationClient.useParams
  • NavigationClient.useSelectedLayoutSegment
  • NavigationClient.useSelectedLayoutSegments
  • NavigationClient.useSelectedLayoutSegmentFor
  • NavigationClient.useSelectedLayoutSegmentsFor
  • NavigationClient.useServerInsertedHTML
  • NavigationClient.unstableIsUnrecognizedActionError — experimental, wraps upstream unstable_* function

WebVitals

Bindings for next/web-vitals.

Common members:

  • WebVitals.useReportWebVitals

Related types:

  • WebVitalMetric
  • WebVitalMetricRating
  • WebVitalNavigationType

Server

Server

Bindings for next/headers and request-context helpers from next/server.

Common members:

  • Server.after
  • Server.afterAsync
  • Server.headers
  • Server.cookies
  • Server.draftMode
  • Server.connection
  • Server.userAgent
  • Server.userAgentFromString

Related types:

  • HeadersCollection
  • RequestCookieStore
  • CookieOptions
  • CookiePriority
  • CookieSameSite
  • DraftModeState
  • UserAgentInfo
  • UserAgentBrowser
  • UserAgentDevice
  • UserAgentEngine
  • UserAgentOperatingSystem
  • UserAgentCpu
  • NextRequest
  • NextUrl
  • FormDataCollection

ServerRequest

Constructors for NextRequest.

Common members:

  • ServerRequest.create
  • ServerRequest.createFrom
  • ServerRequest.createWithInit
  • ServerRequest.createFromWithInit

Related helpers and types:

  • NextRequestInit
  • NextConfig

ServerResponse

Static helpers over NextResponse.

Common members:

  • ServerResponse.create
  • ServerResponse.createWithBody
  • ServerResponse.createWithInit
  • ServerResponse.json
  • ServerResponse.jsonWithInit
  • ServerResponse.redirect
  • ServerResponse.redirectWithInit
  • ServerResponse.rewrite
  • ServerResponse.rewriteWithInit
  • ServerResponse.next
  • ServerResponse.nextWithInit

Related types:

  • NextResponse
  • ResponseInit
  • NextResponseInit
  • ResponseCookieStore

NextRequest and NextResponse also expose common Web Request / Response members used in route handlers and proxy flows:

  • clone
  • arrayBuffer
  • blob
  • formData
  • bodyUsed

ServerFetch

Bindings for Next.js server fetch() usage.

Common members:

  • ServerFetch.fetch
  • ServerFetch.fetchWithInit
  • ServerFetch.fetchFrom
  • ServerFetch.fetchFromWithInit

Related helpers and types:

  • ServerFetchInit
  • NextFetchOptions
  • ServerFetchResponse
  • ServerFetchCache
  • Revalidate

Proxy

Bindings used for proxy.js. Experimental — proxy support varies by Next.js version.

Common members:

  • ProxyConfig.create
  • ProxyConfig.matcher
  • ProxyConfig.matchers
  • ProxyConfig.matchersMany
  • ProxyConfig.regions
  • ProxyConfig.regionsMany
  • ProxyConfig.allowDynamic
  • ProxyConfig.allowDynamicMany
  • ProxyMatcher.create
  • ProxyMatcher.source
  • ProxyMatcher.localeFalse
  • ProxyMatcher.has
  • ProxyMatcher.missing
  • RouteHas.create
  • RouteHas.type'
  • RouteHas.key
  • RouteHas.value

Related types:

  • NextFetchEvent
  • RouteHasType

Instrumentation

Types intended for root instrumentation.js and instrumentation-client.js files.

Common types:

  • InstrumentationError
  • InstrumentationRequest
  • InstrumentationContext
  • InstrumentationRouterKind
  • InstrumentationRouteType
  • InstrumentationRenderSource
  • InstrumentationRevalidateReason
  • InstrumentationRenderType
  • RouterTransitionType

Special Files

Types intended for App Router special files:

  • ErrorBoundaryProps
  • ErrorWithDigest
  • TemplateProps
  • DefaultProps<'T>

These are typically used with:

  • error.js
  • global-error.js
  • template.js
  • default.js

Route handlers

Use:

  • NextRequest
  • RouteHandlerContext<'T>
  • [<CompiledName("GET")>], [<CompiledName("POST")>], and similar attributes

Cache

Directive

Inline directives currently provided:

  • Directive.useServer()
  • Directive.useCache()
  • Directive.useCachePrivate() — experimental, requires experimental.dynamicIO
  • Directive.useCacheRemote() — experimental, requires experimental.dynamicIO

Cache

Bindings for next/cache.

Common members:

  • Cache.cacheLifeProfile
  • Cache.cacheLifeProfileName
  • Cache.cacheLife
  • Cache.cacheTag
  • Cache.cacheTags
  • Cache.refresh
  • Cache.revalidatePath
  • Cache.revalidatePathType
  • Cache.revalidateTag
  • Cache.revalidateTagWithProfile
  • Cache.revalidateTagWithCustomProfile
  • Cache.updateTag
  • Cache.noStore

Related helpers and types:

  • CacheLife.create
  • CacheLife.stale
  • CacheLife.revalidate
  • CacheLife.expire
  • CacheProfile
  • RevalidatePathType
  • RevalidateTagProfile

Metadata And Special Files

Metadata

Top-level metadata object builders for layout/page exports.

Common members:

  • Metadata.create
  • Metadata.title
  • Metadata.titleTemplate
  • Metadata.description
  • Metadata.applicationName
  • Metadata.generator
  • Metadata.keywords
  • Metadata.creator
  • Metadata.publisher
  • Metadata.metadataBase
  • Metadata.alternates
  • Metadata.openGraph
  • Metadata.twitter
  • Metadata.robots
  • Metadata.manifest
  • Metadata.icons
  • Metadata.verification
  • Metadata.other

Related helper modules:

  • MetadataTitle
  • MetadataImage
  • MetadataAlternates
  • MetadataOpenGraph
  • MetadataTwitter
  • MetadataVerification
  • ThemeColor
  • Viewport

MetadataRoute

Builders for App Router metadata route files.

Common submodules:

  • MetadataRoute.RobotsRule
  • MetadataRoute.Robots
  • MetadataRoute.SitemapEntry
  • MetadataRoute.ManifestIcon
  • MetadataRoute.Manifest

Related types:

  • MetadataRoute.SitemapChangeFrequency

ImageMetadata

Builders for generateImageMetadata results.

Common members:

  • ImageMetadata.create
  • ImageMetadata.id
  • ImageMetadata.alt
  • ImageMetadata.size
  • ImageMetadata.contentType

Related helpers:

  • ImageMetadataSize
  • ImageGenerationProps<'routeParams, 'id>

ImageResponse

Bindings for ImageResponse from next/og.

Common members:

  • ImageResponse.create
  • ImageResponse.createWithOptions

Related helpers and types:

  • ImageResponseOptions
  • ImageResponseFont
  • ImageResponseEmoji
  • ImageResponseFontStyle

Page And Layout Props

Utility interfaces for async App Router props:

  • PageProps<'routeParams, 'searchParams>
  • LayoutProps<'routeParams>
  • ResolvingMetadata
  • ResolvingViewport
  • SitemapProps

Utility types

  • Href.create
  • Href.pathname
  • Href.query
  • Href.hash
  • PreferredRegion.auto
  • PreferredRegion.globalRegion
  • PreferredRegion.home
  • PreferredRegion.region
  • PreferredRegion.regions
  • GenerateSitemapsEntry.create
  • GenerateSitemapsEntry.id
  • Revalidate.forever
  • Revalidate.neverCache
  • Revalidate.seconds
  • RouteRuntime
  • LoadedFont
  • ScriptStrategy
  • ImageLoading
  • ImagePlaceholder

Tooling Attributes

NextFsEntryAttribute

Marks an F# module as a Next.js App Router entry point. The scanner (tools/nextfs-scan.mjs) reads this attribute to auto-generate nextfs.entries.json.

Must be placed immediately before the module declaration, before any open statements. Use the fully-qualified form [<NextFs.NextFsEntry(...)>].

[<NextFs.NextFsEntry("app/page.js", Directive="use client", Default="Page")>]
module App.Page

Parameters:

  • output (positional): wrapper output path, e.g. "app/page.js"
  • Directive: "use client" or "use server" (optional)
  • Default: named F# binding to re-export as the JavaScript default
  • Named: space-separated list of named exports, e.g. "metadata viewport"
  • ExportAll: true to emit export * from ...

NextFsStaticExportAttribute

Adds a static literal export to the generated wrapper. Use when Next.js needs a statically-analyzable literal that Fable cannot guarantee to produce.

[<NextFs.NextFsEntry("proxy.js", Named="proxy")>]
[<NextFs.NextFsStaticExport("config", """{"matcher":["/((?!_next).*)"]}""")>]
module Proxy

Parameters:

  • name (positional): export name, e.g. "config"
  • json (positional): JSON string to inline as the exported value

Notes

  • Keep route handlers and multi-argument server actions uncurried.
  • Annotate entry modules with [<NextFs.NextFsEntry>] and run npm run scan instead of writing nextfs.entries.json by hand.
  • Use wrapper files for file-level 'use client' and 'use server'.
  • For a full project layout, see the starter example.