diff --git a/src/mdns/dnssd_plat.hpp b/src/mdns/dnssd_plat.hpp
index 5b09b0b6aee..f075738dd73 100644
--- a/src/mdns/dnssd_plat.hpp
+++ b/src/mdns/dnssd_plat.hpp
@@ -45,6 +45,46 @@
 #include "mdns/mdns.hpp"
 #include "ncp/ncp_openthread.hpp"
 
+extern "C" otPlatDnssdState otPlatDnssdGetState(otInstance *aInstance);
+extern "C" void             otPlatDnssdRegisterService(otInstance                 *aInstance,
+                                                       const otPlatDnssdService   *aService,
+                                                       otPlatDnssdRequestId        aRequestId,
+                                                       otPlatDnssdRegisterCallback aCallback);
+extern "C" void             otPlatDnssdUnregisterService(otInstance                 *aInstance,
+                                                         const otPlatDnssdService   *aService,
+                                                         otPlatDnssdRequestId        aRequestId,
+                                                         otPlatDnssdRegisterCallback aCallback);
+extern "C" void             otPlatDnssdRegisterHost(otInstance                 *aInstance,
+                                                    const otPlatDnssdHost      *aHost,
+                                                    otPlatDnssdRequestId        aRequestId,
+                                                    otPlatDnssdRegisterCallback aCallback);
+extern "C" void             otPlatDnssdUnregisterHost(otInstance                 *aInstance,
+                                                      const otPlatDnssdHost      *aHost,
+                                                      otPlatDnssdRequestId        aRequestId,
+                                                      otPlatDnssdRegisterCallback aCallback);
+extern "C" void             otPlatDnssdRegisterKey(otInstance                 *aInstance,
+                                                   const otPlatDnssdKey       *aKey,
+                                                   otPlatDnssdRequestId        aRequestId,
+                                                   otPlatDnssdRegisterCallback aCallback);
+extern "C" void             otPlatDnssdUnregisterKey(otInstance                 *aInstance,
+                                                     const otPlatDnssdKey       *aKey,
+                                                     otPlatDnssdRequestId        aRequestId,
+                                                     otPlatDnssdRegisterCallback aCallback);
+extern "C" void otPlatDnssdStartServiceBrowser(otInstance *aInstance, const char *aServiceType, uint32_t aInfraIfIndex);
+extern "C" void otPlatDnssdStopServiceBrowser(otInstance *aInstance, const char *aServiceType, uint32_t aInfraIfIndex);
+extern "C" void otPlatDnssdStartServiceResolver(otInstance                       *aInstance,
+                                                const otPlatDnssdServiceInstance *aServiceInstance);
+extern "C" void otPlatDnssdStopServiceResolver(otInstance                       *aInstance,
+                                               const otPlatDnssdServiceInstance *aServiceInstance);
+extern "C" void otPlatDnssdStartIp6AddressResolver(otInstance *aInstance,
+                                                   const char *aHostName,
+                                                   uint32_t    aInfraIfIndex);
+extern "C" void otPlatDnssdStopIp6AddressResolver(otInstance *aInstance, const char *aHostName, uint32_t aInfraIfIndex);
+extern "C" void otPlatDnssdStartIp4AddressResolver(otInstance *aInstance,
+                                                   const char *aHostName,
+                                                   uint32_t    aInfraIfIndex);
+extern "C" void otPlatDnssdStopIp4AddressResolver(otInstance *aInstance, const char *aHostName, uint32_t aInfraIfIndex);
+
 namespace otbr {
 
 class BorderAgent;
@@ -57,13 +97,53 @@ class DnssdPlatform : private NonCopyable
 {
     friend class BorderAgent;
 
+    friend otPlatDnssdState otPlatDnssdGetState(otInstance *aInstance);
+    friend void             otPlatDnssdRegisterService(otInstance                 *aInstance,
+                                                       const otPlatDnssdService   *aService,
+                                                       otPlatDnssdRequestId        aRequestId,
+                                                       otPlatDnssdRegisterCallback aCallback);
+    friend void             otPlatDnssdUnregisterService(otInstance                 *aInstance,
+                                                         const otPlatDnssdService   *aService,
+                                                         otPlatDnssdRequestId        aRequestId,
+                                                         otPlatDnssdRegisterCallback aCallback);
+    friend void             otPlatDnssdRegisterHost(otInstance                 *aInstance,
+                                                    const otPlatDnssdHost      *aHost,
+                                                    otPlatDnssdRequestId        aRequestId,
+                                                    otPlatDnssdRegisterCallback aCallback);
+    friend void             otPlatDnssdUnregisterHost(otInstance                 *aInstance,
+                                                      const otPlatDnssdHost      *aHost,
+                                                      otPlatDnssdRequestId        aRequestId,
+                                                      otPlatDnssdRegisterCallback aCallback);
+    friend void             otPlatDnssdRegisterKey(otInstance                 *aInstance,
+                                                   const otPlatDnssdKey       *aKey,
+                                                   otPlatDnssdRequestId        aRequestId,
+                                                   otPlatDnssdRegisterCallback aCallback);
+    friend void             otPlatDnssdUnregisterKey(otInstance                 *aInstance,
+                                                     const otPlatDnssdKey       *aKey,
+                                                     otPlatDnssdRequestId        aRequestId,
+                                                     otPlatDnssdRegisterCallback aCallback);
+    friend void otPlatDnssdStartServiceBrowser(otInstance *aInstance, const char *aServiceType, uint32_t aInfraIfIndex);
+    friend void otPlatDnssdStopServiceBrowser(otInstance *aInstance, const char *aServiceType, uint32_t aInfraIfIndex);
+    friend void otPlatDnssdStartServiceResolver(otInstance                       *aInstance,
+                                                const otPlatDnssdServiceInstance *aServiceInstance);
+    friend void otPlatDnssdStopServiceResolver(otInstance                       *aInstance,
+                                               const otPlatDnssdServiceInstance *aServiceInstance);
+    friend void otPlatDnssdStartIp6AddressResolver(otInstance *aInstance,
+                                                   const char *aHostName,
+                                                   uint32_t    aInfraIfIndex);
+    friend void otPlatDnssdStopIp6AddressResolver(otInstance *aInstance, const char *aHostName, uint32_t aInfraIfIndex);
+    friend void otPlatDnssdStartIp4AddressResolver(otInstance *aInstance,
+                                                   const char *aHostName,
+                                                   uint32_t    aInfraIfIndex);
+    friend void otPlatDnssdStopIp4AddressResolver(otInstance *aInstance, const char *aHostName, uint32_t aInfraIfIndex);
+
 public:
     DnssdPlatform(Ncp::ControllerOpenThread &aNcp, Mdns::Publisher &aPublisher);
 
     void Start(void);
     void Stop(void);
 
-    //---------------------------------------
+private:
     typedef otPlatDnssdState            State;
     typedef otPlatDnssdService          Service;
     typedef otPlatDnssdHost             Host;
@@ -71,22 +151,21 @@ class DnssdPlatform : private NonCopyable
     typedef otPlatDnssdRequestId        RequestId;
     typedef otPlatDnssdRegisterCallback RegisterCallback;
 
+    // `otPlatDnssd` APIs
     State GetState(void) const { return mState; }
+    void  RegisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
+    void  UnregisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
+    void  RegisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
+    void  UnregisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
+    void  RegisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);
+    void  UnregisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);
 
-    void RegisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
-    void UnregisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
-    void RegisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
-    void UnregisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
-    void RegisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);
-    void UnregisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);
+    // Callback from BR agent
+    void HandleMdnsPublisherStateChange(Mdns::Publisher::State aState);
 
-private:
     static otError     ResultToError(otbrError aOtbrError);
     static std::string KeyNameFor(const Key &aKey);
 
-    // Callback from BR agent
-    void HandleMdnsPublisherStateChange(Mdns::Publisher::State aState);
-
     Mdns::Publisher::ResultCallback MakePublisherCallback(RequestId aRequestId, RegisterCallback aCallback);
 
     Ncp::ControllerOpenThread &mNcp;