diff --git a/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/ErrorMonitor.kt b/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/ErrorMonitor.kt
new file mode 100644
index 000000000..e5d967a86
--- /dev/null
+++ b/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/ErrorMonitor.kt
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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 com.google.samples.apps.nowinandroid.core.data.util
+
+import com.google.samples.apps.nowinandroid.core.model.data.MessageData
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Interface for handling messages.
+ */
+interface ErrorMonitor {
+    fun addMessageByString(message: String): MessageData
+
+    fun addMessageByData(message: MessageData)
+
+    fun clearMessage(message: MessageData)
+
+    fun clearAllMessages()
+
+    val messages: Flow<List<MessageData?>>
+}
diff --git a/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/StateErrorMonitor.kt b/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/StateErrorMonitor.kt
new file mode 100644
index 000000000..76efe3e37
--- /dev/null
+++ b/core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/util/StateErrorMonitor.kt
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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 com.google.samples.apps.nowinandroid.core.data.util
+
+import com.google.samples.apps.nowinandroid.core.model.data.MessageData
+import com.google.samples.apps.nowinandroid.core.model.data.MessageType
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.update
+import javax.inject.Inject
+
+/**
+ * Interface implementation for handling general errors.
+ */
+
+class StateErrorMonitor @Inject constructor() : ErrorMonitor {
+    /**
+     * List of [MessageData] to be shown
+     */
+    override val messages = MutableStateFlow<List<MessageData>>(emptyList())
+
+    /**
+     * Creates a [MessageData] and adds it to the list.
+     * @param message: String value for message to add.
+     */
+    override fun addMessageByString(message: String): MessageData {
+        val data = MessageData(type = MessageType.MESSAGE(message))
+        messages.update { it + data }
+
+        return data
+    }
+
+    /**
+     * Add a [MessageData] to the list.
+     * @param message: [MessageData] to add.
+     */
+    override fun addMessageByData(message: MessageData) {
+        messages.update { it + message }
+    }
+
+    /**
+     * Removes the [MessageData] from the list.
+     */
+    override fun clearMessage(message: MessageData) {
+        messages.update { list -> list.filterNot { it == message } }
+    }
+
+    /**
+     * Remove all from list, reset to empty list
+     */
+    override fun clearAllMessages() {
+        messages.update { emptyList() }
+    }
+}
diff --git a/core/model/src/main/kotlin/com/google/samples/apps/nowinandroid/core/model/data/MessageData.kt b/core/model/src/main/kotlin/com/google/samples/apps/nowinandroid/core/model/data/MessageData.kt
new file mode 100644
index 000000000..7fc5eb8f2
--- /dev/null
+++ b/core/model/src/main/kotlin/com/google/samples/apps/nowinandroid/core/model/data/MessageData.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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 com.google.samples.apps.nowinandroid.core.model.data
+
+/**
+ * [MessageData]
+ * Class to hold messages type objects with actions
+ */
+data class MessageData(
+    val type: MessageType,
+    val label: String? = null,
+    val onConfirm: (() -> Unit)? = null,
+    val onDelay: (() -> Unit)? = null,
+)
+
+/**
+ * Specified Errors
+ */
+sealed class MessageType {
+    data object OFFLINE : MessageType()
+    data class MESSAGE(val value: String) : MessageType()
+    data object UNKNOWN : MessageType()
+}