diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/AuthenticationController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/AuthenticationController.java
index cc9ed2e..5fd000b 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/AuthenticationController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/AuthenticationController.java
@@ -4,6 +4,7 @@ import ch.usi.inf.sa4.sanmarinoes.smarthut.config.JWTTokenUtil;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.JWTRequest;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.JWTResponse;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.UserUpdateRequest;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.error.UserNotFoundException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
 import io.swagger.annotations.Authorization;
 import java.security.Principal;
@@ -35,8 +36,7 @@ public class AuthenticationController {
             AuthenticationManager authenticationManager,
             UserRepository userRepository,
             JWTTokenUtil jwtTokenUtil,
-            JWTUserDetailsService userDetailsService,
-            UserRepository users) {
+            JWTUserDetailsService userDetailsService) {
         this.authenticationManager = authenticationManager;
         this.userRepository = userRepository;
         this.jwtTokenUtil = jwtTokenUtil;
@@ -45,9 +45,25 @@ public class AuthenticationController {
 
     @PostMapping("/login")
     public JWTResponse login(@RequestBody JWTRequest authenticationRequest) throws Exception {
-        authenticate(authenticationRequest.getUsername(), authenticationRequest.getPassword());
+        if (authenticationRequest.getUsernameOrEmail().contains("@")) {
+            // usernameOrEmail contains an email, so fetch the corresponding username
+            final User user =
+                    userRepository.findByEmailIgnoreCase(
+                            authenticationRequest.getUsernameOrEmail());
+            if (user == null) {
+                throw new UserNotFoundException();
+            }
+
+            authenticate(user.getUsername(), authenticationRequest.getPassword());
+        } else {
+            // usernameOrEmail contains a username, authenticate with that then
+            authenticate(
+                    authenticationRequest.getUsernameOrEmail(),
+                    authenticationRequest.getPassword());
+        }
+
         final UserDetails userDetails =
-                userDetailsService.loadUserByUsername(authenticationRequest.getUsername());
+                userDetailsService.loadUserByUsername(authenticationRequest.getUsernameOrEmail());
         final String token = jwtTokenUtil.generateToken(userDetails);
         return new JWTResponse(token);
     }
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/JWTRequest.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/JWTRequest.java
index d750a50..a032c05 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/JWTRequest.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/JWTRequest.java
@@ -1,15 +1,15 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.dto;
 
 public class JWTRequest {
-    private String username;
+    private String usernameOrEmail;
     private String password;
 
-    public String getUsername() {
-        return this.username;
+    public String getUsernameOrEmail() {
+        return this.usernameOrEmail;
     }
 
-    public void setUsername(String username) {
-        this.username = username;
+    public void setUsernameOrEmail(String usernameOrEmail) {
+        this.usernameOrEmail = usernameOrEmail;
     }
 
     public String getPassword() {
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/UserRegistrationRequest.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/UserRegistrationRequest.java
index b41720a..785d408 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/UserRegistrationRequest.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/UserRegistrationRequest.java
@@ -12,6 +12,9 @@ public class UserRegistrationRequest {
     /** The full name of the user */
     @NotNull
     @NotEmpty(message = "Please provide a username")
+    @Pattern(
+            regexp = "[A-Za-z0-9_\\-]+",
+            message = "Username can contain only letters, numbers, '_' and '-'")
     private String username;
 
     /** A properly salted way to store the password */
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/error/UserNotFoundException.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/error/UserNotFoundException.java
new file mode 100644
index 0000000..d2e93f6
--- /dev/null
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/error/UserNotFoundException.java
@@ -0,0 +1,11 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.error;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(code = HttpStatus.BAD_REQUEST)
+public class UserNotFoundException extends Exception {
+    public UserNotFoundException() {
+        super("No user found with given email");
+    }
+}
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/User.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/User.java
index 67f95d4..ba86712 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/User.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/User.java
@@ -2,11 +2,6 @@ package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
 
 import io.swagger.annotations.ApiModelProperty;
 import javax.persistence.*;
-import javax.validation.constraints.Email;
-import javax.validation.constraints.NotEmpty;
-import javax.validation.constraints.NotNull;
-import javax.validation.constraints.Pattern;
-import javax.validation.constraints.Size;
 
 /** A user of the Smarthut application */
 @Entity(name = "smarthutuser")
@@ -19,25 +14,15 @@ public class User {
     private Long id;
 
     /** The full name of the user */
-    @NotNull
     @Column(nullable = false)
-    @NotEmpty(message = "Please provide a full name")
     private String name;
 
     /** The full name of the user */
-    @NotNull
     @Column(nullable = false)
-    @NotEmpty(message = "Please provide a username")
     private String username;
 
     /** A properly salted way to store the password */
-    @NotNull
     @Column(nullable = false)
-    @NotEmpty(message = "Please provide a password")
-    @Size(
-            min = 6,
-            max = 255,
-            message = "Your password should be at least 6 characters long and up to 255 chars long")
     private String password;
 
     /**
@@ -45,10 +30,6 @@ public class User {
      * </code>, technically not RFC 5322 compliant
      */
     @Column(nullable = false, unique = true)
-    @NotNull
-    @NotEmpty(message = "Please provide an email")
-    @Email(message = "Please provide a valid email address")
-    @Pattern(regexp = ".+@.+\\..+", message = "Please provide a valid email address")
     private String email;
 
     @Column(nullable = false)