diff --git a/.claude/settings.local.json b/.claude/settings.local.json
index 94124bb..a1fc14f 100644
--- a/.claude/settings.local.json
+++ b/.claude/settings.local.json
@@ -8,7 +8,8 @@
       "Bash(git commit *)",
       "Bash(go vet *)",
       "Bash(/Users/ryan/.claude/plugins/cache/superpowers-marketplace/superpowers/6.0.3/skills/subagent-driven-development/scripts/task-brief *)",
-      "Bash(go get *)"
+      "Bash(go get *)",
+      "Bash(go test *)"
     ]
   }
 }
diff --git a/internal/adapter/adapter.go b/internal/adapter/adapter.go
new file mode 100644
index 0000000..a6cf66a
--- /dev/null
+++ b/internal/adapter/adapter.go
@@ -0,0 +1,29 @@
+package adapter
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"aiaa-notification-service/internal/config"
+)
+
+// ChannelSender sends a rendered message to a specific channel.
+type ChannelSender interface {
+	Type() string
+	Send(title, content string, config json.RawMessage) error
+}
+
+func NewSender(channelType string, smtpCfg *config.SMTPConfig) (ChannelSender, error) {
+	switch channelType {
+	case "dingtalk":
+		return &DingTalkSender{}, nil
+	case "wecom":
+		return &WeComSender{}, nil
+	case "bark":
+		return &BarkSender{}, nil
+	case "email":
+		return nil, fmt.Errorf("email sender not yet implemented (see Task 10)")
+	default:
+		return nil, fmt.Errorf("unknown channel type: %s", channelType)
+	}
+}
diff --git a/internal/adapter/bark.go b/internal/adapter/bark.go
new file mode 100644
index 0000000..5c62ddf
--- /dev/null
+++ b/internal/adapter/bark.go
@@ -0,0 +1,41 @@
+package adapter
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+type barkConfig struct {
+	URL string `json:"url"`
+}
+
+type barkPayload struct {
+	Title string `json:"title"`
+	Body  string `json:"body"`
+}
+
+type BarkSender struct{}
+
+func (s *BarkSender) Type() string { return "bark" }
+
+func (s *BarkSender) Send(title, content string, config json.RawMessage) error {
+	var cfg barkConfig
+	if err := json.Unmarshal(config, &cfg); err != nil {
+		return fmt.Errorf("parse bark config: %w", err)
+	}
+
+	payload := barkPayload{Title: title, Body: content}
+	body, _ := json.Marshal(payload)
+	resp, err := http.Post(cfg.URL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		return fmt.Errorf("bark send: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		return fmt.Errorf("bark returned status %d", resp.StatusCode)
+	}
+	return nil
+}
diff --git a/internal/adapter/dingtalk.go b/internal/adapter/dingtalk.go
new file mode 100644
index 0000000..dd94c38
--- /dev/null
+++ b/internal/adapter/dingtalk.go
@@ -0,0 +1,73 @@
+package adapter
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+type dingtalkConfig struct {
+	WebhookURL string `json:"webhook_url"`
+	Secret     string `json:"secret,omitempty"`
+}
+
+type dingtalkMessage struct {
+	MsgType  string      `json:"msgtype"`
+	Markdown *dingtalkMD `json:"markdown"`
+}
+
+type dingtalkMD struct {
+	Title string `json:"title"`
+	Text  string `json:"text"`
+}
+
+type DingTalkSender struct{}
+
+func (s *DingTalkSender) Type() string { return "dingtalk" }
+
+func (s *DingTalkSender) Send(title, content string, config json.RawMessage) error {
+	var cfg dingtalkConfig
+	if err := json.Unmarshal(config, &cfg); err != nil {
+		return fmt.Errorf("parse dingtalk config: %w", err)
+	}
+
+	reqURL := cfg.WebhookURL
+	if cfg.Secret != "" {
+		timestamp := time.Now().UnixMilli()
+		sign := dingtalkSign(timestamp, cfg.Secret)
+		reqURL = fmt.Sprintf("%s&timestamp=%d&sign=%s", cfg.WebhookURL, timestamp, sign)
+	}
+
+	msg := dingtalkMessage{
+		MsgType: "markdown",
+		Markdown: &dingtalkMD{
+			Title: title,
+			Text:  content,
+		},
+	}
+
+	body, _ := json.Marshal(msg)
+	resp, err := http.Post(reqURL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		return fmt.Errorf("dingtalk send: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		return fmt.Errorf("dingtalk returned status %d", resp.StatusCode)
+	}
+	return nil
+}
+
+func dingtalkSign(timestamp int64, secret string) string {
+	mac := hmac.New(sha256.New, []byte(secret))
+	fmt.Fprintf(mac, "%d\n%s", timestamp, secret)
+	signData := mac.Sum(nil)
+	return url.QueryEscape(base64.StdEncoding.EncodeToString(signData))
+}
diff --git a/internal/adapter/wecom.go b/internal/adapter/wecom.go
new file mode 100644
index 0000000..130e73e
--- /dev/null
+++ b/internal/adapter/wecom.go
@@ -0,0 +1,51 @@
+package adapter
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+type wecomConfig struct {
+	WebhookURL string `json:"webhook_url"`
+}
+
+type wecomMessage struct {
+	MsgType  string   `json:"msgtype"`
+	Markdown *wecomMD `json:"markdown"`
+}
+
+type wecomMD struct {
+	Content string `json:"content"`
+}
+
+type WeComSender struct{}
+
+func (s *WeComSender) Type() string { return "wecom" }
+
+func (s *WeComSender) Send(title, content string, config json.RawMessage) error {
+	var cfg wecomConfig
+	if err := json.Unmarshal(config, &cfg); err != nil {
+		return fmt.Errorf("parse wecom config: %w", err)
+	}
+
+	msg := wecomMessage{
+		MsgType: "markdown",
+		Markdown: &wecomMD{
+			Content: fmt.Sprintf("## %s\n%s", title, content),
+		},
+	}
+
+	body, _ := json.Marshal(msg)
+	resp, err := http.Post(cfg.WebhookURL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		return fmt.Errorf("wecom send: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		return fmt.Errorf("wecom returned status %d", resp.StatusCode)
+	}
+	return nil
+}