diff --git a/test/types/index.test-d.ts b/test/types/index.test-d.ts
index 83c982af..e6bad0ad 100644
--- a/test/types/index.test-d.ts
+++ b/test/types/index.test-d.ts
@@ -7,6 +7,7 @@ const NODE_NAME = 'test_node';
 const LIFECYCLE_NODE_NAME = 'lifecycle_test_node';
 const TYPE_CLASS = 'std_msgs/msg/String';
 const TOPIC = 'topic';
+const SERVICE_NAME = 'service';
 const MSG = rclnodejs.createMessageObject(TYPE_CLASS);
 MSG.data = '';
 
@@ -27,6 +28,7 @@ expectType<string | undefined>(rclnodejs.DistroUtils.getDistroName(2105));
 
 // ---- Context -----
 expectType<rclnodejs.Context>(rclnodejs.Context.defaultContext());
+expectType<number>(rclnodejs.Context.defaultContext().domainId());
 
 // ---- NodeOptions ----
 const nodeOptions = new rclnodejs.NodeOptions();
@@ -69,6 +71,8 @@ expectType<Array<object>>(node.getPublishersInfoByTopic('topic', false));
 expectType<Array<object>>(node.getSubscriptionsInfoByTopic('topic', false));
 expectType<number>(node.countPublishers(TOPIC));
 expectType<number>(node.countSubscribers(TOPIC));
+expectType<number>(node.countClients(SERVICE_NAME));
+expectType<number>(node.countServices(SERVICE_NAME));
 expectType<rclnodejs.Options<string | rclnodejs.QoS>>(
   rclnodejs.Node.getDefaultOptions()
 );
@@ -229,6 +233,9 @@ expectType<bigint>(timer.timeSinceLastCall());
 expectType<bigint>(timer.timeUntilNextCall());
 expectType<boolean>(timer.isCanceled());
 expectType<void>(timer.cancel());
+expectType<void>(timer.changeTimerPeriod(BigInt(100000)));
+expectType<bigint>(timer.timerPeriod());
+expectType<object>(timer.callTimerWithInfo());
 
 // ---- Rate ----
 const rate = await node.createRate(1);
diff --git a/types/context.d.ts b/types/context.d.ts
index 38292463..07a73b17 100644
--- a/types/context.d.ts
+++ b/types/context.d.ts
@@ -87,5 +87,11 @@ declare module 'rclnodejs' {
      * @returns The default Context
      */
     static defaultContext(): Context;
+
+    /**
+     * Get the domain ID of this context.
+     * @returns domain ID of this context
+     */
+    domainId(): number;
   }
 }
diff --git a/types/node.d.ts b/types/node.d.ts
index 5eeab78f..89d5c6c7 100644
--- a/types/node.d.ts
+++ b/types/node.d.ts
@@ -782,5 +782,19 @@ declare module 'rclnodejs' {
      * @returns Number of subscribers on the given topic.
      */
     countSubscribers(topic: string): number;
+
+    /**
+     * Get the number of clients on a given service name.
+     * @param serviceName - The service name.
+     * @returns Number of clients.
+     */
+    countClients(serviceName: string): number;
+
+    /**
+     * Get the number of services  on a given service name.
+     * @param serviceName - The service name.
+     * @returns Number of services.
+     */
+    countServices(serviceName: string): number;
   }
 }
diff --git a/types/publisher.d.ts b/types/publisher.d.ts
index 89fe12f7..d849925a 100644
--- a/types/publisher.d.ts
+++ b/types/publisher.d.ts
@@ -14,5 +14,11 @@ declare module 'rclnodejs' {
      * @param message - The message to be sent.
      */
     publish(message: MessageType<T> | Buffer): void;
+
+    /**
+     * Get the number of subscriptions to this publisher.
+     * @returns The number of subscriptions
+     */
+    subscriptionCount(): number;
   }
 }
diff --git a/types/subscription.d.ts b/types/subscription.d.ts
index a0a41c9b..5e28c37a 100644
--- a/types/subscription.d.ts
+++ b/types/subscription.d.ts
@@ -66,5 +66,11 @@ declare module 'rclnodejs' {
      * @returns True if successful; false otherwise
      */
     clearContentFilter(): boolean;
+
+    /**
+     * Get the number of publishers to this subscription.
+     * @returns The number of publishers
+     */
+    publisherCount(): number;
   }
 }
diff --git a/types/timer.d.ts b/types/timer.d.ts
index 04f0f880..8fc73f58 100644
--- a/types/timer.d.ts
+++ b/types/timer.d.ts
@@ -45,5 +45,23 @@ declare module 'rclnodejs' {
      * @returns The interval value in nanoseconds
      */
     timeUntilNextCall(): bigint;
+
+    /**
+     * Change the timer period.
+     * @param period - The new period in nanoseconds.
+     */
+    changeTimerPeriod(period: bigint): void;
+
+    /**
+     * Get the timer period.
+     * @return The period in nanoseconds.
+     */
+    timerPeriod(): bigint;
+
+    /**
+     * Call a timer and starts counting again, retrieves actual and expected call time.
+     * @return - The timer information.
+     */
+    callTimerWithInfo(): object;
   }
 }