diff --git a/README.md b/README.md
index d103a77..ae257c9 100644
--- a/README.md
+++ b/README.md
@@ -101,20 +101,27 @@ make cli folder=path/to/folder action=build min_f=1 max_p=0.99
 The `min_f` param filters terms appearing less that it, while `max_p` filters terms appearing more than 
 in `max_p` percentage of the documents.
 
-The folder param is a path to a folder with the following structure: 
+The folder param is a path to a folder containing the documents to index. 
+The index files will be placed inside a subfolder, `.index`.
+
+Here is an example of such structure:
 ```
-├── docs
-│   ├── 1.txt
-│   ├── 2.txt
-│   └── 3.txt
-└── index
-    ├── idx.alphas
-    ├── idx.docs
-    ├── idx.offsets
-    └── idx.postings
+example
+├── .index
+│   ├── idx.alphas
+│   ├── idx.docs
+│   ├── idx.offsets
+│   └── idx.postings
+├── 1.txt
+├── 2.txt
+├── 3.txt
+└── subfolder
+    ├── 1.txt
+    ├── 2.txt
+    └── 3.txt
 ```
 
-The index folder will be created after the build command.
+The builder will walk recursively down the input folder, skipping hidden ones.
 
 **Load a document collection**
 
@@ -124,8 +131,9 @@ You can load a pre-build index by running:
 make web folder=path/to/folder
 ```
 
-You can then visit `http://0.0.0.0:3000` to find a web interface to enter free text and boolean queries.
+This will load the index inside `path/to/folder/.index`
 
+You can then visit `http://0.0.0.0:3000` to find a web interface to enter free text and boolean queries.
 
 **Query Syntax**
 
@@ -139,6 +147,4 @@ b: hello AND there OR NOT man
 ## References
 [Introduction to Information Retrieval](https://nlp.stanford.edu/IR-book/information-retrieval-book.html) - Christopher D. Manning, Prabhakar Raghavan and Hinrich Schütze
 
----
-
 *Feel free to get in touch to discuss the project!*
\ No newline at end of file
diff --git a/search/Cargo.toml b/search/Cargo.toml
index 4b0d297..d2a5798 100644
--- a/search/Cargo.toml
+++ b/search/Cargo.toml
@@ -14,3 +14,4 @@ tempdir = "0.3.7"
 regex = "1"
 argparse = "0.2.2"
 phf = { version = "0.11.2", features = ["macros"] }
+walkdir = "2.4.0"
diff --git a/search/src/disk/file_utils.rs b/search/src/disk/file_utils.rs
index 566a1d4..ff2ec27 100644
--- a/search/src/disk/file_utils.rs
+++ b/search/src/disk/file_utils.rs
@@ -2,6 +2,7 @@ use std::{
     fs::{create_dir_all, File},
     path::Path,
 };
+use walkdir::{DirEntry, WalkDir};
 
 pub fn create_and_open_file(file_path: &str) -> File {
     let path = Path::new(file_path);
@@ -9,3 +10,21 @@ pub fn create_and_open_file(file_path: &str) -> File {
 
     File::create(path).expect("error while creating file")
 }
+
+pub fn walk_dir(input_dir: &str) -> Vec<DirEntry> {
+    WalkDir::new(input_dir)
+        .sort_by_file_name()
+        .into_iter()
+        .filter_entry(|e| !is_hidden(e))
+        .filter_map(|e| e.ok())
+        .filter(|e| !e.path().is_dir())
+        .collect()
+}
+
+fn is_hidden(entry: &DirEntry) -> bool {
+    entry
+        .file_name()
+        .to_str()
+        .map(|s| s.starts_with('.'))
+        .unwrap_or(false)
+}
diff --git a/search/src/engine/builder.rs b/search/src/engine/builder.rs
index 90a1e8a..9dda0eb 100644
--- a/search/src/engine/builder.rs
+++ b/search/src/engine/builder.rs
@@ -1,3 +1,5 @@
+use crate::disk::file_utils::walk_dir;
+
 use super::{
     documents::{Document, Documents},
     postings::{Posting, Postings, PostingsList},
@@ -41,11 +43,7 @@ fn build_in_memory(
     max_freq_percentage_threshold: f64,
     min_freq_threshold: u32,
 ) -> InMemory {
-    let files: Vec<fs::DirEntry> = fs::read_dir(input_dir)
-        .expect("error while retrieving input directory content")
-        .map(std::result::Result::unwrap)
-        .collect();
-
+    let files = walk_dir(input_dir);
     // document counter
     let doc_id_mutex = Mutex::new(0);
     // postings list
@@ -65,7 +63,8 @@ fn build_in_memory(
                 .progress_chars(PROGRESS_CHARS),
         )
         .for_each(|d| {
-            let file_content = fs::read_to_string(d.path()).expect("error while reading file");
+            let file_content: String =
+                fs::read_to_string(d.path()).expect("error while reading file");
             let tokens = preprocessor.tokenize_and_stem(&file_content);
 
             let mut doc_id = doc_id_mutex.lock().unwrap();
diff --git a/search/src/main.rs b/search/src/main.rs
index 450e53a..3ed689c 100644
--- a/search/src/main.rs
+++ b/search/src/main.rs
@@ -68,8 +68,7 @@ fn main() {
     let action = &args[2];
     let build_index = action == "build";
 
-    let index_path = format!("{base_path}/index/idx");
-    let docs_path = format!("{base_path}/docs");
+    let index_path = format!("{base_path}/.index/idx");
 
     if build_index {
         let min_freq: Result<u32, _> = args[3].parse();
@@ -84,10 +83,10 @@ fn main() {
             return;
         };
 
-        println!("Start build on directory [{docs_path}]\n");
+        println!("Start build on directory [{base_path}]\n");
 
         let start_time = Instant::now();
-        Engine::build_engine(&docs_path, &index_path, max_frequency_perc, min_freq);
+        Engine::build_engine(base_path, &index_path, max_frequency_perc, min_freq);
         let elapsed_time = start_time.elapsed();
 
         println!(
diff --git a/server/src/main.rs b/server/src/main.rs
index c5efcd7..ad53c30 100644
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -40,7 +40,7 @@ async fn main() {
     }
 
     let base_path = &args[1];
-    let index_path = format!("{base_path}/index/idx");
+    let index_path = format!("{base_path}/.index/idx");
 
     let state = Arc::new(AppState {
         index_path: base_path.clone(),