diff --git a/examples/81-fake-callback-client/main.go b/examples/81-fake-callback-client/main.go
new file mode 100644
index 0000000..8a55fe8
--- /dev/null
+++ b/examples/81-fake-callback-client/main.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/go-deepseek/deepseek"
+	"github.com/go-deepseek/deepseek/request"
+)
+
+/*
+Example Details:
+
+Example shows how to use FakeCallbackClient to test user feature which is using go-deepseek client.
+
+Here, Greeter() is user feature when invoke from main() needs deepseek client with DEEPSEEK_API_KEY
+
+Check TestGreeter() in main_test.go file.  It is testing user feature Greeter() using FakeCallbackClient.  This does not need deepseek with DEEPSEEK_API_KEY.
+
+Using FakeCallbackClient, you will be able to develop your feature and test your feature even though deepseek API is down.
+*/
+
+func main() {
+	client, err := deepseek.NewClient(os.Getenv("DEEPSEEK_API_KEY"))
+	if err != nil {
+		panic(err)
+	}
+	reply := Greeter(client, "Hello")
+	fmt.Println(reply)
+}
+
+func Greeter(client deepseek.Client, message string) string {
+	chatReq := &request.ChatCompletionsRequest{
+		Model: deepseek.DEEPSEEK_CHAT_MODEL,
+		Messages: []*request.Message{
+			{
+				Role:    "user",
+				Content: message,
+			},
+		},
+		Stream: false,
+	}
+
+	resp, err := client.CallChatCompletionsChat(context.Background(), chatReq)
+	if err != nil {
+		panic(err)
+	}
+
+	reply := resp.Choices[0].Message.Content
+	return reply
+}
diff --git a/examples/81-fake-callback-client/main_test.go b/examples/81-fake-callback-client/main_test.go
new file mode 100644
index 0000000..dffb0c3
--- /dev/null
+++ b/examples/81-fake-callback-client/main_test.go
@@ -0,0 +1,56 @@
+package main
+
+import (
+	"context"
+	"testing"
+
+	"github.com/go-deepseek/deepseek/fake"
+	"github.com/go-deepseek/deepseek/request"
+	"github.com/go-deepseek/deepseek/response"
+)
+
+func TestGreeter(t *testing.T) {
+	callbacks := fake.Callbacks{}
+
+	callbacks.CallChatCompletionsChatCallback = func(ctx context.Context, chatReq *request.ChatCompletionsRequest) (*response.ChatCompletionsResponse, error) {
+		if chatReq.Messages[0].Content == "Hello" {
+			chatResp := &response.ChatCompletionsResponse{
+				Choices: []*response.Choice{
+					{
+						Message: &response.Message{
+							Content: "How are you?",
+						},
+					},
+				},
+			}
+			return chatResp, nil
+		}
+
+		if chatReq.Messages[0].Content == "Bye" {
+			chatResp := &response.ChatCompletionsResponse{
+				Choices: []*response.Choice{
+					{
+						Message: &response.Message{
+							Content: "Good Day!",
+						},
+					},
+				},
+			}
+			return chatResp, nil
+		}
+
+		return nil, nil
+	}
+
+	client := fake.NewFakeCallbackClient(callbacks)
+
+	reply := Greeter(client, "Hello")
+	if reply != "How are you?" {
+		t.Fail()
+	}
+
+	reply = Greeter(client, "Bye")
+	if reply != "Good Day!" {
+		t.Fail()
+	}
+}
diff --git a/fake/callback_client.go b/fake/callback_client.go
new file mode 100644
index 0000000..54d5c8f
--- /dev/null
+++ b/fake/callback_client.go
@@ -0,0 +1,64 @@
+package fake
+
+import (
+	"context"
+
+	"github.com/go-deepseek/deepseek/request"
+	"github.com/go-deepseek/deepseek/response"
+)
+
+type Callbacks struct {
+	CallChatCompletionsChatCallback     func(ctx context.Context, chatReq *request.ChatCompletionsRequest) (*response.ChatCompletionsResponse, error)
+	CallChatCompletionsReasonerCallback func(ctx context.Context, chatReq *request.ChatCompletionsRequest) (*response.ChatCompletionsResponse, error)
+
+	StreamChatCompletionsChatCallback     func(ctx context.Context, chatReq *request.ChatCompletionsRequest) (response.StreamReader, error)
+	StreamChatCompletionsReasonerCallback func(ctx context.Context, chatReq *request.ChatCompletionsRequest) (response.StreamReader, error)
+
+	PingChatCompletionsCallback func(ctx context.Context, inputMessage string) (outputMessge string, err error)
+}
+
+type FakeCallbackClient struct {
+	callbacks Callbacks
+}
+
+func NewFakeCallbackClient(callbacks Callbacks) *FakeCallbackClient {
+	fc := &FakeCallbackClient{
+		callbacks: callbacks,
+	}
+	return fc
+}
+
+func (c *FakeCallbackClient) CallChatCompletionsChat(ctx context.Context, chatReq *request.ChatCompletionsRequest) (*response.ChatCompletionsResponse, error) {
+	if c.callbacks.CallChatCompletionsChatCallback == nil {
+		panic("err: CallChatCompletionsChatCallback is nil")
+	}
+	return c.callbacks.CallChatCompletionsChatCallback(ctx, chatReq)
+}
+
+func (c *FakeCallbackClient) CallChatCompletionsReasoner(ctx context.Context, chatReq *request.ChatCompletionsRequest) (*response.ChatCompletionsResponse, error) {
+	if c.callbacks.CallChatCompletionsReasonerCallback == nil {
+		panic("err: CallChatCompletionsReasonerCallback is nil")
+	}
+	return c.callbacks.CallChatCompletionsReasonerCallback(ctx, chatReq)
+}
+
+func (c *FakeCallbackClient) StreamChatCompletionsChat(ctx context.Context, chatReq *request.ChatCompletionsRequest) (response.StreamReader, error) {
+	if c.callbacks.StreamChatCompletionsChatCallback == nil {
+		panic("err: StreamChatCompletionsChatCallback is nil")
+	}
+	return c.callbacks.StreamChatCompletionsChatCallback(ctx, chatReq)
+}
+
+func (c *FakeCallbackClient) StreamChatCompletionsReasoner(ctx context.Context, chatReq *request.ChatCompletionsRequest) (response.StreamReader, error) {
+	if c.callbacks.StreamChatCompletionsReasonerCallback == nil {
+		panic("err: StreamChatCompletionsReasonerCallback is nil")
+	}
+	return c.callbacks.StreamChatCompletionsReasonerCallback(ctx, chatReq)
+}
+
+func (c *FakeCallbackClient) PingChatCompletions(ctx context.Context, inputMessage string) (outputMessge string, err error) {
+	if c.callbacks.PingChatCompletionsCallback == nil {
+		panic("err: PingChatCompletionsCallback is nil")
+	}
+	return c.callbacks.PingChatCompletionsCallback(ctx, inputMessage)
+}