diff --git a/zeusd/Cargo.toml b/zeusd/Cargo.toml
index c5d66cce..cfa294d6 100644
--- a/zeusd/Cargo.toml
+++ b/zeusd/Cargo.toml
@@ -20,7 +20,7 @@ name = "zeusd"
 [dependencies]
 nvml-wrapper = "0.10"
 actix-web = "4"
-tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
+tokio = { version = "1", features = ["macros", "rt-multi-thread", "fs"] }
 thiserror = "1"
 clap = { version = "4.5.4", features = ["derive"] }
 serde = { version = "1", features = ["derive"] }
diff --git a/zeusd/src/devices/cpu/mod.rs b/zeusd/src/devices/cpu/mod.rs
new file mode 100644
index 00000000..5d71a3e8
--- /dev/null
+++ b/zeusd/src/devices/cpu/mod.rs
@@ -0,0 +1,47 @@
+//! CPU power measurement with RAPL. Only supported on Linux.
+
+use std::io::Read;
+
+use tokio::io::AsyncReadExt;
+
+pub struct FieldInfo {
+    pub name: String,
+    pub max_energy_uj: f64,
+}
+
+pub trait CpuManager {
+    fn get_available_fields(&self) -> Vec<FieldInfo>;
+    fn get_field_energy(&self, field_name: &str) -> f64;
+}
+
+static RAPL_DIR: &'static str = "/sys/class/powercap/intel-rapl";
+
+pub struct RAPLCpuManager {
+    fields: Vec<FieldInfo>,
+}
+
+impl RAPLCpuManager {
+    pub fn new() -> Self {
+        let mut fields = Vec::with_capacity(2);
+
+        // The package domain is always present
+
+        // Look for subdomains and add to fields
+
+        Self { fields }
+    }
+}
+
+fn read_u64(path: &std::path::Path) -> f64 {
+    let mut file = std::fs::File::open(path).unwrap();
+    let mut buf = String::new();
+    file.read_to_string(&mut buf).unwrap();
+    buf.trim().parse().unwrap()
+}
+
+async fn read_u64_async(path: &std::path::Path) -> f64 {
+    let mut file = tokio::fs::File::open(path).await.unwrap();
+    let mut buf = String::new();
+    file.read_to_string(&mut buf).await.unwrap();
+    buf.trim().parse().unwrap()
+}
diff --git a/zeusd/src/devices/mod.rs b/zeusd/src/devices/mod.rs
index eaeb673a..d1010fa9 100644
--- a/zeusd/src/devices/mod.rs
+++ b/zeusd/src/devices/mod.rs
@@ -1,3 +1,4 @@
 //! Interfaces for interacting with devices
 
 pub mod gpu;
+pub mod cpu;
diff --git a/zeusd/src/routes/gpu.rs b/zeusd/src/routes/gpu.rs
index b0d5bf75..ec0ce50b 100644
--- a/zeusd/src/routes/gpu.rs
+++ b/zeusd/src/routes/gpu.rs
@@ -13,7 +13,7 @@ use crate::error::ZeusdError;
 /// This macro takes
 /// - the API name (set_power_limit, set_persistence_mode, etc.),
 /// - the method and path for the request handler,
-/// - and a list of `field name <type>` pairs of the corresponding `GpuCommand` variant.
+/// - and a list of `field name: type` pairs of the corresponding `GpuCommand` variant.
 ///
 /// Gien this, the macro generates
 /// - a request payload struct named API name (e.g., SetPowerLimit) and all the