diff --git a/Cargo.lock b/Cargo.lock
index 9110d72..0c1980b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -329,7 +329,7 @@ dependencies = [
 [[package]]
 name = "hpk-package"
 version = "0.1.0"
-source = "git+https://git.hitchhiker-linux.org/jeang3nie/hpk-package#9cf9d469f644c43ee2c2d9ca3b16e669c2def944"
+source = "git+https://git.hitchhiker-linux.org/jeang3nie/hpk-package#723d697e9085a575c1f6d59baf1e79819452d747"
 dependencies = [
  "chrono",
  "deku",
@@ -348,6 +348,7 @@ version = "0.1.0"
 dependencies = [
  "hpk-package",
  "rayon",
+ "serde",
  "url",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index e048696..d4b21a4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,4 +12,5 @@ server = []
 [dependencies]
 hpk-package = { git = "https://git.hitchhiker-linux.org/jeang3nie/hpk-package" }
 rayon = "1.7"
+serde = { version = "1.0.159", features = ["derive"] }
 url = "2.3.1"
diff --git a/src/client.rs b/src/client.rs
index 0799a9b..f3b7a29 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -1,20 +1,9 @@
-pub trait Client {
-    type Error;
-    type Response;
+use crate::Request;
 
-    fn get() -> Result<Self, Self::Error> where Self: Sized;
-    fn request(&self) -> Result<Self::Response, Self::Error>;
+pub fn make_request(request: Request) {
+    unimplemented!();
 }
 
-impl Client for super::Update {
-    type Error = Box<dyn std::error::Error>;
-    type Response = ();
-
-    fn get() -> Result<Self, Self::Error> {
-        unimplemented!();
-    }
-
-    fn request(&self) -> Result<Self::Response, Self::Error> {
-        unimplemented!();
-    }
+pub fn handle_response() {
+    unimplemented!();
 }
diff --git a/src/lib.rs b/src/lib.rs
index b774e49..fff3e48 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,89 @@
-use std::path::PathBuf;
+use hpk_package::{Arch, Package, Version};
+use serde::{Deserialize, Serialize};
+use std::{fmt, path::PathBuf};
 
 #[cfg(feature = "client")]
-mod client;
-#[cfg(feature = "client")]
-pub use client::Client;
+pub mod client;
 
 #[cfg(feature = "server")]
 pub mod server;
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct PackageSpec {
+    name: String,
+    version: Version,
+    arch: Arch,
+    release: u8,
+}
+
+impl fmt::Display for PackageSpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{}-{}_{}_{}",
+            self.name, self.version, self.arch, self.release
+        )
+    }
+}
+
+impl From<Package> for PackageSpec {
+    fn from(value: Package) -> Self {
+        Self {
+            name: value.name,
+            version: value.version,
+            arch: value.arch,
+            release: value.release,
+        }
+    }
+}
+
+impl From<&Package> for PackageSpec {
+    fn from(value: &Package) -> Self {
+        Self {
+            name: value.name.to_string(),
+            version: value.version.clone(),
+            arch: value.arch,
+            release: value.release,
+        }
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct Item {
-    pub package: String,
+    pub pspec: PackageSpec,
     pub path: PathBuf,
 }
 
-#[derive(Clone, Debug)]
-pub struct Update {
-    pub items: Vec<Item>,
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum Request {
+    Catalog,
+    Packages(Vec<PackageSpec>),
+    Updates(Vec<Item>),
+}
+
+impl From<Vec<PackageSpec>> for Request {
+    fn from(value: Vec<PackageSpec>) -> Self {
+        Self::Packages(value)
+    }
+}
+
+impl From<Vec<Item>> for Request {
+    fn from(value: Vec<Item>) -> Self {
+        Self::Updates(value)
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum ResponseHeader {
+    /// The server is sending it's catalog
+    Catalog,
+    /// The server is sending a package, captured value is it's length. A new header will be sent
+    /// for each subsequent file.
+    Package(usize),
+    /// The server is sending an archive of updated files
+    Updates,
+    /// One or more requested packages are not on the server
+    PackageNotFound(Vec<PackageSpec>),
+    /// One or more requested update files are not on the server
+    FileNotFound(Vec<Item>),
 }
diff --git a/src/server.rs b/src/server.rs
index e69de29..8b13789 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -0,0 +1 @@
+