diff --git a/plugin.go b/plugin.go
index 9f6431f..1afb133 100644
--- a/plugin.go
+++ b/plugin.go
@@ -126,35 +126,32 @@ type (
 
 	// Plugin values.
 	Plugin struct {
-		GitHub  GitHub
-		Repo    Repo
-		Build   Build
-		Source  Source
-		Config  Config
-		Payload Payload
-		Commit  Commit
+		GitHub     GitHub
+		Repo       Repo
+		Build      Build
+		Source     Source
+		Config     Config
+		Payload    Payload
+		Commit     Commit
+		httpClient *http.Client
 	}
 )
 
 func (c *Config) validate() error {
-	var missingFields []string
-
 	if c.webhookURL != "" {
-		_, err := url.Parse(c.webhookURL)
-		if err != nil {
+		if _, err := url.Parse(c.webhookURL); err != nil {
 			return fmt.Errorf("invalid webhook url: %w", err)
 		}
+		return nil
 	}
 
-	if c.webhookURL == "" {
-		if c.WebhookID == "" {
-			missingFields = append(missingFields, "WebhookID")
-		}
-		if c.WebhookToken == "" {
-			missingFields = append(missingFields, "WebhookToken")
-		}
+	var missingFields []string
+	if c.WebhookID == "" {
+		missingFields = append(missingFields, "WebhookID")
+	}
+	if c.WebhookToken == "" {
+		missingFields = append(missingFields, "WebhookToken")
 	}
-
 	if len(missingFields) > 0 {
 		return fmt.Errorf("missing discord config: %s", strings.Join(missingFields, ", "))
 	}
@@ -178,17 +175,12 @@ func templateMessage(t string, plugin Plugin) (string, error) {
 func fileUploadRequest(ctx context.Context, uri string, params map[string]string, paramName, path string) (*http.Request, error) {
 	// Clean and check path
 	path = filepath.Clean(path)
-	if _, err := os.Stat(path); err != nil {
+	file, err := os.Open(path)
+	if err != nil {
 		return nil, fmt.Errorf("file %s not accessible: %w", path, err)
 	}
+	defer file.Close()
 
-	// Read file content
-	content, err := os.ReadFile(path)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read file %s: %w", path, err)
-	}
-
-	// Create multipart form
 	body := &bytes.Buffer{}
 	writer := multipart.NewWriter(body)
 
@@ -197,7 +189,9 @@ func fileUploadRequest(ctx context.Context, uri string, params map[string]string
 	if err != nil {
 		return nil, fmt.Errorf("failed to create form file: %w", err)
 	}
-	if _, err = part.Write(content); err != nil {
+
+	// Stream file content
+	if _, err = io.Copy(part, file); err != nil {
 		return nil, fmt.Errorf("failed to write file content: %w", err)
 	}
 
@@ -224,65 +218,84 @@ func fileUploadRequest(ctx context.Context, uri string, params map[string]string
 
 // Exec executes the plugin.
 func (p *Plugin) Exec(ctx context.Context) error {
+	// init http client
+	p.httpClient = &http.Client{
+		Timeout: 15 * time.Second,
+	}
+
 	if err := p.Config.validate(); err != nil {
 		return fmt.Errorf("failed to validate config: %w", err)
 	}
 
-	// check if message is empty
-	messages := []string{}
+	if err := p.handleMessages(ctx); err != nil {
+		return err
+	}
+
+	if err := p.handleFiles(ctx); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// handleMessages sends all configured messages.
+func (p *Plugin) handleMessages(ctx context.Context) error {
+	// 1. Handle empty message (default template)
+	if len(p.Config.Message) == 0 {
+		object := p.Template()
+		p.Payload.Embeds = []EmbedObject{object}
+		if err := p.SendMessage(ctx); err != nil {
+			return fmt.Errorf("failed to send default message: %w", err)
+		}
+		return nil
+	}
+
+	// 2. Handle custom messages
 	for _, m := range p.Config.Message {
 		if m == "" {
 			continue
 		}
-		messages = append(messages, m)
-	}
 
-	if len(messages) == 0 {
-		object := p.Template()
-		p.Payload.Embeds = []EmbedObject{object}
-		err := p.SendMessage(ctx)
+		txt, err := templateMessage(m, *p)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to render template: %w", err)
+		}
+
+		// With color, messages are grouped as embeds
+		if p.Config.Color != "" {
+			object := p.DefaultTemplate(txt)
+			p.Payload.Embeds = append(p.Payload.Embeds, object)
+		} else {
+			// Without color, send as plain text immediately
+			p.Payload.Content = txt
+			if err := p.SendMessage(ctx); err != nil {
+				return fmt.Errorf("failed to send plain text message: %w", err)
+			}
+			// Reset for next message
+			p.Clear()
 		}
 	}
 
-	if len(messages) > 0 {
-		for _, m := range messages {
-			txt, err := templateMessage(m, *p)
-			if err != nil {
-				return err
-			}
-
-			if len(p.Config.Color) != 0 {
-				object := p.DefaultTemplate(txt)
-				p.Payload.Embeds = append(p.Payload.Embeds, object)
-			} else {
-				p.Payload.Content = txt
-				err = p.SendMessage(ctx)
-				if err != nil {
-					return err
-				}
-			}
-		}
-
-		if len(p.Payload.Embeds) > 0 {
-			err := p.SendMessage(ctx)
-			if err != nil {
-				return err
-			}
+	// 3. Send grouped embeds if any
+	if len(p.Payload.Embeds) > 0 {
+		if err := p.SendMessage(ctx); err != nil {
+			return fmt.Errorf("failed to send embed messages: %w", err)
 		}
 	}
 
+	return nil
+}
+
+// handleFiles sends all configured files.
+func (p *Plugin) handleFiles(ctx context.Context) error {
 	for _, f := range p.Config.File {
 		if f == "" {
 			continue
 		}
-		err := p.SendFile(ctx, f)
-		if err != nil {
-			return err
+		if err := p.SendFile(ctx, f); err != nil {
+			return fmt.Errorf("failed to send file %s: %w", f, err)
 		}
 	}
-
 	return nil
 }
 
@@ -311,12 +324,25 @@ func (p *Plugin) SendFile(ctx context.Context, file string) error {
 		file,
 	)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to create file upload request: %w", err)
 	}
-	client := &http.Client{}
-	_, err = client.Do(request)
+
+	resp, err := p.httpClient.Do(request)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to send file: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= http.StatusBadRequest {
+		bodyBytes, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return fmt.Errorf("failed to read response body: %w", err)
+		}
+		var jsonResponse map[string]interface{}
+		if err := json.Unmarshal(bodyBytes, &jsonResponse); err != nil {
+			return fmt.Errorf("failed to send file, status code: %d, body: %s", resp.StatusCode, string(bodyBytes))
+		}
+		return fmt.Errorf("failed to send file, status code: %d, error: %s, code: %v", resp.StatusCode, jsonResponse["message"], jsonResponse["code"])
 	}
 
 	return nil
@@ -327,25 +353,23 @@ func (p *Plugin) SendMessage(ctx context.Context) error {
 	webhookURL := p.Config.GetWebhookURL()
 	b := new(bytes.Buffer)
 	if err := json.NewEncoder(b).Encode(p.Payload); err != nil {
-		return err
+		return fmt.Errorf("failed to encode payload: %w", err)
 	}
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, b)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to create request: %w", err)
 	}
 	req.Header.Set("Content-Type", "application/json; charset=utf-8")
 
-	client := &http.Client{
-		Timeout: 10 * time.Second,
-	}
-	resp, err := client.Do(req)
+	resp, err := p.httpClient.Do(req)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to send message: %w", err)
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode != http.StatusNoContent {
+	// 200 and 204 are both valid status codes for webhooks.
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
 		bodyBytes, err := io.ReadAll(resp.Body)
 		if err != nil {
 			return fmt.Errorf("failed to read response body: %w", err)
diff --git a/plugin_test.go b/plugin_test.go
index 127afbd..22c992d 100644
--- a/plugin_test.go
+++ b/plugin_test.go
@@ -10,14 +10,48 @@ import (
 )
 
 func TestMissingConfig(t *testing.T) {
-	var plugin Plugin
+	plugin := Plugin{}
 
 	err := plugin.Exec(context.Background())
 
-	assert.NotNil(t, err)
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "missing discord config")
 }
 
-func TestTemplate(t *testing.T) {
+func TestSendPlainTextMessage(t *testing.T) {
+	plugin := Plugin{
+		Config: Config{
+			WebhookID:    os.Getenv("WEBHOOK_ID"),
+			WebhookToken: os.Getenv("WEBHOOK_TOKEN"),
+			Message:      []string{"Hello, world!", "This is a test."},
+		},
+		Payload: Payload{
+			Username: "test-bot",
+		},
+	}
+
+	err := plugin.Exec(context.Background())
+	assert.NoError(t, err)
+}
+
+func TestSendEmbedMessage(t *testing.T) {
+	plugin := Plugin{
+		Config: Config{
+			WebhookID:    os.Getenv("WEBHOOK_ID"),
+			WebhookToken: os.Getenv("WEBHOOK_TOKEN"),
+			Message:      []string{"This is an embed message."},
+			Color:        "#48f442",
+		},
+		Payload: Payload{
+			Username: "embed-bot",
+		},
+	}
+
+	err := plugin.Exec(context.Background())
+	assert.NoError(t, err)
+}
+
+func TestSendDefaultMessage(t *testing.T) {
 	plugin := Plugin{
 		Repo: Repo{
 			Name:      "go-hello",
@@ -26,99 +60,120 @@ func TestTemplate(t *testing.T) {
 		Commit: Commit{
 			Author:  "appleboy",
 			Branch:  "master",
-			Message: "update by drone discord plugin. \r\n update by drone discord plugin.",
+			Message: "feat: new feature",
 			Avatar:  "https://avatars0.githubusercontent.com/u/21979?v=3&s=100",
 		},
 		Build: Build{
 			Number: 101,
 			Status: "success",
 			Link:   "https://github.com/appleboy/go-hello",
-			Event:  "tag",
+			Event:  "push",
 		},
-		Source: Source{
-			Branch: "feature/awesome-feature",
-		},
-
 		Config: Config{
 			WebhookID:    os.Getenv("WEBHOOK_ID"),
 			WebhookToken: os.Getenv("WEBHOOK_TOKEN"),
-			Message:      []string{"test one message from drone testing", "test two message from drone testing"},
-			File:         []string{"./images/discord-logo.png"},
 			Drone:        true,
 		},
-
 		Payload: Payload{
-			Username: "drone",
-			TTS:      false,
-			Wait:     false,
+			Username: "default-bot",
 		},
 	}
 
 	err := plugin.Exec(context.Background())
-	assert.Nil(t, err)
-
-	plugin.Clear()
-	plugin.Config.Message = []string{"I am appleboy"}
-	plugin.Payload.TTS = true
-	plugin.Payload.Wait = true
-	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
-
-	// send success embed message
-	plugin.Config.Message = []string{}
-	plugin.Payload.TTS = false
-	plugin.Payload.Wait = false
-	plugin.Clear()
-	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
-
-	// send success embed message
-	plugin.Build.Status = "failure"
-	plugin.Commit.Message = "send failure embed message"
-	plugin.Clear()
-	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
-	time.Sleep(1 * time.Second)
-
-	// send default embed message
-	plugin.Build.Status = "test"
-	plugin.Commit.Message = "send default embed message"
-	plugin.Clear()
-	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
-
-	// change color for embed message
-	plugin.Config.Color = "#4842f4"
-	plugin.Commit.Message = "Change embed color to #4842f4"
-	plugin.Clear()
-	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
+	assert.NoError(t, err)
 }
 
-func TestDefaultTemplate(t *testing.T) {
+func TestSendFile(t *testing.T) {
+	// Create a dummy file for testing
+	dummyFile, err := os.Create("test_file.txt")
+	assert.NoError(t, err)
+	_, err = dummyFile.WriteString("This is a test file.")
+	assert.NoError(t, err)
+	dummyFile.Close()
+	defer os.Remove("test_file.txt")
+
 	plugin := Plugin{
 		Config: Config{
 			WebhookID:    os.Getenv("WEBHOOK_ID"),
 			WebhookToken: os.Getenv("WEBHOOK_TOKEN"),
-			Message:      []string{"default message 1", "default message 2"},
-			Color:        "#48f442",
+			File:         []string{"test_file.txt"},
 		},
-
 		Payload: Payload{
-			Username: "drone-ci",
-			TTS:      false,
-			Wait:     false,
+			Username: "file-bot",
 		},
 	}
 
-	time.Sleep(1 * time.Second)
-	plugin.Clear()
-	err := plugin.Exec(context.Background())
-	assert.Nil(t, err)
-
-	plugin.Config.Color = "#f4be41"
-	time.Sleep(1 * time.Second)
-	plugin.Clear()
 	err = plugin.Exec(context.Background())
-	assert.Nil(t, err)
+	assert.NoError(t, err)
+}
+
+func TestColorConversion(t *testing.T) {
+	tests := []struct {
+		name         string
+		colorHex     string
+		expectedInt  int
+		buildStatus  string
+		expectedFall int
+	}{
+		{"valid hex", "#ffaa00", 16755200, "success", 1752220},
+		{"invalid hex", "not-a-hex", 0, "failure", 16724530},
+		{"status success", "", 0, "success", 1752220},
+		{"status failure", "", 0, "failure", 16724530},
+		{"status killed", "", 0, "killed", 16724530},
+		{"status default", "", 0, "running", 16767280},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := Plugin{
+				Config: Config{Color: tt.colorHex},
+				Build:  Build{Status: tt.buildStatus},
+			}
+			if tt.colorHex != "" {
+				assert.Equal(t, tt.expectedInt, p.Color())
+			} else {
+				assert.Equal(t, tt.expectedFall, p.Color())
+			}
+		})
+	}
+}
+
+func TestExecWithAllFeatures(t *testing.T) {
+	time.Sleep(1 * time.Second)
+	// Create a dummy file for testing
+	dummyFile, err := os.Create("test_all.txt")
+	assert.NoError(t, err)
+	_, err = dummyFile.WriteString("This is a test file for a combined test.")
+	assert.NoError(t, err)
+	dummyFile.Close()
+	defer os.Remove("test_all.txt")
+
+	plugin := Plugin{
+		Repo: Repo{
+			Name:      "go-hello",
+			Namespace: "appleboy",
+		},
+		Commit: Commit{
+			Author:  "appleboy",
+			Message: "Combined test with multiple features",
+		},
+		Build: Build{
+			Status: "success",
+			Link:   "http://example.com",
+		},
+		Config: Config{
+			WebhookID:    os.Getenv("WEBHOOK_ID"),
+			WebhookToken: os.Getenv("WEBHOOK_TOKEN"),
+			Message:      []string{"First line of embed.", "Second line."},
+			File:         []string{"test_all.txt"},
+			Color:        "#32a852",
+			Drone:        true,
+		},
+		Payload: Payload{
+			Username: "super-bot",
+		},
+	}
+
+	err = plugin.Exec(context.Background())
+	assert.NoError(t, err)
 }