diff --git a/internal/jwt/service.go b/internal/jwt/service.go
index 6a6f80b..9c74f9e 100644
--- a/internal/jwt/service.go
+++ b/internal/jwt/service.go
@@ -1,6 +1,7 @@
 package jwt
 
 import (
+	"maps"
 	"time"
 
 	"github.com/golang-jwt/jwt/v5"
@@ -9,41 +10,38 @@ import (
 
 type Service struct {
 	signer Signer
-	expiry time.Duration
 }
 
-func NewService(signer Signer, exp time.Duration) *Service {
+func NewService(signer Signer) *Service {
 	return &Service{
 		signer: signer,
-		expiry: exp,
 	}
 }
 
 // Generate creates a new JWT token for a given user ID and
 // returns the token string along with its JTI(JWT IDentifier).
-func (s *Service) Generate(userID int) (string, string, error) {
+func (s *Service) Generate(ttl time.Duration, extraClaims jwt.MapClaims) (string, string, error) {
 	jti := uuid.NewString()
 
 	claims := jwt.MapClaims{
-		"sub": userID,
 		"jti": jti,
-		"exp": time.Now().Add(s.expiry).Unix(),
+		"exp": time.Now().Add(ttl).Unix(),
 		"iat": time.Now().Unix(),
 	}
+	maps.Copy(claims, extraClaims)
 
 	token, err := s.signer.Sign(claims)
 	return token, jti, err
 }
 
-// Validate verifies the JWT token and extracts the user ID and JTI(JWT IDentifier).
-func (s *Service) Validate(token string) (int, string, error) {
+// Validate verifies the JWT token and extracts the claims and JTI(JWT IDentifier).
+func (s *Service) Validate(token string) (jwt.MapClaims, string, error) {
 	claims, err := s.signer.Verify(token)
 	if err != nil {
-		return 0, "", err
+		return nil, "", err
 	}
 
-	sub := int(claims.(jwt.MapClaims)["sub"].(float64))
 	jti := claims.(jwt.MapClaims)["jti"].(string)
 
-	return sub, jti, nil
+	return claims.(jwt.MapClaims), jti, nil
 }