diff --git a/go.mod b/go.mod
index 7e788c96ba..d399ffe451 100644
--- a/go.mod
+++ b/go.mod
@@ -42,6 +42,7 @@ require (
 	github.com/nats-io/nats-server/v2 v2.14.3
 	github.com/nats-io/nats.go v1.52.0
 	github.com/nikolalohinski/gonja v1.5.3
+	github.com/open-dingtalk/dingtalk-stream-sdk-go v0.0.5
 	github.com/peterh/liner v1.2.2
 	github.com/pkoukk/tiktoken-go v0.1.8
 	github.com/redis/go-redis/v9 v9.18.0
diff --git a/go.sum b/go.sum
index 69b65466dc..e82da0b254 100644
--- a/go.sum
+++ b/go.sum
@@ -394,6 +394,8 @@ github.com/oapi-codegen/runtime v1.4.0/go.mod h1:5sw5fxCDmnOzKNYmkVNF8d34kyUeejJ
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.8.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.5.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/open-dingtalk/dingtalk-stream-sdk-go v0.0.5 h1:CUAhJXmX6soVTbC6hEjR8J9BqfItW/osZpQ7LAdKtCs=
+github.com/open-dingtalk/dingtalk-stream-sdk-go v0.0.5/go.mod h1:ln3IqPYYocZbYvl9TAOrG/cxGR9xcn4pnZRLdCTEGEU=
 github.com/pelletier/go-toml/v2 v2.3.1 h1:MYEvvGnQjeNkRF1qUuGolNtNExTDwct51yp7olPtrEc=
 github.com/pelletier/go-toml/v2 v2.3.1/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 github.com/peterh/liner v1.2.2 h1:aJ4AOodmL+JxOZZEL2u9iJf8omNRpqHc/EbrK+3mAXw=
diff --git a/internal/channels/bootstrap.go b/internal/channels/bootstrap.go
index 3da5899bd7..44431a6c54 100644
--- a/internal/channels/bootstrap.go
+++ b/internal/channels/bootstrap.go
@@ -279,6 +279,8 @@ func buildChannel(accountID string, wanted desiredChannel) (core.Channel, error)
 	switch wanted.channel {
 	case "whatsapp":
 		return newWhatsAppChannelFromConfig(accountID, wanted.credential)
+	case "dingtalk":
+		return newDingTalkChannelFromConfig(accountID, wanted.credential)
 	default:
 		return nil, fmt.Errorf("unknown channel: %s", wanted.channel)
 	}
diff --git a/internal/channels/dingtalk.go b/internal/channels/dingtalk.go
index a4ce67278c..a49e89078d 100644
--- a/internal/channels/dingtalk.go
+++ b/internal/channels/dingtalk.go
@@ -15,3 +15,542 @@
 //
 
 package channels
+
+import (
+	"bytes"
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/open-dingtalk/dingtalk-stream-sdk-go/chatbot"
+	"github.com/open-dingtalk/dingtalk-stream-sdk-go/clientV2"
+	"github.com/open-dingtalk/dingtalk-stream-sdk-go/payload"
+
+	"ragflow/internal/channels/core"
+)
+
+const (
+	defaultDingTalkAPIBaseURL = "https://api.dingtalk.com"
+	defaultDingTalkTimeout    = 30 * time.Second
+	dingTalkMessageTTL        = time.Hour
+	dingTalkQueueSize         = 64
+	dingTalkWorkerIdle        = 5 * time.Minute
+)
+
+type dingTalkAccount struct {
+	AccountID    string
+	ClientID     string
+	ClientSecret string
+	APIBaseURL   string
+	Timeout      time.Duration
+}
+
+type dingTalkChannel struct {
+	account dingTalkAccount
+
+	mu              sync.Mutex
+	ctx             context.Context
+	cancel          context.CancelFunc
+	handler         core.MessageHandler
+	client          *http.Client
+	stream          clientV2.OpenDingTalkClient
+	sessionWebhooks map[string]string
+	processed       map[string]time.Time
+	inflight        map[string]time.Time
+	workers         map[string]*dingTalkWorker
+}
+
+type dingTalkWorker struct {
+	queue chan dingTalkQueuedMessage
+}
+
+type dingTalkQueuedMessage struct {
+	incoming core.IncomingMessage
+	dedupKey string
+}
+
+// newDingTalkChannel creates a DingTalk stream channel backed by the official SDK.
+func newDingTalkChannel(account dingTalkAccount) *dingTalkChannel {
+	if account.APIBaseURL == "" {
+		account.APIBaseURL = defaultDingTalkAPIBaseURL
+	}
+	if account.Timeout <= 0 {
+		account.Timeout = defaultDingTalkTimeout
+	}
+	ch := &dingTalkChannel{
+		account:         account,
+		client:          &http.Client{Timeout: account.Timeout},
+		sessionWebhooks: map[string]string{},
+		processed:       map[string]time.Time{},
+		inflight:        map[string]time.Time{},
+		workers:         map[string]*dingTalkWorker{},
+	}
+	ch.stream = clientV2.NewBuilder().
+		Credential(&clientV2.AuthClientCredential{ClientId: account.ClientID, ClientSecret: account.ClientSecret}).
+		RegisterCallbackHandler(payload.BotMessageCallbackTopic, ch.handleBotCallback).
+		Build()
+	return ch
+}
+
+// newDingTalkChannelFromConfig builds a DingTalk channel from chat_channel.config.credential.
+func newDingTalkChannelFromConfig(accountID string, cfg map[string]any) (*dingTalkChannel, error) {
+	clientID := firstString(cfg, "client_id", "clientId")
+	clientSecret := firstString(cfg, "client_secret", "clientSecret")
+	if clientID == "" || clientSecret == "" {
+		return nil, fmt.Errorf("dingtalk account %q is missing client_id or client_secret", accountID)
+	}
+
+	timeout := defaultDingTalkTimeout
+	if raw, ok := cfg["timeout_secs"]; ok {
+		if parsed := dingTalkDurationSeconds(raw); parsed > 0 {
+			timeout = parsed
+		}
+	}
+
+	return newDingTalkChannel(dingTalkAccount{
+		AccountID:    accountID,
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		APIBaseURL:   firstString(cfg, "api_base_url", "api_url"),
+		Timeout:      timeout,
+	}), nil
+}
+
+// ChannelID returns the platform identifier used by the chat-channel runtime.
+func (c *dingTalkChannel) ChannelID() string {
+	return "dingtalk"
+}
+
+// AccountID returns the chat_channel.id bound to this DingTalk runtime instance.
+func (c *dingTalkChannel) AccountID() string {
+	return c.account.AccountID
+}
+
+// SetMessageHandler installs the RAGFlow bridge invoked for inbound DingTalk messages.
+func (c *dingTalkChannel) SetMessageHandler(handler core.MessageHandler) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.handler = handler
+}
+
+// Start begins the DingTalk official stream client.
+func (c *dingTalkChannel) Start(ctx context.Context) error {
+	c.mu.Lock()
+	if c.cancel != nil {
+		c.mu.Unlock()
+		return nil
+	}
+	runCtx, cancel := context.WithCancel(ctx)
+	c.ctx = runCtx
+	c.cancel = cancel
+	c.mu.Unlock()
+
+	go c.run(runCtx)
+	return nil
+}
+
+// Stop cancels the DingTalk stream client and clears transient runtime state.
+func (c *dingTalkChannel) Stop(ctx context.Context) error {
+	c.mu.Lock()
+	cancel := c.cancel
+	c.cancel = nil
+	c.ctx = nil
+	c.sessionWebhooks = map[string]string{}
+	c.processed = map[string]time.Time{}
+	c.inflight = map[string]time.Time{}
+	c.workers = map[string]*dingTalkWorker{}
+	c.mu.Unlock()
+
+	if cancel != nil {
+		cancel()
+	}
+	return nil
+}
+
+// Send posts an outgoing RAGFlow answer to DingTalk through the cached sessionWebhook.
+func (c *dingTalkChannel) Send(ctx context.Context, msg core.OutgoingMessage) error {
+	if strings.TrimSpace(msg.ChatID) == "" {
+		return errors.New("chat_id is required")
+	}
+	if strings.TrimSpace(msg.Text) == "" {
+		return nil
+	}
+
+	c.mu.Lock()
+	sessionWebhook := c.sessionWebhooks[msg.ChatID]
+	c.mu.Unlock()
+	if strings.TrimSpace(sessionWebhook) == "" {
+		log.Printf("[dingtalk:%s] no sessionWebhook cached for chat_id=%s; dropping reply", c.account.AccountID, msg.ChatID)
+		return nil
+	}
+
+	p := map[string]any{
+		"msgtype": "markdown",
+		"markdown": map[string]string{
+			"title": "RAGFlow",
+			"text":  msg.Text,
+		},
+	}
+	return c.postWebhook(ctx, sessionWebhook, p)
+}
+
+// run keeps the DingTalk SDK stream client active until the channel stops.
+func (c *dingTalkChannel) run(ctx context.Context) {
+	defer func() {
+		var runCancel context.CancelFunc
+		c.mu.Lock()
+		if c.ctx == ctx {
+			runCancel = c.cancel
+		}
+		c.mu.Unlock()
+		if runCancel != nil {
+			runCancel()
+		}
+
+		c.mu.Lock()
+		if c.ctx == ctx {
+			c.cancel = nil
+			c.ctx = nil
+		}
+		c.mu.Unlock()
+	}()
+	if c.stream == nil {
+		log.Printf("[dingtalk:%s] stream client is not initialized", c.account.AccountID)
+		return
+	}
+	if err := c.stream.Start(ctx); err != nil && ctx.Err() == nil {
+		log.Printf("[dingtalk:%s] stream client exited: %v", c.account.AccountID, err)
+	}
+}
+
+// handleBotCallback receives DingTalk bot messages from the official stream SDK.
+func (c *dingTalkChannel) handleBotCallback(data *chatbot.BotCallbackDataModel) (*chatbot.BotCallbackRespModel, error) {
+	c.mu.Lock()
+	ctx := c.ctx
+	c.mu.Unlock()
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	incoming, dedupKey, ok := c.normalizeBotMessage(data)
+	if !ok {
+		return &chatbot.BotCallbackRespModel{}, nil
+	}
+	if dedupKey != "" && !c.beginMessage(dedupKey) {
+		log.Printf("[dingtalk:%s] skipping duplicate message=%s", c.account.AccountID, dedupKey)
+		return &chatbot.BotCallbackRespModel{}, nil
+	}
+	if !c.enqueueIncoming(ctx, dingTalkQueuedMessage{incoming: incoming, dedupKey: dedupKey}) && dedupKey != "" {
+		c.cancelInflight(dedupKey)
+	}
+	return &chatbot.BotCallbackRespModel{}, nil
+}
+
+// normalizeBotMessage converts DingTalk SDK bot callback data to the chat-channel message model.
+func (c *dingTalkChannel) normalizeBotMessage(data *chatbot.BotCallbackDataModel) (core.IncomingMessage, string, bool) {
+	if data == nil {
+		return core.IncomingMessage{}, "", false
+	}
+	chatID := dingTalkFirstNonEmpty(data.ConversationId)
+	senderID := dingTalkFirstNonEmpty(data.SenderId, data.SenderStaffId)
+	text := strings.TrimSpace(data.Text.Content)
+	if text == "" {
+		text = dingTalkExtractText(data.Content)
+	}
+	if data.SessionWebhook != "" && chatID != "" {
+		c.saveSessionWebhook(chatID, data.SessionWebhook)
+	}
+	if text == "" || chatID == "" || senderID == "" {
+		return core.IncomingMessage{}, "", false
+	}
+
+	raw := map[string]any{}
+	if encoded, err := json.Marshal(data); err == nil {
+		_ = json.Unmarshal(encoded, &raw)
+	}
+	dedupKey := dingTalkBotDedupKey(data, text)
+	return core.IncomingMessage{
+		Channel:   c.ChannelID(),
+		AccountID: c.account.AccountID,
+		ChatID:    chatID,
+		ChatType:  data.ConversationType,
+		MessageID: dingTalkFirstNonEmpty(data.MsgId, dedupKey),
+		SenderID:  senderID,
+		Text:      text,
+		Raw:       raw,
+	}, dedupKey, true
+}
+
+// enqueueIncoming schedules DingTalk message handling and marks duplicates as processed after handling.
+func (c *dingTalkChannel) enqueueIncoming(ctx context.Context, item dingTalkQueuedMessage) bool {
+	if ctx.Err() != nil {
+		return false
+	}
+
+	var worker *dingTalkWorker
+	startWorker := false
+	queueFull := false
+
+	c.mu.Lock()
+	if c.workers == nil {
+		c.workers = map[string]*dingTalkWorker{}
+	}
+	worker = c.workers[item.incoming.ChatID]
+	if worker == nil {
+		worker = &dingTalkWorker{queue: make(chan dingTalkQueuedMessage, dingTalkQueueSize)}
+		c.workers[item.incoming.ChatID] = worker
+		startWorker = true
+	}
+	select {
+	case worker.queue <- item:
+		c.mu.Unlock()
+		if startWorker {
+			go c.runWorker(ctx, item.incoming.ChatID, worker)
+		}
+		return true
+	case <-ctx.Done():
+		c.mu.Unlock()
+	default:
+		queueFull = true
+		c.mu.Unlock()
+	}
+	if startWorker {
+		go c.runWorker(ctx, item.incoming.ChatID, worker)
+	}
+	if queueFull {
+		log.Printf("[dingtalk:%s] dropping message %s for chat %s: queue is full", c.account.AccountID, item.incoming.MessageID, item.incoming.ChatID)
+	}
+	return false
+}
+
+// runWorker processes one DingTalk chat's inbound messages sequentially.
+func (c *dingTalkChannel) runWorker(ctx context.Context, chatID string, worker *dingTalkWorker) {
+	idle := time.NewTimer(dingTalkWorkerIdle)
+	defer idle.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case item := <-worker.queue:
+			if ctx.Err() != nil {
+				return
+			}
+			c.handleIncoming(ctx, item.incoming)
+			if item.dedupKey != "" {
+				c.finishMessage(item.dedupKey)
+			}
+			resetTimer(idle, dingTalkWorkerIdle)
+		case <-idle.C:
+			if c.retireWorker(chatID, worker) {
+				return
+			}
+			resetTimer(idle, dingTalkWorkerIdle)
+		}
+	}
+}
+
+// retireWorker removes an idle DingTalk chat worker only while it is current and empty.
+func (c *dingTalkChannel) retireWorker(chatID string, worker *dingTalkWorker) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	current := c.workers[chatID]
+	if current != worker {
+		return true
+	}
+	if len(worker.queue) > 0 {
+		return false
+	}
+	delete(c.workers, chatID)
+	return true
+}
+
+// handleIncoming invokes the installed RAGFlow bridge for one queued DingTalk message.
+func (c *dingTalkChannel) handleIncoming(ctx context.Context, incoming core.IncomingMessage) {
+	c.mu.Lock()
+	handler := c.handler
+	c.mu.Unlock()
+	if handler == nil {
+		return
+	}
+	if err := handler(ctx, incoming); err != nil {
+		log.Printf("[dingtalk:%s] message handler error: %v", c.account.AccountID, err)
+	}
+}
+
+// beginMessage marks a DingTalk message as in-flight if it is not a processed duplicate.
+func (c *dingTalkChannel) beginMessage(dedupKey string) bool {
+	now := time.Now()
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.pruneMessageCacheLocked(now)
+	if _, ok := c.processed[dedupKey]; ok {
+		return false
+	}
+	if _, ok := c.inflight[dedupKey]; ok {
+		return false
+	}
+	c.inflight[dedupKey] = now
+	return true
+}
+
+// finishMessage moves a DingTalk message from in-flight to processed after handling.
+func (c *dingTalkChannel) finishMessage(dedupKey string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	delete(c.inflight, dedupKey)
+	c.processed[dedupKey] = time.Now()
+}
+
+// cancelInflight removes an in-flight duplicate key when enqueue fails.
+func (c *dingTalkChannel) cancelInflight(dedupKey string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	delete(c.inflight, dedupKey)
+}
+
+// pruneMessageCacheLocked removes expired duplicate-tracking entries while c.mu is held.
+func (c *dingTalkChannel) pruneMessageCacheLocked(now time.Time) {
+	cutoff := now.Add(-dingTalkMessageTTL)
+	for key, ts := range c.processed {
+		if ts.Before(cutoff) {
+			delete(c.processed, key)
+		}
+	}
+	for key, ts := range c.inflight {
+		if ts.Before(cutoff) {
+			delete(c.inflight, key)
+		}
+	}
+}
+
+// saveSessionWebhook caches the DingTalk reply webhook for one conversation.
+func (c *dingTalkChannel) saveSessionWebhook(chatID, sessionWebhook string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.sessionWebhooks[chatID] = sessionWebhook
+}
+
+// postWebhook posts a markdown reply payload to a DingTalk sessionWebhook.
+func (c *dingTalkChannel) postWebhook(ctx context.Context, sessionWebhook string, payload map[string]any) error {
+	body, _ := json.Marshal(payload)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, sessionWebhook, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(io.LimitReader(resp.Body, 1024*1024))
+	if resp.StatusCode >= 400 {
+		return fmt.Errorf("dingtalk reply status: %d, response: %s", resp.StatusCode, string(respBody))
+	}
+	return nil
+}
+
+// dingTalkExtractText extracts user text from DingTalk message payload variants.
+func dingTalkExtractText(data map[string]any) string {
+	text := data["text"]
+	if textMap := dingTalkMap(text); len(textMap) > 0 {
+		if content := dingTalkString(textMap["content"]); content != "" {
+			return content
+		}
+	}
+	if content := dingTalkString(text); content != "" {
+		return content
+	}
+
+	content := data["content"]
+	if contentMap := dingTalkMap(content); len(contentMap) > 0 {
+		for _, key := range []string{"text", "content", "recognition"} {
+			if value := dingTalkString(contentMap[key]); strings.TrimSpace(value) != "" {
+				return value
+			}
+		}
+	}
+	return dingTalkString(content)
+}
+
+// dingTalkBotDedupKey builds a stable duplicate key for a DingTalk bot callback payload.
+func dingTalkBotDedupKey(data *chatbot.BotCallbackDataModel, text string) string {
+	if data == nil {
+		return ""
+	}
+	if data.MsgId != "" {
+		return "msg:" + data.MsgId
+	}
+	if data.ConversationId != "" && dingTalkFirstNonEmpty(data.SenderId, data.SenderStaffId) != "" && strings.TrimSpace(text) != "" {
+		sum := sha1.Sum([]byte(text))
+		eventTS := ""
+		if data.CreateAt > 0 {
+			eventTS = ":" + strconv.FormatInt(data.CreateAt, 10)
+		}
+		return fmt.Sprintf("fallback:%s:%s%s:%s", data.ConversationId, dingTalkFirstNonEmpty(data.SenderId, data.SenderStaffId), eventTS, hex.EncodeToString(sum[:])[:16])
+	}
+	return ""
+}
+
+// dingTalkDurationSeconds converts a config value measured in seconds to a duration.
+func dingTalkDurationSeconds(value any) time.Duration {
+	switch v := value.(type) {
+	case int:
+		return time.Duration(v) * time.Second
+	case int64:
+		return time.Duration(v) * time.Second
+	case float64:
+		return time.Duration(v) * time.Second
+	case json.Number:
+		n, err := v.Int64()
+		if err != nil {
+			return 0
+		}
+		return time.Duration(n) * time.Second
+	case string:
+		n, err := strconv.Atoi(strings.TrimSpace(v))
+		if err != nil {
+			return 0
+		}
+		return time.Duration(n) * time.Second
+	default:
+		return 0
+	}
+}
+
+// dingTalkString converts common JSON values to strings.
+func dingTalkString(value any) string {
+	text := strings.TrimSpace(fmt.Sprint(value))
+	if text == "" || text == "<nil>" {
+		return ""
+	}
+	return text
+}
+
+// dingTalkMap returns value as a string-keyed map when possible.
+func dingTalkMap(value any) map[string]any {
+	if out, ok := value.(map[string]any); ok {
+		return out
+	}
+	return map[string]any{}
+}
+
+// dingTalkFirstNonEmpty returns the first non-empty string.
+func dingTalkFirstNonEmpty(values ...string) string {
+	for _, value := range values {
+		if strings.TrimSpace(value) != "" {
+			return strings.TrimSpace(value)
+		}
+	}
+	return ""
+}
diff --git a/internal/channels/dingtalk_test.go b/internal/channels/dingtalk_test.go
new file mode 100644
index 0000000000..3906b9bf55
--- /dev/null
+++ b/internal/channels/dingtalk_test.go
@@ -0,0 +1,165 @@
+//
+//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+package channels
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/open-dingtalk/dingtalk-stream-sdk-go/chatbot"
+
+	"ragflow/internal/channels/core"
+)
+
+func TestNewDingTalkChannelFromConfigRequiresCredentials(t *testing.T) {
+	if _, err := newDingTalkChannelFromConfig("account-1", map[string]any{"client_id": "client-1"}); err == nil {
+		t.Fatal("newDingTalkChannelFromConfig succeeded without client_secret")
+	}
+}
+
+func TestNewDingTalkChannelFromConfigNormalizesConfig(t *testing.T) {
+	ch, err := newDingTalkChannelFromConfig("account-1", map[string]any{
+		"clientId":     "client-1",
+		"clientSecret": "secret-1",
+		"api_base_url": "https://dingtalk.example",
+		"timeout_secs": "7",
+	})
+	if err != nil {
+		t.Fatalf("newDingTalkChannelFromConfig returned error: %v", err)
+	}
+	if ch.account.ClientID != "client-1" {
+		t.Fatalf("client id = %q, want client-1", ch.account.ClientID)
+	}
+	if ch.account.ClientSecret != "secret-1" {
+		t.Fatalf("client secret = %q, want secret-1", ch.account.ClientSecret)
+	}
+	if ch.account.APIBaseURL != "https://dingtalk.example" {
+		t.Fatalf("api base url = %q, want https://dingtalk.example", ch.account.APIBaseURL)
+	}
+	if ch.account.Timeout != 7*time.Second {
+		t.Fatalf("timeout = %s, want 7s", ch.account.Timeout)
+	}
+}
+
+func TestDingTalkExtractText(t *testing.T) {
+	tests := []struct {
+		name string
+		data map[string]any
+		want string
+	}{
+		{name: "text object", data: map[string]any{"text": map[string]any{"content": "hello"}}, want: "hello"},
+		{name: "text string", data: map[string]any{"text": "hello"}, want: "hello"},
+		{name: "content object text", data: map[string]any{"content": map[string]any{"text": "hello"}}, want: "hello"},
+		{name: "content object recognition", data: map[string]any{"content": map[string]any{"recognition": "hello"}}, want: "hello"},
+		{name: "content string", data: map[string]any{"content": "hello"}, want: "hello"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := dingTalkExtractText(tt.data); got != tt.want {
+				t.Fatalf("dingTalkExtractText() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDingTalkBotDedupKey(t *testing.T) {
+	if got := dingTalkBotDedupKey(&chatbot.BotCallbackDataModel{MsgId: "msg-1"}, "hello"); got != "msg:msg-1" {
+		t.Fatalf("dedup key = %q, want msg:msg-1", got)
+	}
+
+	got := dingTalkBotDedupKey(&chatbot.BotCallbackDataModel{
+		ConversationId: "conv-1",
+		SenderId:       "sender-1",
+		CreateAt:       1000,
+	}, "hello")
+	if got != "fallback:conv-1:sender-1:1000:aaf4c61ddcc5e8a2" {
+		t.Fatalf("fallback dedup key = %q", got)
+	}
+}
+
+func TestDingTalkNormalizeBotMessage(t *testing.T) {
+	ch := newDingTalkChannel(dingTalkAccount{AccountID: "account-1", ClientID: "client-1", ClientSecret: "secret-1"})
+
+	incoming, dedupKey, ok := ch.normalizeBotMessage(&chatbot.BotCallbackDataModel{
+		ConversationId:   "chat-1",
+		ConversationType: "2",
+		MsgId:            "msg-1",
+		SenderId:         "sender-1",
+		SessionWebhook:   "https://webhook.example",
+		Text:             chatbot.BotCallbackDataTextModel{Content: "hello"},
+	})
+	if !ok {
+		t.Fatal("normalizeBotMessage failed")
+	}
+	if incoming.Channel != "dingtalk" || incoming.AccountID != "account-1" || incoming.ChatID != "chat-1" || incoming.MessageID != "msg-1" || incoming.SenderID != "sender-1" || incoming.Text != "hello" {
+		t.Fatalf("unexpected incoming message: %+v", incoming)
+	}
+	if dedupKey != "msg:msg-1" {
+		t.Fatalf("dedup key = %q, want msg:msg-1", dedupKey)
+	}
+	if ch.sessionWebhooks["chat-1"] != "https://webhook.example" {
+		t.Fatal("sessionWebhook was not cached")
+	}
+}
+
+func TestDingTalkSendUsesCachedSessionWebhook(t *testing.T) {
+	requestBody := map[string]any{}
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err := json.NewDecoder(r.Body).Decode(&requestBody); err != nil {
+			t.Errorf("decode body: %v", err)
+			return
+		}
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer server.Close()
+
+	ch := newDingTalkChannel(dingTalkAccount{AccountID: "account-1", ClientID: "client-1", ClientSecret: "secret-1"})
+	ch.sessionWebhooks["chat-1"] = server.URL
+
+	err := ch.Send(context.Background(), core.OutgoingMessage{ChatID: "chat-1", Text: "hello"})
+	if err != nil {
+		t.Fatalf("Send returned error: %v", err)
+	}
+	if requestBody["msgtype"] != "markdown" {
+		t.Fatalf("msgtype = %v, want markdown", requestBody["msgtype"])
+	}
+}
+
+func TestDingTalkEnqueueFailureCancelsInflight(t *testing.T) {
+	ch := newDingTalkChannel(dingTalkAccount{AccountID: "account-1", ClientID: "client-1", ClientSecret: "secret-1"})
+	worker := &dingTalkWorker{queue: make(chan dingTalkQueuedMessage, 1)}
+	worker.queue <- dingTalkQueuedMessage{incoming: core.IncomingMessage{MessageID: "queued"}}
+	ch.workers["chat-1"] = worker
+	ch.inflight["msg:drop"] = time.Now()
+
+	ok := ch.enqueueIncoming(context.Background(), dingTalkQueuedMessage{
+		incoming: core.IncomingMessage{ChatID: "chat-1", MessageID: "drop"},
+		dedupKey: "msg:drop",
+	})
+	if ok {
+		t.Fatal("enqueueIncoming succeeded for a full queue")
+	}
+	ch.cancelInflight("msg:drop")
+	if _, exists := ch.inflight["msg:drop"]; exists {
+		t.Fatal("inflight key remains after enqueue failure")
+	}
+}