diff --git a/example/example.cabal b/example/example.cabal
--- a/example/example.cabal
+++ b/example/example.cabal
@@ -14,11 +14,10 @@
   swagger.json
 
 tested-with:
-  GHC ==8.4.4
-   || ==8.6.5
+  GHC ==8.6.5
    || ==8.8.4
-   || ==8.10.4
-   || ==9.0.1
+   || ==8.10.7
+   || ==9.0.2
 
 library
   ghc-options:      -Wall
diff --git a/servant-openapi3.cabal b/servant-openapi3.cabal
--- a/servant-openapi3.cabal
+++ b/servant-openapi3.cabal
@@ -1,5 +1,5 @@
 name:                servant-openapi3
-version:             2.0.1.3
+version:             2.0.1.4
 synopsis:            Generate a Swagger/OpenAPI/OAS 3.0 specification for your servant API.
 description:
   Swagger is a project used to describe and document RESTful APIs. The core of the 
@@ -29,11 +29,10 @@
 build-type:          Custom
 cabal-version:       1.18
 tested-with:
-  GHC ==8.4.4
-   || ==8.6.5
+  GHC ==8.6.5
    || ==8.8.4
-   || ==8.10.4
-   || ==9.0.1
+   || ==8.10.7
+   || ==9.0.2
 
 extra-source-files:
     README.md
@@ -81,8 +80,8 @@
                      , bytestring                >=0.10.8.1 && <0.11
                      , http-media                >=0.7.1.3  && <0.9
                      , insert-ordered-containers >=0.2.1.0  && <0.3
-                     , lens                      >=4.17     && <5.1
-                     , servant                   >=0.17     && <0.19
+                     , lens                      >=4.17     && <5.2
+                     , servant                   >=0.17     && <0.20
                      , singleton-bool            >=0.1.4    && <0.2
                      , openapi3                  >=3.0.0    && <3.3
                      , text                      >=1.2.3.0  && <1.3
diff --git a/src/Servant/OpenApi/Internal.hs b/src/Servant/OpenApi/Internal.hs
--- a/src/Servant/OpenApi/Internal.hs
+++ b/src/Servant/OpenApi/Internal.hs
@@ -38,6 +38,9 @@
 import           Servant.API
 import           Servant.API.Description    (FoldDescription, reflectDescription)
 import           Servant.API.Modifiers      (FoldRequired)
+#if MIN_VERSION_servant(0,19,0)
+import           Servant.API.Generic        (ToServantApi)
+#endif
 
 import           Servant.OpenApi.Internal.TypeLevel.API
 
@@ -414,6 +417,11 @@
 #if MIN_VERSION_servant(0,18,2)
 instance (HasOpenApi sub) => HasOpenApi (Fragment a :> sub) where
   toOpenApi _ = toOpenApi (Proxy :: Proxy sub)
+#endif
+
+#if MIN_VERSION_servant(0,19,0)
+instance (HasOpenApi (ToServantApi sub)) => HasOpenApi (NamedRoutes sub) where
+  toOpenApi _ = toOpenApi (Proxy :: Proxy (ToServantApi sub))
 #endif
 
 -- =======================================================================
diff --git a/src/Servant/OpenApi/Internal/TypeLevel/API.hs b/src/Servant/OpenApi/Internal/TypeLevel/API.hs
--- a/src/Servant/OpenApi/Internal/TypeLevel/API.hs
+++ b/src/Servant/OpenApi/Internal/TypeLevel/API.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                  #-}
 {-# LANGUAGE ConstraintKinds      #-}
 {-# LANGUAGE DataKinds            #-}
 {-# LANGUAGE KindSignatures       #-}
@@ -7,14 +8,19 @@
 {-# LANGUAGE UndecidableInstances #-}
 module Servant.OpenApi.Internal.TypeLevel.API where
 
-import           Data.Type.Bool (If)
-import           GHC.Exts       (Constraint)
+import           GHC.Exts            (Constraint)
 import           Servant.API
+#if MIN_VERSION_servant(0,19,0)
+import           Servant.API.Generic (ToServantApi)
+#endif
 
 -- | Build a list of endpoints from an API.
 type family EndpointsList api where
   EndpointsList (a :<|> b) = AppendList (EndpointsList a) (EndpointsList b)
   EndpointsList (e :> a)   = MapSub e (EndpointsList a)
+#if MIN_VERSION_servant(0,19,0)
+  EndpointsList (NamedRoutes api) = EndpointsList (ToServantApi api)
+#endif
   EndpointsList a = '[a]
 
 -- | Check whether @sub@ is a sub API of @api@.
@@ -43,6 +49,9 @@
 type family IsIn sub api :: Constraint where
   IsIn e (a :<|> b) = Or (IsIn e a) (IsIn e b)
   IsIn (e :> a) (e :> b) = IsIn a b
+#if MIN_VERSION_servant(0,19,0)
+  IsIn e (NamedRoutes api) = IsIn e (ToServantApi api)
+#endif
   IsIn e e = ()
 
 -- | Check whether a type is a member of a list of types.
@@ -83,5 +92,7 @@
   BodyTypes' c (ReqBody' mods cs a :> api) = AddBodyType c cs a (BodyTypes' c api)
   BodyTypes' c (e :> api) = BodyTypes' c api
   BodyTypes' c (a :<|> b) = AppendList (BodyTypes' c a) (BodyTypes' c b)
+#if MIN_VERSION_servant(0,19,0)
+  BodyTypes' c (NamedRoutes api) = BodyTypes' c (ToServantApi api)
+#endif
   BodyTypes' c api = '[]
-