diff --git a/.gitignore b/.gitignore
index 8881cfa..18483ef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .vscode/
 lab/
+bin/*
\ No newline at end of file
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..02a8362
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,5 @@
+client:
+	go build -o bin/client cmd/client/main.go
+
+server:
+	go build -o bin/server cmd/server/main.go
\ No newline at end of file
diff --git a/cmd/client/main.go b/cmd/client/main.go
index be04c43..feb34e6 100644
--- a/cmd/client/main.go
+++ b/cmd/client/main.go
@@ -1,44 +1,44 @@
-package main
+package client
 
 import (
 	"cosync/internal/client"
 	"cosync/internal/server"
-	"cosync/tests"
+
+	// "cosync/tests"
 	"os"
 )
 
-//TODO: handle arguments correctly
+// TODO: handle arguments correctly
 func main() {
 	argc := len(os.Args)
 	if argc < 2 {
 		panic("Not enough arguments (try --help)")
 	}
 
-
 	for i := 1; i < argc; i++ {
 
-		switch (os.Args[i]) {
-		
+		switch os.Args[i] {
+
 		case "-s":
 			server.Run()
 			// break
-		
+
 		case "-c":
 			client.Run()
 			// break
 
 		case "-p":
 			panic("Not implemented")
-		
+
 		case "--help":
 			panic("Not implemented")
 
-		case "--test":
-			tests.TestAll()
-		
+		// case "--test":
+		// 	tests.TestAll()
+
 		default:
 			panic("Bad argument : \"" + os.Args[i] + "\"")
 
+		}
 	}
-	}
-}
\ No newline at end of file
+}
diff --git a/cmd/server/main.go b/cmd/server/main.go
index f275077..54e7b99 100644
--- a/cmd/server/main.go
+++ b/cmd/server/main.go
@@ -1 +1,38 @@
-package server
\ No newline at end of file
+package server
+
+import (
+	"cosync/internal/server"
+	// "cosync/tests"
+	"os"
+)
+
+// TODO: handle arguments correctly
+func main() {
+	argc := len(os.Args)
+	if argc < 2 {
+		panic("Not enough arguments (try --help)")
+	}
+
+	for i := 1; i < argc; i++ {
+
+		switch os.Args[i] {
+
+		case "-s":
+			server.Run()
+			// break
+
+		case "-p":
+			panic("Not implemented")
+
+		case "--help":
+			panic("Not implemented")
+
+		// case "--test":
+		// 	tests.TestAll()
+
+		default:
+			panic("Bad argument : \"" + os.Args[i] + "\"")
+
+		}
+	}
+}
diff --git a/internal/core/config.go b/internal/core/config.go
index 4166fc2..617a99e 100644
--- a/internal/core/config.go
+++ b/internal/core/config.go
@@ -7,14 +7,11 @@ import (
 	"github.com/spf13/viper"
 )
 
-
 // Config will follow this model
 // server : string
 // port : int
 
-
-
-
+var config_loaded bool = false
 
 // Load config file
 func LoadConfig() error {
@@ -43,6 +40,7 @@ func LoadConfig() error {
 		// return err
 	}
 
+	config_loaded = true
 	return nil
 }
 
@@ -57,7 +55,16 @@ func LoadSyncList() error {
 }
 
 // returns all config variables
-// ! WARNING: Do not use this function without executing LoadConfig prior
 func GetConfig() map[string]any {
-	return viper.AllSettings()
+
+	if config_loaded {
+		return viper.AllSettings()
+	} else {
+		err := LoadConfig()
+		if err != nil {
+			panic("GetConfig: Failed to load config file -> " + err.Error())
+		}
+
+		return viper.AllSettings()
+	}
 }
diff --git a/internal/core/models.go b/internal/core/models.go
index 3a18d09..e0c4b3f 100644
--- a/internal/core/models.go
+++ b/internal/core/models.go
@@ -5,10 +5,10 @@ import (
 )
 
 type File struct {
-	ID       string
-	ParentDirectory     string
-	Metadata FileMetadata
-	State    SynchronizationState
+	ID              string
+	ParentDirectory Folder
+	Metadata        FileMetadata
+	State           SynchronizationState
 }
 
 type FileMetadata struct {
@@ -22,4 +22,13 @@ type SynchronizationState struct {
 	Status    string // "pending", "in_progress", "completed", "error"
 	Progress  float64
 	LastError error
+}
+
+type Folder struct {
+	ID				string
+	Files			[]File
+	Subfolders		[]Folder
+	
+	Name 			string
+	Path			string
 }
\ No newline at end of file
diff --git a/internal/core/utils.go b/internal/core/utils.go
index ebaad97..8162569 100644
--- a/internal/core/utils.go
+++ b/internal/core/utils.go
@@ -1,8 +1,36 @@
 package core
 
+import (
+	"crypto/sha256"
+	"io"
+	"os"
+)
 
-//! Not implemented
-func CompareFiles(file1 File, file2 File) bool {
-	return false
+// Panic if e contains an error
+func Check(e error) {
+	if e != nil {
+		panic("Check: A fatal error occured during execution -> " + e.Error())
+	}
 }
 
+// Returns true if files correspond
+func CompareFiles(file1 File, file2 File) bool {
+	return file1.Metadata.Hash == file2.Metadata.Hash
+}
+
+// Gets the sha256 hash of a file's content
+func GetHash(file File) ([]byte, error) {
+	// init
+	hasher := sha256.New()
+	file_path := "" //TODO: missing
+	// Open file
+	f, err := os.Open(file_path)
+	if err != nil { // Path error
+		return nil, err
+	}
+	// Compute hash
+	io.Copy(hasher, f)
+	sum := hasher.Sum(nil)
+
+	return sum, nil
+}
diff --git a/internal/server/server.go b/internal/server/server.go
index 7a5be5a..907de84 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -27,7 +27,7 @@ func Run() {
 	serverPort := strconv.Itoa(config["port"].(int))
 
 	// Listening
-	listener, err := net.Listen("tcp", ":" + serverPort)
+	listener, err := net.Listen("tcp", ":"+serverPort)
 	if err != nil {
 		panic(err)
 	}
@@ -65,7 +65,7 @@ func handleConnection(conn net.Conn) {
 			log.Println("Error reading from ", clientAddress, ": ", err)
 			return
 		}
-		
+
 		// to rm
 		println(message)
 		// fmt.Println("Received from client:", message)
@@ -76,7 +76,7 @@ func handleConnection(conn net.Conn) {
 		// Send a response to the client
 		_, err = conn.Write([]byte("Server received your message\n"))
 		if err != nil {
-			log.Println("Error replying to", clientAddress,": ", err)
+			log.Println("Error replying to", clientAddress, ": ", err)
 			return
 		}
 	}
diff --git a/tests/cosync_test.go b/tests/cosync_test.go
new file mode 100644
index 0000000..b0b4dcb
--- /dev/null
+++ b/tests/cosync_test.go
@@ -0,0 +1,22 @@
+package tests
+
+import (
+	"testing"
+	"cosync/internal/client"
+	"cosync/internal/server"
+)
+
+func TestAll(t *testing.T) {
+	TestClientServerCommunication(t)
+}
+
+func TestClientServerCommunication(t *testing.T) {
+	go client.Run()
+	go server.Run()
+}
+
+func TestConfigLoading(t *testing.T) {
+}
+
+func TestConfigCreation(t *testing.T) {
+}
\ No newline at end of file
diff --git a/tests/tests.go b/tests/tests.go
deleted file mode 100644
index df7e5a8..0000000
--- a/tests/tests.go
+++ /dev/null
@@ -1,26 +0,0 @@
-package tests
-
-import (
-	// "testing"
-	"cosync/internal/client"
-	"cosync/internal/server"
-)
-
-func TestAll() bool {
-	TestClientServerCommunication()
-	return false
-}
-
-func TestClientServerCommunication() bool {
-	go client.Run()
-	go server.Run()
-	return false
-}
-
-func TestConfigLoading() bool {
-	return false
-}
-
-func TestConfigCreation() bool {
-	return false
-}
\ No newline at end of file