diff --git a/go.mod b/go.mod
index d341181..b432f5c 100644
--- a/go.mod
+++ b/go.mod
@@ -3,13 +3,13 @@ module github.com/dhao2001/mygo
 go 1.26.2
 
 require (
-	github.com/go-viper/mapstructure/v2 v2.4.0
 	github.com/spf13/cobra v1.10.2
 	github.com/spf13/viper v1.21.0
 )
 
 require (
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/sagikazarmark/locafero v0.11.0 // indirect
diff --git a/internal/config/config.go b/internal/config/config.go
index 0614348..e4e820f 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -34,9 +34,19 @@ type LocalStorageConfig struct {
 }
 
 type JWTConfig struct {
-	Secret     string        `mapstructure:"secret"`
-	AccessTTL  time.Duration `mapstructure:"access_ttl"`
-	RefreshTTL time.Duration `mapstructure:"refresh_ttl"`
+	Secret     string `mapstructure:"secret"`
+	AccessTTL  string `mapstructure:"access_ttl"`
+	RefreshTTL string `mapstructure:"refresh_ttl"`
+}
+
+func (j JWTConfig) AccessDuration() time.Duration {
+	d, _ := time.ParseDuration(j.AccessTTL)
+	return d
+}
+
+func (j JWTConfig) RefreshDuration() time.Duration {
+	d, _ := time.ParseDuration(j.RefreshTTL)
+	return d
 }
 
 func (c *Config) Validate() error {
@@ -62,12 +72,12 @@ func (c *Config) Validate() error {
 		errs = append(errs, errors.New("jwt.secret: must not be empty"))
 	}
 
-	if c.JWT.AccessTTL <= 0 {
-		errs = append(errs, fmt.Errorf("jwt.access_ttl: %v must be positive", c.JWT.AccessTTL))
+	if _, err := time.ParseDuration(c.JWT.AccessTTL); err != nil {
+		errs = append(errs, fmt.Errorf("jwt.access_ttl: %w", err))
 	}
 
-	if c.JWT.RefreshTTL <= 0 {
-		errs = append(errs, fmt.Errorf("jwt.refresh_ttl: %v must be positive", c.JWT.RefreshTTL))
+	if _, err := time.ParseDuration(c.JWT.RefreshTTL); err != nil {
+		errs = append(errs, fmt.Errorf("jwt.refresh_ttl: %w", err))
 	}
 
 	return errors.Join(errs...)
diff --git a/internal/config/load.go b/internal/config/load.go
index d306023..03ee4a4 100644
--- a/internal/config/load.go
+++ b/internal/config/load.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/go-viper/mapstructure/v2"
 	"github.com/spf13/viper"
 )
 
@@ -24,10 +23,6 @@ func defaults(v *viper.Viper) {
 	v.SetDefault("jwt.refresh_ttl", "168h")
 }
 
-func decodeHook() viper.DecoderConfigOption {
-	return viper.DecodeHook(mapstructure.StringToTimeDurationHookFunc())
-}
-
 func New() *viper.Viper {
 	v := viper.New()
 	v.SetEnvPrefix("MYGO")
@@ -54,7 +49,7 @@ func Load(v *viper.Viper, cfgFile string) (*Config, error) {
 	}
 
 	var cfg Config
-	if err := v.Unmarshal(&cfg, decodeHook()); err != nil {
+	if err := v.Unmarshal(&cfg); err != nil {
 		return nil, fmt.Errorf("unmarshal config: %w", err)
 	}
 
diff --git a/internal/config/load_test.go b/internal/config/load_test.go
index dd3fc7d..12b19cb 100644
--- a/internal/config/load_test.go
+++ b/internal/config/load_test.go
@@ -25,8 +25,8 @@ func TestDefaults(t *testing.T) {
 		{"database.path", cfg.Database.Path, "data/mygo.db"},
 		{"storage.driver", cfg.Storage.Driver, "local"},
 		{"storage.local.path", cfg.Storage.Local.Path, "data/files"},
-		{"jwt.access_ttl", cfg.JWT.AccessTTL, 15 * time.Minute},
-		{"jwt.refresh_ttl", cfg.JWT.RefreshTTL, 168 * time.Hour},
+		{"jwt.access_ttl", cfg.JWT.AccessTTL, "15m"},
+		{"jwt.refresh_ttl", cfg.JWT.RefreshTTL, "168h"},
 	}
 
 	for _, tt := range tests {
@@ -86,11 +86,11 @@ jwt:
 	if cfg.JWT.Secret != "test-secret" {
 		t.Errorf("jwt.secret = %q, want %q", cfg.JWT.Secret, "test-secret")
 	}
-	if cfg.JWT.AccessTTL != 30*time.Minute {
-		t.Errorf("jwt.access_ttl = %v, want %v", cfg.JWT.AccessTTL, 30*time.Minute)
+	if cfg.JWT.AccessTTL != "30m" {
+		t.Errorf("jwt.access_ttl = %q, want %q", cfg.JWT.AccessTTL, "30m")
 	}
-	if cfg.JWT.RefreshTTL != 72*time.Hour {
-		t.Errorf("jwt.refresh_ttl = %v, want %v", cfg.JWT.RefreshTTL, 72*time.Hour)
+	if cfg.JWT.RefreshTTL != "72h" {
+		t.Errorf("jwt.refresh_ttl = %q, want %q", cfg.JWT.RefreshTTL, "72h")
 	}
 }
 
@@ -195,3 +195,17 @@ func TestExplicitConfigFileNotFound(t *testing.T) {
 		t.Fatal("expected error when explicitly specifying a nonexistent config file")
 	}
 }
+
+func TestJWTConfigAccessDuration(t *testing.T) {
+	j := JWTConfig{AccessTTL: "15m"}
+	if got := j.AccessDuration(); got != 15*time.Minute {
+		t.Errorf("AccessDuration() = %v, want %v", got, 15*time.Minute)
+	}
+}
+
+func TestJWTConfigRefreshDuration(t *testing.T) {
+	j := JWTConfig{RefreshTTL: "168h"}
+	if got := j.RefreshDuration(); got != 168*time.Hour {
+		t.Errorf("RefreshDuration() = %v, want %v", got, 168*time.Hour)
+	}
+}