diff --git a/_examples/queues/.gitignore b/_examples/queues/.gitignore
new file mode 100644
index 0000000..aee7b7e
--- /dev/null
+++ b/_examples/queues/.gitignore
@@ -0,0 +1,3 @@
+build
+node_modules
+.wrangler
diff --git a/_examples/queues/Makefile b/_examples/queues/Makefile
new file mode 100644
index 0000000..db68197
--- /dev/null
+++ b/_examples/queues/Makefile
@@ -0,0 +1,12 @@
+.PHONY: dev
+dev:
+	npx wrangler dev --port 8787
+
+.PHONY: build
+build:
+	go run ../../cmd/workers-assets-gen
+	tinygo build -o ./build/app.wasm -target wasm -no-debug ./...
+
+.PHONY: deploy
+deploy:
+	npx wrangler deploy
diff --git a/_examples/queues/README.md b/_examples/queues/README.md
new file mode 100644
index 0000000..cfb6ef9
--- /dev/null
+++ b/_examples/queues/README.md
@@ -0,0 +1,38 @@
+# queues
+
+An example of using Cloudflare Workers that interact with [Cloudflare Queues](https://developers.cloudflare.com/queues/).
+
+## Running
+
+### Requirements
+
+This project requires these tools to be installed globally.
+
+* wrangler
+* tinygo
+
+### Supported commands
+
+```
+make dev     # run dev server
+make build   # build Go Wasm binary
+make deploy # deploy worker
+```
+
+### Interacting with the local queue
+
+1. Start the dev server.
+```sh
+make dev
+```
+
+2. Send a message to the queue.
+```sh
+curl -v -X POST http://localhost:8787/ -d '{"message": "Hello, World!"}' -H "Content-Type: application/json"
+```
+
+3. Observe the response and server logs
+
+4. You can pass `text/plain` content type to write queue message as the string or omit the `Content-Type` header to write queue message as 
+byte array.
+
diff --git a/_examples/queues/go.mod b/_examples/queues/go.mod
new file mode 100644
index 0000000..779f83b
--- /dev/null
+++ b/_examples/queues/go.mod
@@ -0,0 +1,7 @@
+module github.com/syumai/workers/_examples/queues
+
+go 1.22.8
+
+require github.com/syumai/workers v0.0.0
+
+replace github.com/syumai/workers => ../../
diff --git a/_examples/queues/go.sum b/_examples/queues/go.sum
new file mode 100644
index 0000000..e69de29
diff --git a/_examples/queues/main.go b/_examples/queues/main.go
new file mode 100644
index 0000000..c899b15
--- /dev/null
+++ b/_examples/queues/main.go
@@ -0,0 +1,105 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/syumai/workers"
+	"github.com/syumai/workers/cloudflare/queues"
+)
+
+const queueName = "QUEUE"
+
+func handleErr(w http.ResponseWriter, msg string, err error) {
+	log.Println(err)
+	w.WriteHeader(http.StatusInternalServerError)
+	w.Write([]byte(msg))
+}
+
+func main() {
+	http.HandleFunc("/", handleProduce)
+	workers.Serve(nil)
+}
+func handleProduce(w http.ResponseWriter, req *http.Request) {
+	if req.URL.Path != "/" {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	if req.Method != http.MethodPost {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+
+	defer req.Body.Close()
+
+	q, err := queues.NewProducer(queueName)
+	if err != nil {
+		handleErr(w, "failed to init queue", err)
+	}
+
+	contentType := req.Header.Get("Content-Type")
+	switch contentType {
+	case "text/plain":
+		log.Println("Handling text content type")
+		err = produceText(q, req)
+	case "application/json":
+		log.Println("Handling json content type")
+		err = produceJson(q, req)
+	default:
+		log.Println("Handling bytes content type")
+		err = produceBytes(q, req)
+	}
+
+	if err != nil {
+		handleErr(w, "failed to handle request", err)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("message sent\n"))
+}
+
+func produceText(q *queues.Producer, req *http.Request) error {
+	content, err := io.ReadAll(req.Body)
+	if err != nil {
+		return fmt.Errorf("failed to read request body: %w", err)
+	}
+	if len(content) == 0 {
+		return fmt.Errorf("empty request body")
+	}
+
+	// text content type supports string and []byte messages
+	if err := q.Send(content, queues.WithContentType(queues.QueueContentTypeText)); err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+
+	return nil
+}
+
+func produceJson(q *queues.Producer, req *http.Request) error {
+	var data any
+	if err := json.NewDecoder(req.Body).Decode(&data); err != nil {
+		return fmt.Errorf("failed to read request body: %w", err)
+	}
+
+	// json content type is default and therefore can be omitted
+	// json content type supports messages of types that can be serialized to json
+	if err := q.Send(data); err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+
+	return nil
+}
+
+func produceBytes(q *queues.Producer, req *http.Request) error {
+	// bytes content type support messages of type []byte, string, and io.Reader
+	if err := q.Send(req.Body, queues.WithContentType(queues.QueueContentTypeBytes)); err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+
+	return nil
+}
diff --git a/_examples/queues/wrangler.toml b/_examples/queues/wrangler.toml
new file mode 100644
index 0000000..0965832
--- /dev/null
+++ b/_examples/queues/wrangler.toml
@@ -0,0 +1,13 @@
+name = "queues-producer"
+main = "./build/worker.mjs"
+compatibility_date = "2022-05-13"
+compatibility_flags = [
+    "streams_enable_constructors"
+]
+
+[[queues.producers]]
+queue = "my-queue"
+binding = "QUEUE"
+
+[build]
+command = "make build"
diff --git a/cloudflare/queues/content_type.go b/cloudflare/queues/content_type.go
new file mode 100644
index 0000000..b0db97a
--- /dev/null
+++ b/cloudflare/queues/content_type.go
@@ -0,0 +1,82 @@
+package queues
+
+import (
+	"fmt"
+	"io"
+	"syscall/js"
+
+	"github.com/syumai/workers/internal/jsutil"
+)
+
+// QueueContentType represents the content type of a message produced to a queue.
+// This information mostly affects how the message body is represented in the Cloudflare UI and is NOT
+// propagated to the consumer side.
+//   - https://developers.cloudflare.com/queues/configuration/javascript-apis/#queuescontenttype
+type QueueContentType string
+
+const (
+	// QueueContentTypeJSON is the default content type for the produced queue message.
+	// The message body is NOT being marshaled before sending and is passed to js.ValueOf directly.
+	// Make sure the body is serializable to JSON.
+	//  - https://pkg.go.dev/syscall/js#ValueOf
+	QueueContentTypeJSON QueueContentType = "json"
+
+	// QueueContentTypeV8 is currently treated the same as QueueContentTypeJSON.
+	QueueContentTypeV8 QueueContentType = "v8"
+
+	// QueueContentTypeText is used to send a message as a string.
+	// Supported body types are string, []byte and io.Reader.
+	QueueContentTypeText QueueContentType = "text"
+
+	// QueueContentTypeBytes is used to send a message as a byte array.
+	// Supported body types are string, []byte, and io.Reader.
+	QueueContentTypeBytes QueueContentType = "bytes"
+)
+
+func (o QueueContentType) mapValue(val any) (js.Value, error) {
+	switch o {
+	case QueueContentTypeText:
+		switch v := val.(type) {
+		case string:
+			return js.ValueOf(v), nil
+		case []byte:
+			return js.ValueOf(string(v)), nil
+		case io.Reader:
+			b, err := io.ReadAll(v)
+			if err != nil {
+				return js.Undefined(), fmt.Errorf("failed to read bytes from reader: %w", err)
+			}
+			return js.ValueOf(string(b)), nil
+		default:
+			return js.Undefined(), fmt.Errorf("invalid value type for text content type: %T", val)
+		}
+
+	case QueueContentTypeBytes:
+		var b []byte
+		switch v := val.(type) {
+		case string:
+			b = []byte(v)
+		case []byte:
+			b = v
+		case io.Reader:
+			var err error
+			b, err = io.ReadAll(v)
+			if err != nil {
+				return js.Undefined(), fmt.Errorf("failed to read bytes from reader: %w", err)
+			}
+		default:
+			return js.Undefined(), fmt.Errorf("invalid value type for bytes content type: %T", val)
+		}
+
+		ua := jsutil.NewUint8Array(len(b))
+		js.CopyBytesToJS(ua, b)
+		// accortind to docs, "bytes" type requires an ArrayBuffer to be sent, however practical experience shows that ArrayBufferView should
+		// be used instead and with Uint8Array.buffer as a value, the send simply fails
+		return ua, nil
+
+	case QueueContentTypeJSON, QueueContentTypeV8:
+		return js.ValueOf(val), nil
+	}
+
+	return js.Undefined(), fmt.Errorf("unknown content type: %s", o)
+}
diff --git a/cloudflare/queues/content_type_test.go b/cloudflare/queues/content_type_test.go
new file mode 100644
index 0000000..5305c97
--- /dev/null
+++ b/cloudflare/queues/content_type_test.go
@@ -0,0 +1,205 @@
+package queues
+
+import (
+	"bytes"
+	"syscall/js"
+	"testing"
+
+	"github.com/syumai/workers/internal/jsutil"
+)
+
+func TestContentType_mapValue(t *testing.T) {
+	tests := []struct {
+		name        string
+		contentType QueueContentType
+		val         any
+		want        js.Value
+		wantErr     bool
+	}{
+		{
+			name:        "string as text",
+			contentType: QueueContentTypeText,
+			val:         "hello",
+			want:        js.ValueOf("hello"),
+		},
+		{
+			name:        "[]byte as text",
+			contentType: QueueContentTypeText,
+			val:         []byte("hello"),
+			want:        js.ValueOf("hello"),
+		},
+		{
+			name:        "io.Reader as text",
+			contentType: QueueContentTypeText,
+			val:         bytes.NewBufferString("hello"),
+			want:        js.ValueOf("hello"),
+		},
+		{
+			name:        "number as text",
+			contentType: QueueContentTypeText,
+			val:         42,
+			want:        js.Undefined(),
+			wantErr:     true,
+		},
+		{
+			name:        "function as text",
+			contentType: QueueContentTypeText,
+			val:         func() {},
+			want:        js.Undefined(),
+			wantErr:     true,
+		},
+
+		{
+			name:        "string as json",
+			contentType: QueueContentTypeJSON,
+			val:         "hello",
+			want:        js.ValueOf("hello"),
+		},
+		{
+			name:        "number as json",
+			contentType: QueueContentTypeJSON,
+			val:         42,
+			want:        js.ValueOf(42),
+		},
+		{
+			name:        "bool as json",
+			contentType: QueueContentTypeJSON,
+			val:         true,
+			want:        js.ValueOf(true),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := tt.contentType.mapValue(tt.val)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("%s.mapValue() error = %v, wantErr %v", tt.contentType, err, tt.wantErr)
+			}
+			if got.String() != tt.want.String() {
+				t.Errorf("%s.mapValue() = %v, want %v", tt.contentType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestContentType_mapValue_bytes(t *testing.T) {
+	jsOf := func(b []byte) js.Value {
+		ua := jsutil.NewUint8Array(len(b))
+		js.CopyBytesToJS(ua, b)
+		return ua
+	}
+
+	tests := []struct {
+		name string
+		val  any
+		want js.Value
+	}{
+		{
+			name: "[]byte as bytes",
+			val:  []byte("hello"),
+			want: jsOf([]byte("hello")),
+		},
+		{
+			name: "string as bytes",
+			val:  "hello",
+			want: jsOf([]byte("hello"))},
+		{
+			name: "io.Reader as bytes",
+			val:  bytes.NewBufferString("hello"),
+			want: jsOf([]byte("hello")),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := QueueContentTypeBytes.mapValue(tt.val)
+			if err != nil {
+				t.Fatalf("%s.mapValue() got error = %v", QueueContentTypeBytes, err)
+			}
+			if got.Type() != tt.want.Type() {
+				t.Errorf("%s.mapValue() = type %v, want type %v", QueueContentTypeBytes, got, tt.want)
+			}
+			if got.String() != tt.want.String() {
+				t.Errorf("%s.mapValue() = %v, want %v", QueueContentTypeBytes, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestContentType_mapValue_map(t *testing.T) {
+	val := map[string]interface{}{
+		"Name": "Alice",
+		"Age":  42,
+	}
+
+	tests := []struct {
+		name        string
+		contentType QueueContentType
+	}{
+		{
+			name:        "json",
+			contentType: QueueContentTypeJSON,
+		},
+		{
+			name:        "v8",
+			contentType: QueueContentTypeV8,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+
+			got, err := tt.contentType.mapValue(val)
+			if err != nil {
+				t.Fatalf("QueueContentTypeJSON.mapValue() got error = %v", err)
+			}
+			if got.Type() != js.TypeObject {
+				t.Errorf("QueueContentTypeJSON.mapValue() = type %v, want type %v", got, js.TypeObject)
+			}
+			if got.Get("Name").String() != "Alice" {
+				t.Errorf("QueueContentTypeJSON.mapValue() = %v, want %v", got.Get("Name").String(), "Alice")
+			}
+			if got.Get("Age").Int() != 42 {
+				t.Errorf("QueueContentTypeJSON.mapValue() = %v, want %v", got.Get("Age").Int(), 42)
+			}
+		})
+	}
+}
+
+type User struct {
+	Name string
+}
+
+func TestContentType_mapValue_unsupported_types(t *testing.T) {
+	t.Run("struct as json", func(t *testing.T) {
+		defer func() {
+			if p := recover(); p == nil {
+				t.Fatalf("QueueContentTypeJSON.mapValue() did not panic")
+			}
+		}()
+
+		val := User{Name: "Alice"}
+		_, _ = QueueContentTypeJSON.mapValue(val)
+	})
+
+	t.Run("slice of structs as json", func(t *testing.T) {
+		defer func() {
+			if p := recover(); p == nil {
+				t.Fatalf("QueueContentTypeJSON.mapValue() did not panic")
+			}
+		}()
+
+		val := User{Name: "Alice"}
+		_, _ = QueueContentTypeJSON.mapValue([]User{val})
+	})
+
+	t.Run("slice of bytes as json", func(t *testing.T) {
+		defer func() {
+			if p := recover(); p == nil {
+				t.Fatalf("QueueContentTypeJSON.mapValue() did not panic")
+			}
+		}()
+
+		_, _ = QueueContentTypeJSON.mapValue([]byte("hello"))
+	})
+}
diff --git a/cloudflare/queues/producer.go b/cloudflare/queues/producer.go
new file mode 100644
index 0000000..6fa47eb
--- /dev/null
+++ b/cloudflare/queues/producer.go
@@ -0,0 +1,115 @@
+package queues
+
+import (
+	"errors"
+	"fmt"
+	"syscall/js"
+
+	"github.com/syumai/workers/cloudflare/internal/cfruntimecontext"
+	"github.com/syumai/workers/internal/jsutil"
+)
+
+type BatchMessage struct {
+	body    any
+	options *sendOptions
+}
+
+// NewBatchMessage creates a single message to be batched before sending to a queue.
+func NewBatchMessage(body any, opts ...SendOption) *BatchMessage {
+	options := defaultSendOptions()
+	for _, opt := range opts {
+		opt(options)
+	}
+	return &BatchMessage{body: body, options: options}
+}
+
+func (m *BatchMessage) toJS() (js.Value, error) {
+	if m == nil {
+		return js.Undefined(), errors.New("message is nil")
+	}
+
+	jsValue, err := m.options.ContentType.mapValue(m.body)
+	if err != nil {
+		return js.Undefined(), err
+	}
+
+	obj := jsutil.NewObject()
+	obj.Set("body", jsValue)
+	obj.Set("options", m.options.toJS())
+
+	return obj, nil
+}
+
+type Producer struct {
+	// queue - Objects that Queue API belongs to. Default is Global
+	queue js.Value
+}
+
+// NewProducer creates a new Producer object to send messages to a queue.
+// queueName is the name of the queue environment var to send messages to.
+// In Cloudflare API documentation, this object represents the Queue.
+//   - https://developers.cloudflare.com/queues/configuration/javascript-apis/#producer
+func NewProducer(queueName string) (*Producer, error) {
+	inst := cfruntimecontext.MustGetRuntimeContextEnv().Get(queueName)
+	if inst.IsUndefined() {
+		return nil, fmt.Errorf("%s is undefined", queueName)
+	}
+	return &Producer{queue: inst}, nil
+}
+
+// Send sends a single message to a queue. This function allows setting send options for the message.
+// If no options are provided, the default options are used (QueueContentTypeJSON and no delay).
+//
+//   - https://developers.cloudflare.com/queues/configuration/javascript-apis/#producer
+//   - https://developers.cloudflare.com/queues/configuration/javascript-apis/#queuesendoptions
+func (p *Producer) Send(content any, opts ...SendOption) error {
+	if p.queue.IsUndefined() {
+		return errors.New("queue object not found")
+	}
+
+	options := defaultSendOptions()
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	jsValue, err := options.ContentType.mapValue(content)
+	if err != nil {
+		return err
+	}
+
+	prom := p.queue.Call("send", jsValue, options.toJS())
+	_, err = jsutil.AwaitPromise(prom)
+	return err
+}
+
+// SendBatch sends multiple messages to a queue. This function allows setting options for	each message.
+func (p *Producer) SendBatch(messages []*BatchMessage, opts ...BatchSendOption) error {
+	if p.queue.IsUndefined() {
+		return errors.New("queue object not found")
+	}
+
+	if len(messages) == 0 {
+		return nil
+	}
+
+	var options *batchSendOptions
+	if len(opts) > 0 {
+		options = &batchSendOptions{}
+		for _, opt := range opts {
+			opt(options)
+		}
+	}
+
+	jsArray := jsutil.NewArray(len(messages))
+	for i, message := range messages {
+		jsValue, err := message.toJS()
+		if err != nil {
+			return fmt.Errorf("failed to convert message %d to JS: %w", i, err)
+		}
+		jsArray.SetIndex(i, jsValue)
+	}
+
+	prom := p.queue.Call("sendBatch", jsArray, options.toJS())
+	_, err := jsutil.AwaitPromise(prom)
+	return err
+}
diff --git a/cloudflare/queues/producer_opts.go b/cloudflare/queues/producer_opts.go
new file mode 100644
index 0000000..5d345ae
--- /dev/null
+++ b/cloudflare/queues/producer_opts.go
@@ -0,0 +1,79 @@
+package queues
+
+import (
+	"syscall/js"
+	"time"
+
+	"github.com/syumai/workers/internal/jsutil"
+)
+
+type sendOptions struct {
+	// ContentType - Content type of the message
+	// Default is "json"
+	ContentType QueueContentType
+
+	// DelaySeconds - The number of seconds to delay the message.
+	// Default is 0
+	DelaySeconds int
+}
+
+func defaultSendOptions() *sendOptions {
+	return &sendOptions{
+		ContentType: QueueContentTypeJSON,
+	}
+}
+
+func (o *sendOptions) toJS() js.Value {
+	obj := jsutil.NewObject()
+	obj.Set("contentType", string(o.ContentType))
+
+	if o.DelaySeconds != 0 {
+		obj.Set("delaySeconds", o.DelaySeconds)
+	}
+
+	return obj
+}
+
+type SendOption func(*sendOptions)
+
+// WithContentType changes the content type of the message.
+func WithContentType(contentType QueueContentType) SendOption {
+	return func(o *sendOptions) {
+		o.ContentType = contentType
+	}
+}
+
+// WithDelay changes the number of seconds to delay the message.
+func WithDelay(d time.Duration) SendOption {
+	return func(o *sendOptions) {
+		o.DelaySeconds = int(d.Seconds())
+	}
+}
+
+type batchSendOptions struct {
+	// DelaySeconds - The number of seconds to delay the message.
+	// Default is 0
+	DelaySeconds int
+}
+
+func (o *batchSendOptions) toJS() js.Value {
+	if o == nil {
+		return js.Undefined()
+	}
+
+	obj := jsutil.NewObject()
+	if o.DelaySeconds != 0 {
+		obj.Set("delaySeconds", o.DelaySeconds)
+	}
+
+	return obj
+}
+
+type BatchSendOption func(*batchSendOptions)
+
+// WithBatchDelay changes the number of seconds to delay the message.
+func WithBatchDelay(d time.Duration) BatchSendOption {
+	return func(o *batchSendOptions) {
+		o.DelaySeconds = int(d.Seconds())
+	}
+}
diff --git a/cloudflare/queues/producer_test.go b/cloudflare/queues/producer_test.go
new file mode 100644
index 0000000..fc00a93
--- /dev/null
+++ b/cloudflare/queues/producer_test.go
@@ -0,0 +1,211 @@
+package queues
+
+import (
+	"errors"
+	"fmt"
+	"syscall/js"
+	"testing"
+	"time"
+
+	"github.com/syumai/workers/internal/jsutil"
+)
+
+func validatingProducer(t *testing.T, validateFn func(message js.Value, options js.Value) error) *Producer {
+	sendFn := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		sendArg := args[0] // this should be batch (in case of SendBatch) or a single message (in case of Send)
+		var options js.Value
+		if len(args) > 1 {
+			options = args[1]
+		}
+		return jsutil.NewPromise(js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+			resolve := args[0]
+			go func() {
+				if err := validateFn(sendArg, options); err != nil {
+					// must be non-fatal to avoid a deadlock
+					t.Errorf("validation failed: %v", err)
+				}
+				resolve.Invoke(js.Undefined())
+			}()
+			return js.Undefined()
+		}))
+	})
+
+	queue := jsutil.NewObject()
+	queue.Set("send", sendFn)
+	queue.Set("sendBatch", sendFn)
+
+	return &Producer{queue: queue}
+}
+
+func TestSend(t *testing.T) {
+	t.Run("text content type", func(t *testing.T) {
+		validation := func(message js.Value, options js.Value) error {
+			if message.Type() != js.TypeString {
+				return errors.New("message body must be a string")
+			}
+			if message.String() != "hello" {
+				return errors.New("message body must be 'hello'")
+			}
+			if options.Get("contentType").String() != "text" {
+				return errors.New("content type must be text")
+			}
+			return nil
+		}
+
+		producer := validatingProducer(t, validation)
+		err := producer.Send("hello", WithContentType(QueueContentTypeText))
+		if err != nil {
+			t.Fatalf("Send failed: %v", err)
+		}
+	})
+
+	t.Run("json content type", func(t *testing.T) {
+		validation := func(message js.Value, options js.Value) error {
+			if message.Type() != js.TypeString {
+				return errors.New("message body must be a string")
+			}
+			if message.String() != "hello" {
+				return errors.New("message body must be 'hello'")
+			}
+			if options.Get("contentType").String() != "json" {
+				return errors.New("content type must be json")
+			}
+			return nil
+		}
+
+		producer := validatingProducer(t, validation)
+		err := producer.Send("hello", WithContentType(QueueContentTypeJSON))
+		if err != nil {
+			t.Fatalf("Send failed: %v", err)
+		}
+	})
+}
+
+func TestSend_ContentTypeOption(t *testing.T) {
+	tests := []struct {
+		name                string
+		options             []SendOption
+		expectedContentType string
+		expectedDelaySec    int
+		wantErr             bool
+	}{
+		{
+			name:                "text",
+			options:             []SendOption{WithContentType(QueueContentTypeText)},
+			expectedContentType: "text",
+		},
+		{
+			name:                "json",
+			options:             []SendOption{WithContentType(QueueContentTypeJSON)},
+			expectedContentType: "json",
+		},
+		{
+			name:                "default",
+			options:             nil,
+			expectedContentType: "json",
+		},
+		{
+			name:                "v8",
+			options:             []SendOption{WithContentType(QueueContentTypeV8)},
+			expectedContentType: "v8",
+		},
+		{
+			name:                "bytes",
+			options:             []SendOption{WithContentType(QueueContentTypeBytes)},
+			expectedContentType: "bytes",
+		},
+
+		{
+			name:                "delay",
+			options:             []SendOption{WithDelay(5 * time.Second)},
+			expectedDelaySec:    5,
+			expectedContentType: "json",
+		},
+
+		{
+			name:    "invalid content type",
+			options: []SendOption{WithContentType("invalid")},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			validation := func(message js.Value, options js.Value) error {
+				gotCT := options.Get("contentType").String()
+				if gotCT != string(tt.expectedContentType) {
+					return fmt.Errorf("expected content type %q, got %q", tt.expectedContentType, gotCT)
+				}
+				gotDelaySec := jsutil.MaybeInt(options.Get("delaySeconds"))
+				if gotDelaySec != tt.expectedDelaySec {
+					return fmt.Errorf("expected delay %d, got %d", tt.expectedDelaySec, gotDelaySec)
+				}
+				return nil
+			}
+
+			producer := validatingProducer(t, validation)
+			err := producer.Send("hello", tt.options...)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("expected error: %t, got %v", tt.wantErr, err)
+			}
+		})
+	}
+}
+
+func TestSendBatch_Defaults(t *testing.T) {
+	validation := func(batch js.Value, options js.Value) error {
+		if batch.Type() != js.TypeObject {
+			return errors.New("message batch must be an object (array)")
+		}
+		if batch.Length() != 2 {
+			return fmt.Errorf("expected 2 messages, got %d", batch.Length())
+		}
+		first := batch.Index(0)
+		if first.Get("body").String() != "hello" {
+			return fmt.Errorf("first message body must be 'hello', was %s", first.Get("body"))
+		}
+		if first.Get("options").Get("contentType").String() != "json" {
+			return fmt.Errorf("first message content type must be json, was %s", first.Get("options").Get("contentType"))
+		}
+
+		second := batch.Index(1)
+		if second.Get("body").String() != "world" {
+			return fmt.Errorf("second message body must be 'world', was %s", second.Get("body"))
+		}
+		if second.Get("options").Get("contentType").String() != "text" {
+			return fmt.Errorf("second message content type must be text, was %s", second.Get("options").Get("contentType"))
+		}
+
+		return nil
+	}
+
+	var batch []*BatchMessage = []*BatchMessage{
+		NewBatchMessage("hello"),
+		NewBatchMessage("world", WithContentType(QueueContentTypeText)),
+	}
+
+	producer := validatingProducer(t, validation)
+	err := producer.SendBatch(batch)
+	if err != nil {
+		t.Fatalf("SendBatch failed: %v", err)
+	}
+}
+
+func TestSendBatch_Options(t *testing.T) {
+	validation := func(_ js.Value, options js.Value) error {
+		if options.Get("delaySeconds").Int() != 5 {
+			return fmt.Errorf("expected delay 5, got %d", options.Get("delaySeconds").Int())
+		}
+		return nil
+	}
+
+	var batch []*BatchMessage = []*BatchMessage{
+		NewBatchMessage("hello"),
+	}
+
+	producer := validatingProducer(t, validation)
+	err := producer.SendBatch(batch, WithBatchDelay(5*time.Second))
+	if err != nil {
+		t.Fatalf("SendBatch failed: %v", err)
+	}
+}
diff --git a/internal/jsutil/jsutil.go b/internal/jsutil/jsutil.go
index ececd04..5210d86 100644
--- a/internal/jsutil/jsutil.go
+++ b/internal/jsutil/jsutil.go
@@ -26,6 +26,10 @@ func NewObject() js.Value {
 	return ObjectClass.New()
 }
 
+func NewArray(size int) js.Value {
+	return ArrayClass.New(size)
+}
+
 func NewUint8Array(size int) js.Value {
 	return Uint8ArrayClass.New(size)
 }
@@ -89,7 +93,7 @@ func StrRecordToMap(v js.Value) map[string]string {
 	return result
 }
 
-// MaybeString returns string value of given JavaScript value or returns nil if the value is undefined.
+// MaybeString returns string value of given JavaScript value or returns "" if the value is undefined.
 func MaybeString(v js.Value) string {
 	if v.IsUndefined() {
 		return ""