diff --git a/Cargo.lock b/Cargo.lock
index b07f8af..494dc73 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2075,6 +2075,7 @@ dependencies = [
  "semver",
  "serde",
  "serde_json",
+ "serde_yaml",
  "sha1",
  "sha2",
  "tempfile",
@@ -3237,6 +3238,19 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_yaml"
+version = "0.9.34+deprecated"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a8b1a1a2ebf674015cc02edccce75287f1a0130d394307b36743c2f5d504b47"
+dependencies = [
+ "indexmap",
+ "itoa",
+ "ryu",
+ "serde",
+ "unsafe-libyaml",
+]
+
 [[package]]
 name = "sha1"
 version = "0.10.6"
@@ -3923,6 +3937,12 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "229730647fbc343e3a80e463c1db7f78f3855d3f3739bee0dda773c9a037c90a"
 
+[[package]]
+name = "unsafe-libyaml"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "673aac59facbab8a9007c7f6108d11f63b603f7cabff99fabf650fea5c32b861"
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"
diff --git a/mcmpmgr/Cargo.toml b/mcmpmgr/Cargo.toml
index 0761b3f..492896d 100644
--- a/mcmpmgr/Cargo.toml
+++ b/mcmpmgr/Cargo.toml
@@ -14,6 +14,7 @@ reqwest = { version = "0.12.5", features = ["json"] }
 semver = { version = "1.0.23", features = ["serde"] }
 serde = { version = "1.0.207", features = ["derive"] }
 serde_json = "1.0.128"
+serde_yaml = "0.9.34"
 sha1 = "0.10.6"
 sha2 = "0.10.8"
 tempfile = "3.12.0"
diff --git a/mcmpmgr/src/file_merge.rs b/mcmpmgr/src/file_merge.rs
index b462962..03efaa9 100644
--- a/mcmpmgr/src/file_merge.rs
+++ b/mcmpmgr/src/file_merge.rs
@@ -1,4 +1,4 @@
-use std::{any::Any, default, str::FromStr};
+use std::str::FromStr;
 
 #[derive(Debug, Clone, Copy)]
 pub enum FileType {
@@ -81,50 +81,164 @@ fn test_merge_json() {
 
     assert!(
         merged_overwrite["b"]["y"]["test"] == "thing",
-        "//b/y/test wasn't overwritten with \"thing\". src={}, dst={}",
+        "//b/y/test wasn't overwritten with \"thing\". src={:#?}, dst={:#?}",
         src,
         merged_overwrite
     );
     assert!(
         merged_overwrite["a"] == 3,
-        "//a was not set to 3. src={}, dst={}",
+        "//a was not set to 3. src={:#?}, dst={:#?}",
         src,
         merged_overwrite
     );
     assert!(
         merged_overwrite["b"]["x"].is_object(),
-        "//b/x is not an object. src={}, dst={}",
+        "//b/x is not an object. src={:#?}, dst={:#?}",
         src,
         merged_overwrite
     );
     assert!(
         merged_overwrite["c"]["foo"] == "bar",
-        "//c/foo != bar. src={}, dst={}",
+        "//c/foo != bar. src={:#?}, dst={:#?}",
         src,
         merged_overwrite
     );
 
     assert!(
         merged_retained["b"]["y"]["test"] == "something",
-        "//b/y/test was overwritten. src={}, dst={}",
+        "//b/y/test was overwritten. src={:#?}, dst={:#?}",
         src,
         merged_retained
     );
     assert!(
         merged_retained["a"] == 3,
-        "//a was not set to 3. src={}, dst={}",
+        "//a was not set to 3. src={:#?}, dst={:#?}",
         src,
         merged_retained
     );
     assert!(
         merged_retained["b"]["x"].is_object(),
-        "//b/x is not an object. src={}, dst={}",
+        "//b/x is not an object. src={:#?}, dst={:#?}",
         src,
         merged_retained
     );
     assert!(
         merged_retained["c"]["foo"] == "bar",
-        "//c/foo != bar. src={}, dst={}",
+        "//c/foo != bar. src={:#?}, dst={:#?}",
+        src,
+        merged_retained
+    );
+}
+
+fn merge_yaml(
+    src: &serde_yaml::Value,
+    dst: &mut serde_yaml::Value,
+    overwrite_existing: bool,
+) -> anyhow::Result<()> {
+    if src.is_mapping() && dst.is_mapping() {
+        let src = src.as_mapping().unwrap();
+        let dst = dst.as_mapping_mut().unwrap();
+
+        for (k, v) in src.iter() {
+            if v.is_mapping() {
+                let dst_v = dst.entry(k.clone()).or_insert(serde_yaml::from_str("{}")?);
+                merge_yaml(v, dst_v, overwrite_existing)?;
+            } else {
+                if overwrite_existing || !dst.contains_key(k) {
+                    dst.insert(k.clone(), v.clone());
+                }
+            }
+        }
+    } else {
+        // TODO: Keep track of path for better errors
+        anyhow::bail!("Cannot merge non-objects: {src:#?} and {dst:#?}")
+    }
+    Ok(())
+}
+
+#[test]
+fn test_merge_yaml() {
+    let src = serde_yaml::from_str(
+        r#"{
+        "a": 3,
+        "b": {
+            "x": {
+
+            },
+            "y": {
+                "test": "thing"
+            }
+        },
+        "c": {}
+    }"#,
+    )
+    .unwrap();
+
+    let dst: serde_yaml::Value = serde_yaml::from_str(
+        r#"{
+        "b": {
+            "y": {
+                "test": "something"
+            }
+        },
+        "c": {
+            "foo": "bar"
+        }
+    }"#,
+    )
+    .unwrap();
+
+    let mut merged_overwrite = dst.clone();
+    let mut merged_retained = dst.clone();
+    merge_yaml(&src, &mut merged_overwrite, true).unwrap();
+    merge_yaml(&src, &mut merged_retained, false).unwrap();
+
+    assert!(
+        merged_overwrite["b"]["y"]["test"] == "thing",
+        "//b/y/test wasn't overwritten with \"thing\". src={:#?}, dst={:#?}",
+        src,
+        merged_overwrite
+    );
+    assert!(
+        merged_overwrite["a"] == 3,
+        "//a was not set to 3. src={:#?}, dst={:#?}",
+        src,
+        merged_overwrite
+    );
+    assert!(
+        merged_overwrite["b"]["x"].is_mapping(),
+        "//b/x is not a mapping. src={:#?}, dst={:#?}",
+        src,
+        merged_overwrite
+    );
+    assert!(
+        merged_overwrite["c"]["foo"] == "bar",
+        "//c/foo != bar. src={:#?}, dst={:#?}",
+        src,
+        merged_overwrite
+    );
+
+    assert!(
+        merged_retained["b"]["y"]["test"] == "something",
+        "//b/y/test was overwritten. src={:#?}, dst={:#?}",
+        src,
+        merged_retained
+    );
+    assert!(
+        merged_retained["a"] == 3,
+        "//a was not set to 3. src={:#?}, dst={:#?}",
+        src,
+        merged_retained
+    );
+    assert!(
+        merged_retained["b"]["x"].is_mapping(),
+        "//b/x is not a mapping. src={:#?}, dst={:#?}",
+        src,
+        merged_retained
+    );
+    assert!(
+        merged_retained["c"]["foo"] == "bar",
+        "//c/foo != bar. src={:#?}, dst={:#?}",
         src,
         merged_retained
     );
@@ -144,7 +258,12 @@ fn merge_files(
             merge_json(&src_val, &mut dst_val, overwrite_existing)?;
             dst_val.to_string()
         }
-        FileType::Yaml => todo!(),
+        FileType::Yaml => {
+            let src_val = serde_yaml::Value::from(src);
+            let mut dst_val = serde_yaml::Value::from(dst);
+            merge_yaml(&src_val, &mut dst_val, overwrite_existing)?;
+            serde_yaml::to_string(&dst_val)?
+        }
         FileType::Toml => todo!(),
     })
 }