diff --git a/Cargo.lock b/Cargo.lock
index 4863d20..641c30e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -51,6 +51,18 @@ checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 [[package]]
 name = "filecaster"
 version = "0.1.0"
+dependencies = [
+ "filecaster-derive",
+ "merge",
+ "serde",
+ "serde_json",
+ "tempfile",
+ "toml",
+]
+
+[[package]]
+name = "filecaster-derive"
+version = "0.1.0"
 dependencies = [
  "claims",
  "merge",
@@ -58,10 +70,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde",
- "serde_json",
  "syn",
- "tempfile",
- "toml",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 47bd27c..91175ac 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,40 +1,17 @@
-[package]
-name = "filecaster"
-version = "0.1.0"
-edition = "2024"
-authors = ["Kristofers Solo <dev@kristofers.xyz>"]
-description = "Procedural macro to derive configuration from files, with optional merging capabilities."
-repository = "https://github.com/kristoferssolo/filecaster"
-documentation = "https://docs.rs/filecaster"
-homepage = "https://github.com/kristoferssolo/filecaster"
-license = "MIT OR Apache-2.0"
-keywords = ["proc-macro", "derive", "configuration", "file-parsing"]
-categories = ["rust-patterns", "parsing", "config"]
-exclude = ["/.github", "/.gitignore", "/tests", "*.png", "*.md"]
-readme = "README.md"
+[workspace]
+resolver = "2"
+members = ["filecaster", "filecaster-derive"]
 
-[features]
-default = []
-merge = ["dep:merge"]
-
-[dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-proc-macro-error2 = "2.0"
-syn = { version = "2.0", features = ["extra-traits", "parsing"] }
+[workspace.dependencies]
 serde = { version = "1.0", features = ["derive"] }
-merge = { version = "0.2", optional = true }
-
-[dev-dependencies]
+merge = "0.2.0"
+# dev-dependencies
 claims = "0.8"
 serde_json = "1.0"
-tempfile = "3.20"
+tempfile = "3.10"
 toml = "0.9"
 
-[lib]
-proc-macro = true
-
-[lints.clippy]
+[workspace.lints.clippy]
 pedantic = "warn"
 nursery = "warn"
 unwrap_used = "warn"
diff --git a/filecaster-derive/Cargo.toml b/filecaster-derive/Cargo.toml
new file mode 100644
index 0000000..4d5f598
--- /dev/null
+++ b/filecaster-derive/Cargo.toml
@@ -0,0 +1,22 @@
+[package]
+name = "filecaster-derive"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+proc-macro = true
+
+[features]
+default = []
+merge = ["dep:merge"]
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+proc-macro-error2 = "2.0"
+syn = { version = "2.0", features = ["extra-traits", "parsing"] }
+serde.workspace = true
+merge = { workspace = true, optional = true }
+
+[dev-dependencies]
+claims.workspace = true
diff --git a/src/derive_from_file.rs b/filecaster-derive/src/from_file.rs
similarity index 93%
rename from src/derive_from_file.rs
rename to filecaster-derive/src/from_file.rs
index 1bccebb..2ba28d8 100644
--- a/src/derive_from_file.rs
+++ b/filecaster-derive/src/from_file.rs
@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
 use syn::{
@@ -78,6 +80,15 @@ fn is_from_file_struct(ty: &Type) -> bool {
     false
 }
 
+/// Extract the last identifier from a [`TypePath`].
+fn last_path_ident(ty: &Type) -> Result<String> {
+    if let Type::Path(TypePath { qself: None, path }) = ty {
+        return Ok(path.segments.last().unwrap().ident.to_string());
+    }
+
+    Err(Error::new_spanned(ty, "expected a plain struct name"))
+}
+
 /// Build the shadow field + assignment for one original field
 fn build_file_field(field: &Field) -> Result<(TokenStream, TokenStream, Option<TokenStream>)> {
     let ident = field
@@ -87,38 +98,23 @@ fn build_file_field(field: &Field) -> Result<(TokenStream, TokenStream, Option<T
     let ty = &field.ty;
 
     let field_attrs = if WITH_MERGE {
-        quote! {
-            #[merge(strategy = merge::option::overwrite_none)]
-        }
+        quote! { #[merge(strategy = merge::option::overwrite_none)] }
     } else {
         quote! {}
     };
 
-    if is_from_file_struct(ty) {
-        // Nested FromFile struct
-        let field_decl = quote! {
-            #field_attrs
-            pub #ident: Option<#ty>
-        };
-        let assign = quote! {
-            #ident: <#ty>::from_file(file.#ident)
-        };
-        return Ok((field_decl, assign, None));
-    }
-
-    // Primitive / leaf field
-    let default_expr = parse_from_file_default_attr(&field.attrs)?;
+    // Nested struct -> delegate to its own `FromFile` impl
     let field_decl = quote! {
         #field_attrs
         pub #ident: Option<#ty>
     };
-    let assign = default_expr.map_or_else(
-        || quote! { #ident: file.#ident.unwrap_or_default() },
-        |expr| quote! { #ident: file.#ident.unwrap_or_else(|| #expr) },
-    );
-    let default = quote! { #ty: Default };
+    let assign = quote! {
+            #ident: <#ty as filecaster::FromFile>::from_file(file.#ident)
+    };
 
-    Ok((field_decl, assign, Some(default)))
+    let default_bound = Some(quote! { #ty: Default });
+
+    Ok((field_decl, assign, default_bound))
 }
 
 /// Process all fields
diff --git a/src/lib.rs b/filecaster-derive/src/lib.rs
similarity index 97%
rename from src/lib.rs
rename to filecaster-derive/src/lib.rs
index 4eaab79..5a48fcb 100644
--- a/src/lib.rs
+++ b/filecaster-derive/src/lib.rs
@@ -76,10 +76,9 @@
 //!  
 //! MIT OR Apache-2.0
 
-mod derive_from_file;
 mod from_file;
 
-pub(crate) use derive_from_file::impl_from_file;
+pub(crate) use from_file::impl_from_file;
 use proc_macro::TokenStream;
 use proc_macro_error2::proc_macro_error;
 use syn::{DeriveInput, parse_macro_input};
diff --git a/filecaster/Cargo.toml b/filecaster/Cargo.toml
new file mode 100644
index 0000000..41d9f34
--- /dev/null
+++ b/filecaster/Cargo.toml
@@ -0,0 +1,29 @@
+[package]
+name = "filecaster"
+version = "0.1.0"
+edition = "2024"
+authors = ["Kristofers Solo <dev@kristofers.xyz>"]
+description = "Procedural macro to derive configuration from files, with optional merging capabilities."
+repository = "https://github.com/kristoferssolo/filecaster"
+documentation = "https://docs.rs/filecaster"
+homepage = "https://github.com/kristoferssolo/filecaster"
+license = "MIT OR Apache-2.0"
+keywords = ["proc-macro", "derive", "configuration", "file-parsing"]
+categories = ["rust-patterns", "parsing", "config"]
+exclude = ["/.github", "/.gitignore", "/tests", "*.png", "*.md"]
+readme = "README.md"
+
+[features]
+default = ["derive"]
+derive = ["dep:filecaster-derive"]
+merge = ["dep:merge", "filecaster-derive/merge"]
+
+[dependencies]
+filecaster-derive = { path = "../filecaster-derive", optional = true }
+serde.workspace = true
+merge = { workspace = true, optional = true }
+
+[dev-dependencies]
+serde_json.workspace = true
+tempfile.workspace = true
+toml.workspace = true
diff --git a/src/from_file.rs b/filecaster/src/lib.rs
similarity index 93%
rename from src/from_file.rs
rename to filecaster/src/lib.rs
index a1b479a..da91ab2 100644
--- a/src/from_file.rs
+++ b/filecaster/src/lib.rs
@@ -1,3 +1,4 @@
+pub use filecaster_derive::FromFile;
 use serde::{Deserialize, Serialize};
 
 /// Marker for types that can be built from an `Option<Shadow>` produced by the macro.
diff --git a/tests/from_file.rs b/filecaster/tests/from_file.rs
similarity index 100%
rename from tests/from_file.rs
rename to filecaster/tests/from_file.rs
diff --git a/tests/from_file_io.rs b/filecaster/tests/from_file_io.rs
similarity index 100%
rename from tests/from_file_io.rs
rename to filecaster/tests/from_file_io.rs
diff --git a/filecaster/tests/nested_structure.rs b/filecaster/tests/nested_structure.rs
new file mode 100644
index 0000000..622fdd1
--- /dev/null
+++ b/filecaster/tests/nested_structure.rs
@@ -0,0 +1,14 @@
+use filecaster::FromFile;
+
+#[derive(Debug, Default, Clone, PartialEq, FromFile)]
+pub struct Coordinates {
+    x: i32,
+    y: i32,
+}
+
+#[derive(Debug, Clone, PartialEq, FromFile)]
+pub struct Parent {
+    #[from_file(default = "Foo")]
+    name: String,
+    coordinates: Coordinates,
+}