diff --git a/vibi-dpu/src/main.rs b/vibi-dpu/src/main.rs
index e7a11a96..31646959 100644
--- a/vibi-dpu/src/main.rs
+++ b/vibi-dpu/src/main.rs
@@ -1,3 +1,21 @@
-fn main() {
-    println!("Hello, world!");
-}
+use std::env;
+mod pubsub;
+// mod db;
+// mod core;
+// mod bitbucket;
+// mod utils;
+
+#[tokio::main]
+async fn main() {
+    // Get topic subscription and Listen to messages 
+    let gcp_credentials = //"/home/tapishr/dev-profiler/pubsub-sa.json".to_owned();
+    env::var("GCP_CREDENTIALS").expect("GCP_CREDENTIALS must be set");
+    let topic_name = //"rtapish-fromserver".to_owned();
+    env::var("INSTALL_ID").expect("INSTALL_ID must be set");
+    println!("env vars = {}, {}", &gcp_credentials, &topic_name);
+    
+    pubsub::listener::listen_messages(
+        &gcp_credentials, 
+        &topic_name,
+    ).await;
+}
\ No newline at end of file
diff --git a/vibi-dpu/src/pubsub/listener.rs b/vibi-dpu/src/pubsub/listener.rs
new file mode 100644
index 00000000..aac98777
--- /dev/null
+++ b/vibi-dpu/src/pubsub/listener.rs
@@ -0,0 +1,121 @@
+use std::collections::HashMap;
+
+use futures_util::StreamExt;
+use google_cloud_auth::credentials::CredentialsFile;
+use google_cloud_default::WithAuthExt;
+use google_cloud_pubsub::{
+    client::{Client, ClientConfig},
+    subscription::{SubscriptionConfig, Subscription},
+};
+use serde::Deserialize;
+use tokio::task;
+use std::collections::VecDeque;
+use sha256::digest;
+use tonic::Code;
+// use crate::core::{setup::handle_install_bitbucket, review::process_review}; // To be added in future PR
+
+#[derive(Debug, Deserialize)]
+struct InstallCallback {
+    repository_provider: String,
+    installation_code: String,
+}
+
+
+async fn process_message(attributes: &HashMap<String, String>, data_bytes: &Vec<u8>) {
+    let msgtype_opt = attributes.get("msgtype");
+    if msgtype_opt.is_none() {
+        eprintln!("msgtype attribute not found in message : {:?}", attributes);
+        return;
+    }
+    let msgtype = msgtype_opt.expect("Empty msgtype");
+    match msgtype.as_str() {
+        "install_callback" => {
+            println!("Processing install callback message");
+            let msg_data_res =  serde_json::from_slice::<InstallCallback>(data_bytes);
+            if msg_data_res.is_err() {
+                eprintln!("Error deserializing install callback: {:?}", msg_data_res);
+                return;
+            }
+            let data = msg_data_res.expect("msg_data not found");
+            let code_async = data.installation_code.clone();
+            task::spawn(async move {
+                // handle_install_bitbucket(&code_async).await;
+                println!("Processed install callback message");
+            });
+        },
+        "webhook_callback" => {
+            task::spawn(async move {
+                // process_review(&data_bytes).await;
+                println!("Processed webhook callback message");
+            });
+        }
+        _ => {
+            eprintln!("Message type not found for message : {:?}", attributes);
+        }
+    };
+}
+
+pub async fn get_pubsub_client_config(keypath: &str) -> ClientConfig {
+    let credfile = CredentialsFile::new_from_file(keypath.to_string()).await
+        .expect("Failed to locate credentials file");
+    return ClientConfig::default()
+        .with_credentials(credfile)
+        .await
+        .expect("Unable to get PubSub Client config");
+}
+
+async fn setup_subscription(keypath: &str, topicname: &str) -> Subscription{
+    let config = get_pubsub_client_config(keypath).await;
+    let client = Client::new(config).await
+        .expect("Unable to create pubsub client to listen to messages");
+    let topic = client.topic(topicname);
+    let topic_res = topic.exists(None).await;
+    if topic_res.is_err() {
+        let e = topic_res.expect_err("No error found in topic_res");
+        if e.code() == Code::NotFound {
+            client.create_topic(topicname, None, None).await
+                .expect("Unable to create topic");
+        }
+        else {
+            eprintln!("Error getting topic: {:?}", e);
+        }
+    }
+    let sub_config = SubscriptionConfig {
+        enable_message_ordering: true,
+        ..Default::default()
+    };
+    let subscription_name = format!("{topicname}-sub");
+    let subscription = client.subscription(&subscriptionname);
+    if !subscription.exists(None).await.expect("Unable to get subscription information") {
+        subscription.create(
+            topic.fully_qualified_name(), subconfig, None)
+            .await.expect("Unable to create subscription for listening to messages");
+    }
+    println!("sub = {:?}", &subscription);
+    subscription
+}
+
+pub async fn listen_messages(keypath: &str, topicname: &str) {
+    let queue_cap = 100;
+    let mut message_hashes = VecDeque::with_capacity(queue_cap);
+    let subscription = setup_subscription(keypath, topicname).await;
+    let mut stream = subscription.subscribe(None).await
+        .expect("Unable to subscribe to messages");
+    while let Some(message) = stream.next().await {
+        println!("Listening for messages...");
+        let attrmap: HashMap<String, String> = message.message.attributes.clone().into_iter().collect();
+        let message_hash = digest(&*message.message.data);
+        if !message_hashes.contains(&message_hash) {
+            message_hashes.push_back(message_hash);
+            if message_hashes.len() > queue_cap {
+                while message_hashes.len() > queue_cap {
+                    message_hashes.pop_front();
+                }
+            }
+            let msg_bytes = message.message.data.clone();
+            process_message(&attrmap, &msg_bytes).await;
+        }
+        // Ack or Nack message.
+        let _ = message.ack().await;
+    }
+}
\ No newline at end of file
diff --git a/vibi-dpu/src/pubsub/mod.rs b/vibi-dpu/src/pubsub/mod.rs
new file mode 100644
index 00000000..baefb0b9
--- /dev/null
+++ b/vibi-dpu/src/pubsub/mod.rs
@@ -0,0 +1 @@
+pub mod listener;
\ No newline at end of file