diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6ad7112..4ae5551 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,12 @@ The format is based on [Keep a Changelog], and this project adheres to
 [keep a changelog]: https://keepachangelog.com/en/1.0.0/
 [semantic versioning]: https://semver.org/spec/v2.0.0.html
 
+## [0.8.2] - 2023-04-26
+
+### Changed
+
+- Change `WithRoute()` to accept unmarshaling options
+
 ## [0.8.1] - 2023-04-25
 
 ### Added
@@ -150,6 +156,10 @@ if err != nil {
 [0.6.0]: https://github.com/dogmatiq/harpy/releases/tag/v0.6.0
 [0.6.1]: https://github.com/dogmatiq/harpy/releases/tag/v0.6.1
 [0.6.2]: https://github.com/dogmatiq/harpy/releases/tag/v0.6.2
+[0.7.0]: https://github.com/dogmatiq/harpy/releases/tag/v0.7.0
+[0.8.0]: https://github.com/dogmatiq/harpy/releases/tag/v0.8.0
+[0.8.1]: https://github.com/dogmatiq/harpy/releases/tag/v0.8.1
+[0.8.2]: https://github.com/dogmatiq/harpy/releases/tag/v0.8.2
 
 <!-- version template
 ## [0.0.1] - YYYY-MM-DD
diff --git a/internal/jsonx/unmarshal.go b/internal/jsonx/unmarshal.go
index 53a2b2d..0df932d 100644
--- a/internal/jsonx/unmarshal.go
+++ b/internal/jsonx/unmarshal.go
@@ -7,11 +7,7 @@ import (
 )
 
 // Decode unmarshals JSON content from r into v.
-func Decode[O ~UnmarshalOption](
-	r io.Reader,
-	v any,
-	options ...O,
-) error {
+func Decode(r io.Reader, v any, options ...UnmarshalOption) error {
 	var opts UnmarshalOptions
 	for _, fn := range options {
 		fn(&opts)
@@ -26,11 +22,7 @@ func Decode[O ~UnmarshalOption](
 }
 
 // Unmarshal unmarshals JSON content from data into v.
-func Unmarshal[O ~UnmarshalOption](
-	data []byte,
-	v any,
-	options ...O,
-) error {
+func Unmarshal(data []byte, v any, options ...UnmarshalOption) error {
 	return Decode(
 		bytes.NewReader(data),
 		v,
@@ -38,10 +30,10 @@ func Unmarshal[O ~UnmarshalOption](
 	)
 }
 
+// UnmarshalOption is an option that changes the behavior of JSON unmarshaling.
+type UnmarshalOption func(*UnmarshalOptions)
+
 // UnmarshalOptions is a set of options that control how JSON is unmarshaled.
 type UnmarshalOptions struct {
 	AllowUnknownFields bool
 }
-
-// UnmarshalOption is a function that changes the behavior of JSON unmarshaling.
-type UnmarshalOption = func(*UnmarshalOptions)
diff --git a/json.go b/json.go
index 8279ed3..2fd187b 100644
--- a/json.go
+++ b/json.go
@@ -5,7 +5,7 @@ import (
 )
 
 // UnmarshalOption is an option that changes the behavior of JSON unmarshaling.
-type UnmarshalOption func(*jsonx.UnmarshalOptions)
+type UnmarshalOption = jsonx.UnmarshalOption
 
 // AllowUnknownFields is an UnmarshalOption that controls whether parameters,
 // results and error data may contain unknown fields.
diff --git a/request.go b/request.go
index c8dc9ba..a3e5f23 100644
--- a/request.go
+++ b/request.go
@@ -364,7 +364,7 @@ func unmarshalBatchRequest(r *bufio.Reader) (RequestSet, error) {
 // unmarshalJSONForRequest unmarshals JSON content from r into v. If the JSON
 // cannot be parsed it returns a JSON-RPC error with the "parse error" code.
 func unmarshalJSONForRequest(r io.Reader, v any) error {
-	err := jsonx.Decode[jsonx.UnmarshalOption](r, v)
+	err := jsonx.Decode(r, v)
 
 	if jsonx.IsParseError(err) {
 		return NewErrorWithReservedCode(
diff --git a/response.go b/response.go
index da168aa..0deca26 100644
--- a/response.go
+++ b/response.go
@@ -355,7 +355,7 @@ func unmarshalBatchResponse(r *bufio.Reader) (ResponseSet, error) {
 
 // unmarshalJSONForResponse unmarshals JSON content from r into v.
 func unmarshalJSONForResponse(r io.Reader, v any) error {
-	err := jsonx.Decode[jsonx.UnmarshalOption](r, v)
+	err := jsonx.Decode(r, v)
 
 	if jsonx.IsParseError(err) {
 		return fmt.Errorf("unable to parse response: %w", err)
diff --git a/router.go b/router.go
index 1f1788c..c4f5263 100644
--- a/router.go
+++ b/router.go
@@ -71,12 +71,13 @@ type RouterOption func(*Router)
 func WithRoute[P, R any](
 	m string,
 	h func(context.Context, P) (R, error),
+	options ...UnmarshalOption,
 ) RouterOption {
 	return WithUntypedRoute(
 		m,
 		func(ctx context.Context, req Request) (any, error) {
 			var params P
-			if err := req.UnmarshalParameters(&params); err != nil {
+			if err := req.UnmarshalParameters(&params, options...); err != nil {
 				return nil, err
 			}
 
diff --git a/router_test.go b/router_test.go
index 61ee0df..1b71c2f 100644
--- a/router_test.go
+++ b/router_test.go
@@ -43,6 +43,30 @@ var _ = Describe("type Router", func() {
 			Expect(called).To(BeTrue())
 		})
 
+		It("supports unmarshal options (via WithRoute())", func() {
+			called := false
+			request.Parameters = json.RawMessage(`{"Value": 123, "Unknown": 456}`)
+
+			type Params struct {
+				Value int
+			}
+
+			router = NewRouter(
+				WithRoute(
+					"<method>",
+					func(ctx context.Context, params Params) (any, error) {
+						called = true
+						Expect(params).To(Equal(Params{Value: 123}))
+						return nil, nil
+					},
+					AllowUnknownFields(true),
+				),
+			)
+
+			router.Call(context.Background(), request)
+			Expect(called).To(BeTrue())
+		})
+
 		It("allows calls to handlers that don't return a result (via NoResult())", func() {
 			called := false