diff --git a/dispatch.go b/dispatch.go
index 75448ee..c90c463 100644
--- a/dispatch.go
+++ b/dispatch.go
@@ -17,8 +17,10 @@ import (
 	sdkv1 "buf.build/gen/go/stealthrocket/dispatch-proto/protocolbuffers/go/dispatch/sdk/v1"
 	"connectrpc.com/connect"
 	"connectrpc.com/validate"
+	"github.com/dispatchrun/dispatch-go/dispatchclient"
 	"github.com/dispatchrun/dispatch-go/dispatchproto"
 	"github.com/dispatchrun/dispatch-go/internal/auth"
+	"github.com/dispatchrun/dispatch-go/internal/env"
 )
 
 // Dispatch is a Dispatch endpoint.
@@ -27,9 +29,9 @@ type Dispatch struct {
 	verificationKey string
 	serveAddr       string
 	env             []string
-	opts            []DispatchOption
+	opts            []Option
 
-	client    *Client
+	client    *dispatchclient.Client
 	clientErr error
 
 	path    string
@@ -39,19 +41,19 @@ type Dispatch struct {
 }
 
 // New creates a Dispatch endpoint.
-func New(opts ...DispatchOption) (*Dispatch, error) {
+func New(opts ...Option) (*Dispatch, error) {
 	d := &Dispatch{
 		env:  os.Environ(),
 		opts: opts,
 	}
 	for _, opt := range opts {
-		opt.configureDispatch(d)
+		opt(d)
 	}
 
 	// Prepare the endpoint URL.
 	var endpointUrlFromEnv bool
 	if d.endpointUrl == "" {
-		d.endpointUrl = getenv(d.env, "DISPATCH_ENDPOINT_URL")
+		d.endpointUrl = env.Get(d.env, "DISPATCH_ENDPOINT_URL")
 		endpointUrlFromEnv = true
 	}
 	if d.endpointUrl == "" {
@@ -67,7 +69,7 @@ func New(opts ...DispatchOption) (*Dispatch, error) {
 
 	// Prepare the address to serve on.
 	if d.serveAddr == "" {
-		d.serveAddr = getenv(d.env, "DISPATCH_ENDPOINT_ADDR")
+		d.serveAddr = env.Get(d.env, "DISPATCH_ENDPOINT_ADDR")
 		if d.serveAddr == "" {
 			d.serveAddr = "127.0.0.1:8000"
 		}
@@ -76,7 +78,7 @@ func New(opts ...DispatchOption) (*Dispatch, error) {
 	// Prepare the verification key.
 	var verificationKeyFromEnv bool
 	if d.verificationKey == "" {
-		d.verificationKey = getenv(d.env, "DISPATCH_VERIFICATION_KEY")
+		d.verificationKey = env.Get(d.env, "DISPATCH_VERIFICATION_KEY")
 		verificationKeyFromEnv = true
 	}
 	var verificationKey ed25519.PublicKey
@@ -111,29 +113,21 @@ func New(opts ...DispatchOption) (*Dispatch, error) {
 
 	// Optionally attach a client.
 	if d.client == nil {
-		d.client, d.clientErr = NewClient(Env(d.env...))
+		d.client, d.clientErr = dispatchclient.New(dispatchclient.Env(d.env...))
 	}
 
 	return d, nil
 }
 
-// DispatchOption configures a Dispatch endpoint.
-type DispatchOption interface {
-	configureDispatch(d *Dispatch)
-}
-
-type dispatchOptionFunc func(d *Dispatch)
-
-func (fn dispatchOptionFunc) configureDispatch(d *Dispatch) {
-	fn(d)
-}
+// Option configures a Dispatch endpoint.
+type Option func(d *Dispatch)
 
 // EndpointUrl sets the URL of the Dispatch endpoint.
 //
 // It defaults to the value of the DISPATCH_ENDPOINT_URL environment
 // variable.
-func EndpointUrl(endpointUrl string) DispatchOption {
-	return dispatchOptionFunc(func(d *Dispatch) { d.endpointUrl = endpointUrl })
+func EndpointUrl(endpointUrl string) Option {
+	return func(d *Dispatch) { d.endpointUrl = endpointUrl }
 }
 
 // VerificationKey sets the verification key to use when verifying
@@ -146,8 +140,8 @@ func EndpointUrl(endpointUrl string) DispatchOption {
 //
 // If a verification key is not provided, request signatures will
 // not be validated.
-func VerificationKey(verificationKey string) DispatchOption {
-	return dispatchOptionFunc(func(d *Dispatch) { d.verificationKey = verificationKey })
+func VerificationKey(verificationKey string) Option {
+	return func(d *Dispatch) { d.verificationKey = verificationKey }
 }
 
 // ServeAddress sets the address that the Dispatch endpoint
@@ -159,8 +153,28 @@ func VerificationKey(verificationKey string) DispatchOption {
 // It defaults to the value of the DISPATCH_ENDPOINT_ADDR environment
 // variable, which is automatically set by the Dispatch CLI. If this
 // is unset, it defaults to 127.0.0.1:8000.
-func ServeAddress(addr string) DispatchOption {
-	return dispatchOptionFunc(func(d *Dispatch) { d.serveAddr = addr })
+func ServeAddress(addr string) Option {
+	return func(d *Dispatch) { d.serveAddr = addr }
+}
+
+// Env sets the environment variables that a Dispatch endpoint
+// parses its default configuration from.
+//
+// It defaults to os.Environ().
+func Env(env ...string) Option {
+	return func(d *Dispatch) { d.env = env }
+}
+
+// Client sets the client to use when dispatching calls
+// from functions registered on the endpoint.
+//
+// By default the Dispatch endpoint will attempt to construct
+// a dispatchclient.Client instance using the DISPATCH_API_KEY
+// and optional DISPATCH_API_URL environment variables. If more
+// control is required over client configuration, the custom
+// client instance can be registered here and used instead.
+func Client(client *dispatchclient.Client) Option {
+	return func(d *Dispatch) { d.client = client }
 }
 
 // Register registers a function.
@@ -185,7 +199,7 @@ func (d *Dispatch) Handler() (string, http.Handler) {
 }
 
 // Client returns the Client attached to this endpoint.
-func (d *Dispatch) Client() (*Client, error) {
+func (d *Dispatch) Client() (*dispatchclient.Client, error) {
 	return d.client, d.clientErr
 }
 
diff --git a/dispatch_test.go b/dispatch_test.go
index 9eb755b..a7ce532 100644
--- a/dispatch_test.go
+++ b/dispatch_test.go
@@ -8,6 +8,7 @@ import (
 
 	"connectrpc.com/connect"
 	"github.com/dispatchrun/dispatch-go"
+	"github.com/dispatchrun/dispatch-go/dispatchclient"
 	"github.com/dispatchrun/dispatch-go/dispatchproto"
 	"github.com/dispatchrun/dispatch-go/dispatchtest"
 )
@@ -76,12 +77,12 @@ func TestDispatchCall(t *testing.T) {
 	recorder := &dispatchtest.CallRecorder{}
 	server := dispatchtest.NewServer(recorder)
 
-	client, err := dispatch.NewClient(dispatch.APIKey("foobar"), dispatch.APIUrl(server.URL))
+	client, err := dispatchclient.New(dispatchclient.APIKey("foobar"), dispatchclient.APIUrl(server.URL))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	endpoint, err := dispatch.New(dispatch.EndpointUrl("http://example.com"), client)
+	endpoint, err := dispatch.New(dispatch.EndpointUrl("http://example.com"), dispatch.Client(client))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -144,12 +145,12 @@ func TestDispatchCallsBatch(t *testing.T) {
 
 	server := dispatchtest.NewServer(&recorder)
 
-	client, err := dispatch.NewClient(dispatch.APIKey("foobar"), dispatch.APIUrl(server.URL))
+	client, err := dispatchclient.New(dispatchclient.APIKey("foobar"), dispatchclient.APIUrl(server.URL))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	endpoint, err := dispatch.New(dispatch.EndpointUrl("http://example.com"), client)
+	endpoint, err := dispatch.New(dispatch.EndpointUrl("http://example.com"), dispatch.Client(client))
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/client.go b/dispatchclient/client.go
similarity index 85%
rename from client.go
rename to dispatchclient/client.go
index a7a6a63..d9112d9 100644
--- a/client.go
+++ b/dispatchclient/client.go
@@ -1,6 +1,4 @@
-//go:build !durable
-
-package dispatch
+package dispatchclient
 
 import (
 	"context"
@@ -14,6 +12,7 @@ import (
 	"connectrpc.com/connect"
 	"connectrpc.com/validate"
 	"github.com/dispatchrun/dispatch-go/dispatchproto"
+	"github.com/dispatchrun/dispatch-go/internal/env"
 )
 
 const defaultApiUrl = "https://api.dispatch.run"
@@ -27,23 +26,23 @@ type Client struct {
 	apiUrl        string
 	env           []string
 	httpClient    *http.Client
-	opts          []ClientOption
+	opts          []Option
 
 	client sdkv1connect.DispatchServiceClient
 }
 
-// NewClient creates a Client.
-func NewClient(opts ...ClientOption) (*Client, error) {
+// New creates a Client.
+func New(opts ...Option) (*Client, error) {
 	c := &Client{
 		env:  os.Environ(),
 		opts: opts,
 	}
 	for _, opt := range opts {
-		opt.configureClient(c)
+		opt(c)
 	}
 
 	if c.apiKey == "" {
-		c.apiKey = getenv(c.env, "DISPATCH_API_KEY")
+		c.apiKey = env.Get(c.env, "DISPATCH_API_KEY")
 		c.apiKeyFromEnv = true
 	}
 	if c.apiKey == "" {
@@ -51,7 +50,7 @@ func NewClient(opts ...ClientOption) (*Client, error) {
 	}
 
 	if c.apiUrl == "" {
-		c.apiUrl = getenv(c.env, "DISPATCH_API_URL")
+		c.apiUrl = env.Get(c.env, "DISPATCH_API_URL")
 	}
 	if c.apiUrl == "" {
 		c.apiUrl = defaultApiUrl
@@ -81,22 +80,14 @@ func NewClient(opts ...ClientOption) (*Client, error) {
 }
 
 // ClientOption configures a Client.
-type ClientOption interface {
-	configureClient(d *Client)
-}
-
-type clientOptionFunc func(d *Client)
-
-func (fn clientOptionFunc) configureClient(d *Client) {
-	fn(d)
-}
+type Option func(*Client)
 
 // APIKey sets the Dispatch API key to use for authentication when
 // dispatching function calls through a Client.
 //
 // It defaults to the value of the DISPATCH_API_KEY environment variable.
-func APIKey(apiKey string) ClientOption {
-	return clientOptionFunc(func(c *Client) { c.apiKey = apiKey })
+func APIKey(apiKey string) Option {
+	return func(c *Client) { c.apiKey = apiKey }
 }
 
 // APIUrl sets the URL of the Dispatch API.
@@ -104,8 +95,16 @@ func APIKey(apiKey string) ClientOption {
 // It defaults to the value of the DISPATCH_API_URL environment variable,
 // or the default API URL (https://api.dispatch.run) if DISPATCH_API_URL
 // is unset.
-func APIUrl(apiUrl string) ClientOption {
-	return clientOptionFunc(func(c *Client) { c.apiUrl = apiUrl })
+func APIUrl(apiUrl string) Option {
+	return func(c *Client) { c.apiUrl = apiUrl }
+}
+
+// Env sets the environment variables that a Client parses its
+// default configuration from.
+//
+// It defaults to os.Environ().
+func Env(env ...string) Option {
+	return func(c *Client) { c.env = env }
 }
 
 // Dispatch dispatches a function call.
@@ -119,10 +118,6 @@ func (c *Client) Dispatch(ctx context.Context, call dispatchproto.Call) (dispatc
 	return ids[0], nil
 }
 
-func (c *Client) configureDispatch(d *Dispatch) {
-	d.client = c
-}
-
 // Batch creates a Batch.
 func (c *Client) Batch() Batch {
 	return Batch{client: c}
diff --git a/client_test.go b/dispatchclient/client_test.go
similarity index 86%
rename from client_test.go
rename to dispatchclient/client_test.go
index 15e2ac8..f025f26 100644
--- a/client_test.go
+++ b/dispatchclient/client_test.go
@@ -1,11 +1,11 @@
-package dispatch_test
+package dispatchclient_test
 
 import (
 	"context"
 	"net/http"
 	"testing"
 
-	"github.com/dispatchrun/dispatch-go"
+	"github.com/dispatchrun/dispatch-go/dispatchclient"
 	"github.com/dispatchrun/dispatch-go/dispatchproto"
 	"github.com/dispatchrun/dispatch-go/dispatchtest"
 )
@@ -14,7 +14,7 @@ func TestClient(t *testing.T) {
 	recorder := &dispatchtest.CallRecorder{}
 	server := dispatchtest.NewServer(recorder)
 
-	client, err := dispatch.NewClient(dispatch.APIKey("foobar"), dispatch.APIUrl(server.URL))
+	client, err := dispatchclient.New(dispatchclient.APIKey("foobar"), dispatchclient.APIUrl(server.URL))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -36,7 +36,7 @@ func TestClientEnvConfig(t *testing.T) {
 	recorder := &dispatchtest.CallRecorder{}
 	server := dispatchtest.NewServer(recorder)
 
-	client, err := dispatch.NewClient(dispatch.Env(
+	client, err := dispatchclient.New(dispatchclient.Env(
 		"DISPATCH_API_KEY=foobar",
 		"DISPATCH_API_URL="+server.URL,
 	))
@@ -61,7 +61,7 @@ func TestClientBatch(t *testing.T) {
 	recorder := &dispatchtest.CallRecorder{}
 	server := dispatchtest.NewServer(recorder)
 
-	client, err := dispatch.NewClient(dispatch.APIKey("foobar"), dispatch.APIUrl(server.URL))
+	client, err := dispatchclient.New(dispatchclient.APIKey("foobar"), dispatchclient.APIUrl(server.URL))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -98,7 +98,7 @@ func TestClientBatch(t *testing.T) {
 }
 
 func TestClientNoAPIKey(t *testing.T) {
-	_, err := dispatch.NewClient(dispatch.Env( /* i.e. no env vars */ ))
+	_, err := dispatchclient.New(dispatchclient.Env( /* i.e. no env vars */ ))
 	if err == nil {
 		t.Fatalf("expected an error")
 	} else if err.Error() != "Dispatch API key has not been set. Use APIKey(..), or set the DISPATCH_API_KEY environment variable" {
diff --git a/dispatchclient/serde.go b/dispatchclient/serde.go
new file mode 100644
index 0000000..bb47225
--- /dev/null
+++ b/dispatchclient/serde.go
@@ -0,0 +1,24 @@
+package dispatchclient
+
+import "github.com/dispatchrun/coroutine/types"
+
+func init() {
+	types.Register(clientSerializer, clientDeserializer)
+}
+
+func clientSerializer(s *types.Serializer, c *Client) error {
+	types.SerializeT(s, c.opts)
+	return nil
+}
+
+func clientDeserializer(d *types.Deserializer, c *Client) error {
+	var opts []Option
+	types.DeserializeTo(d, &opts)
+
+	client, err := New(opts...)
+	if err != nil {
+		return err
+	}
+	*c = *client
+	return nil
+}
diff --git a/dispatchproto/serde.go b/dispatchproto/serde.go
new file mode 100644
index 0000000..4228b39
--- /dev/null
+++ b/dispatchproto/serde.go
@@ -0,0 +1,59 @@
+package dispatchproto
+
+import (
+	"fmt"
+
+	"github.com/dispatchrun/coroutine/types"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/anypb"
+)
+
+func init() {
+	types.Register(protoSerializer, protoDeserializer)
+}
+
+func protoSerializer(s *types.Serializer, mp *proto.Message) error {
+	m := *mp
+	if m == nil {
+		types.SerializeT(s, false)
+		return nil
+	}
+
+	any, err := anypb.New(m)
+	if err != nil {
+		return fmt.Errorf("anypb.New: %w", err)
+	}
+	b, err := proto.Marshal(any)
+	if err != nil {
+		return fmt.Errorf("proto.Marshal: %w", err)
+	}
+
+	types.SerializeT(s, true)
+	types.SerializeT(s, b)
+
+	return nil
+}
+
+func protoDeserializer(d *types.Deserializer, mp *proto.Message) error {
+	var ok bool
+	types.DeserializeTo(d, &ok)
+	if !ok {
+		*mp = nil
+		return nil
+	}
+
+	var b []byte
+	types.DeserializeTo(d, &b)
+
+	var any anypb.Any
+	if err := proto.Unmarshal(b, &any); err != nil {
+		return fmt.Errorf("proto.Unmarshal: %w", err)
+	}
+	m, err := any.UnmarshalNew()
+	if err != nil {
+		return fmt.Errorf("anypb.UnmarshalNew: %w", err)
+	}
+	*mp = m
+
+	return nil
+}
diff --git a/dispatchtest/endpoint.go b/dispatchtest/endpoint.go
index 8c9e420..99b2b6c 100644
--- a/dispatchtest/endpoint.go
+++ b/dispatchtest/endpoint.go
@@ -15,7 +15,7 @@ import (
 //
 // Unlike dispatch.New, it starts a test server that serves the endpoint
 // and automatically sets the endpoint URL.
-func NewEndpoint(opts ...dispatch.DispatchOption) (*dispatch.Dispatch, *EndpointServer, error) {
+func NewEndpoint(opts ...dispatch.Option) (*dispatch.Dispatch, *EndpointServer, error) {
 	mux := http.NewServeMux()
 	server := httptest.NewServer(mux)
 
diff --git a/env.go b/env.go
deleted file mode 100644
index 044737c..0000000
--- a/env.go
+++ /dev/null
@@ -1,35 +0,0 @@
-//go:build !durable
-
-package dispatch
-
-import (
-	"slices"
-	"strings"
-)
-
-// Env sets the environment variables that a Dispatch endpoint
-// or Client parses its default configuration from.
-//
-// It defaults to os.Environ().
-func Env(env ...string) interface {
-	DispatchOption
-	ClientOption
-} {
-	return envOption(env)
-}
-
-type envOption []string
-
-func (env envOption) configureDispatch(d *Dispatch) { d.env = slices.Clone(env) }
-func (env envOption) configureClient(c *Client)     { c.env = slices.Clone(env) }
-
-func getenv(env []string, name string) string {
-	var value string
-	for _, s := range env {
-		n, v, ok := strings.Cut(s, "=")
-		if ok && n == name {
-			value = v
-		}
-	}
-	return value
-}
diff --git a/internal/env/env.go b/internal/env/env.go
new file mode 100644
index 0000000..b240568
--- /dev/null
+++ b/internal/env/env.go
@@ -0,0 +1,15 @@
+package env
+
+import "strings"
+
+// Get gets an environment variable value from a set of environment variables.
+func Get(env []string, name string) string {
+	var value string
+	for _, s := range env {
+		n, v, ok := strings.Cut(s, "=")
+		if ok && n == name {
+			value = v
+		}
+	}
+	return value
+}
diff --git a/serde.go b/serde.go
index cd2d98d..6682641 100644
--- a/serde.go
+++ b/serde.go
@@ -2,68 +2,14 @@
 
 package dispatch
 
-import (
-	"fmt"
-
-	"github.com/dispatchrun/coroutine/types"
-	"google.golang.org/protobuf/proto"
-	"google.golang.org/protobuf/types/known/anypb"
-)
+import "github.com/dispatchrun/coroutine/types"
 
 func init() {
-	types.Register(protoSerializer, protoDeserializer)
 	types.Register(dispatchSerializer, dispatchDeserializer)
-	types.Register(clientSerializer, clientDeserializer)
-}
-
-func protoSerializer(s *types.Serializer, mp *proto.Message) error {
-	m := *mp
-	if m == nil {
-		types.SerializeT(s, false)
-		return nil
-	}
-
-	any, err := anypb.New(m)
-	if err != nil {
-		return fmt.Errorf("anypb.New: %w", err)
-	}
-	b, err := proto.Marshal(any)
-	if err != nil {
-		return fmt.Errorf("proto.Marshal: %w", err)
-	}
-
-	types.SerializeT(s, true)
-	types.SerializeT(s, b)
-
-	return nil
-}
-
-func protoDeserializer(d *types.Deserializer, mp *proto.Message) error {
-	var ok bool
-	types.DeserializeTo(d, &ok)
-	if !ok {
-		*mp = nil
-		return nil
-	}
-
-	var b []byte
-	types.DeserializeTo(d, &b)
-
-	var any anypb.Any
-	if err := proto.Unmarshal(b, &any); err != nil {
-		return fmt.Errorf("proto.Unmarshal: %w", err)
-	}
-	m, err := any.UnmarshalNew()
-	if err != nil {
-		return fmt.Errorf("anypb.UnmarshalNew: %w", err)
-	}
-	*mp = m
-
-	return nil
 }
 
 type serializedDispatch struct {
-	opts      []DispatchOption
+	opts      []Option
 	functions *FunctionRegistry
 }
 
@@ -84,20 +30,3 @@ func dispatchDeserializer(d *types.Deserializer, c *Dispatch) error {
 	*c = *dispatch                     //nolint
 	return nil
 }
-
-func clientSerializer(s *types.Serializer, c *Client) error {
-	types.SerializeT(s, c.opts)
-	return nil
-}
-
-func clientDeserializer(d *types.Deserializer, c *Client) error {
-	var opts []ClientOption
-	types.DeserializeTo(d, &opts)
-
-	client, err := NewClient(opts...)
-	if err != nil {
-		return err
-	}
-	*c = *client
-	return nil
-}