diff --git a/readme.md b/readme.md
index 911471e..580a2fe 100644
--- a/readme.md
+++ b/readme.md
@@ -4,21 +4,31 @@ A simple, self-contained module for making and verifying JWTs using HMAC SHA256.
 ## Example
 ```v
 import jwt
-import json
 
-const secret := "secret-key"
+const secret = 'secret-key'
 
-// Create a new token
-payload := jwt.Payload{
-    sub: "1234567890",
-    ext: json.encode(/* some struct */)
+pub struct Credential {
+	user string
+	pass string
 }
-token := jwt.Token.new(payload, secret)
-respond_with(token.str())
 
-// Validate a token from the web
-token := jwt.Token.from_str(/* receive a token from the web */)
-if token.valid(secret) {
-    // do stuff
+fn main() {
+	// Create a new token
+	payload := jwt.Payload[Credential]{
+		sub: '1234567890'
+		ext: Credential{
+			user: 'splashsky'
+			pass: 'password'
+		}
+	}
+	token := jwt.Token.new(payload, secret)
+	receive_token_from_web := token.str()
+
+	// Validate a token from the web
+	obj_token := jwt.from_str[Credential](receive_token_from_web)!
+	if obj_token.valid(secret) {
+		println('token valid!')
+		dump(obj_token.payload.ext)
+	}
 }
 ```
diff --git a/src/header.v b/src/header.v
index 989bc85..1baf899 100644
--- a/src/header.v
+++ b/src/header.v
@@ -1,6 +1,6 @@
 module jwt
 
 pub struct Header {
-	alg string = "HS256"
-	typ string = "JWT"
+	alg string = 'HS256'
+	typ string = 'JWT'
 }
diff --git a/src/jwt.v b/src/jwt.v
index cc7b675..564ab5b 100644
--- a/src/jwt.v
+++ b/src/jwt.v
@@ -1,75 +1,66 @@
 module jwt
 
 import encoding.base64
-import x.json2 as json
+import json
 import crypto.hmac
 import crypto.sha256
 import time
 
-pub struct Token {
-	header string
-	payload string
+pub struct Token[T] {
+	header    string
 	signature string
+pub:
+	payload Payload[T]
 }
 
-pub fn Token.new(payload Payload, secret string) Token {
-	header := base64.url_encode(json.encode[Header](Header{}).bytes())
-	payload_string := base64.url_encode(json.encode[Payload](payload).bytes())
-	signature := base64.url_encode(hmac.new(
-		secret.bytes(),
-		"${header}.${payload_string}".bytes(),
-		sha256.sum,
-		sha256.block_size
-	).bytestr().bytes())
+pub fn Token.new[T](payload Payload[T], secret string) Token[T] {
+	header := base64.url_encode(json.encode(Header{}).bytes())
+	payload_string := base64.url_encode(json.encode(payload).bytes())
 
-	return Token{
-		header: header,
-		payload: payload_string,
-		signature: signature,
+	signature := base64.url_encode(hmac.new(secret.bytes(), '${header}.${payload_string}'.bytes(),
+		sha256.sum, sha256.block_size).bytestr().bytes())
+
+	return Token[T]{
+		header: header
+		payload: payload
+		signature: signature
 	}
 }
 
-pub fn Token.from_str(token string) !Token {
-	parts := token.split(".")
+pub fn from_str[T](token string) !Token[T] {
+	parts := token.split('.')
 	if parts.len != 3 {
-		return error("Invalid token")
+		return error('Invalid token')
 	}
 
-	return Token{
-		header: parts[0],
-		payload: parts[1],
-		signature: parts[2],
+	return Token[T]{
+		header: parts[0]
+		payload: json.decode(Payload[T], base64.url_decode_str(parts[1]))!
+		signature: parts[2]
 	}
 }
 
-pub fn (t Token) str() string {
-	return t.header + "." + t.payload + "." + t.signature
+pub fn (t Token[T]) str() string {
+	payload := base64.url_encode(json.encode(t.payload).bytes())
+	return t.header + '.' + payload + '.' + t.signature
 }
 
-pub fn (t Token) valid(secret string) bool {
+pub fn (t Token[T]) valid(secret string) bool {
 	if t.expired() {
 		return false
 	}
 
-	parts := t.str().split(".")
+	parts := t.str().split('.')
 	if parts.len != 3 {
 		return false
 	}
 
-	expected_signature := base64.url_encode(hmac.new(
-		secret.bytes(),
-		"${parts[0]}.${parts[1]}".bytes(), // header + payload
-		sha256.sum,
-		sha256.block_size
-	).bytestr().bytes())
+	expected_signature := base64.url_encode(hmac.new(secret.bytes(), '${parts[0]}.${parts[1]}'.bytes(), // header + payload
+	 sha256.sum, sha256.block_size).bytestr().bytes())
 
 	return parts[2] == expected_signature // signature == expected_signature
 }
 
-pub fn (t Token) payload() !Payload {
-	return json.decode[Payload](base64.url_decode_str(t.payload))!
-}
-
-pub fn (t Token) expired() bool {
-	return t.payload() or { return false }.exp or { return false } < time.now()
+pub fn (t Token[T]) expired() bool {
+	return t.payload.exp.time() or { return false } < time.now()
 }
diff --git a/src/jwt_test.v b/src/jwt_test.v
index 2656297..952d7c0 100644
--- a/src/jwt_test.v
+++ b/src/jwt_test.v
@@ -1,46 +1,71 @@
 module jwt
 
-import x.json2 as json
 import time
 
-const secret := "secret"
-const claims := {"name": "John Doe", "admin": "true"}
+const no_secret = 'pass secret'
+const secret = 'secret'
+const claims = {
+	'name':  'John Doe'
+	'admin': 'true'
+}
 
 fn test_valid() {
-	payload := Payload{
-		sub: "1234567890",
-		ext: json.encode(claims)
+	payload := Payload[map[string]string]{
+		sub: '1234567890'
+		ext: jwt.claims
+	}
+	token := Token.new(payload, jwt.secret)
+
+	assert token.valid(jwt.secret)
+}
+
+fn test_invalid() {
+	payload := Payload[map[string]string]{
+		sub: '1234567890'
+		ext: jwt.claims
 	}
-	token := Token.new(payload, secret)
+	token := Token.new(payload, jwt.secret)
 
-	assert token.valid(secret) == true
+	assert !token.valid(jwt.no_secret)
 }
 
 fn test_expired() {
-	payload := Payload{
-		sub: "1234567890",
-		ext: json.encode(claims),
-		exp: time.parse("2019-01-01 00:00:00") or { panic(err) }
+	payload := Payload[map[string]string]{
+		sub: '1234567890'
+		ext: jwt.claims
+		exp: '2019-01-01 00:00:00'
+	}
+	token := Token.new(payload, jwt.secret)
+
+	assert !token.valid(jwt.secret)
+	assert token.expired()
+}
+
+fn test_no_expired() {
+	payload := Payload[map[string]string]{
+		sub: '1234567890'
+		ext: jwt.claims
+		exp: time.now().add_seconds(10).str()
 	}
-	token := Token.new(payload, secret)
+	token := Token.new(payload, jwt.secret)
 
-	assert token.expired() == true
-	assert token.valid(secret) == false
+	assert token.valid(jwt.secret)
+	assert !token.expired()
 }
 
 fn test_from_str() {
-	payload := Payload{
-		sub: "1234567890",
-		ext: json.encode(claims)
+	payload := Payload[map[string]string]{
+		sub: '1234567890'
+		ext: jwt.claims
 	}
-	payload2 := Payload{
-		sub: "0987654321",
-		ext: json.encode(claims)
+	payload2 := Payload[map[string]string]{
+		sub: '0987654321'
+		ext: jwt.claims
 	}
 
-	token := Token.new(payload, secret)
-	token2 := Token.from_str(token.str())!
-	token3 := Token.new(payload2, secret)
+	token := Token.new(payload, jwt.secret)
+	token2 := from_str[map[string]string](token.str())! //Não está funcionando
+	token3 := Token.new(payload2, jwt.secret)
 
 	assert token2 == token
 	assert token2 != token3
diff --git a/src/payload.v b/src/payload.v
index 8d7f146..512a07f 100644
--- a/src/payload.v
+++ b/src/payload.v
@@ -2,11 +2,18 @@ module jwt
 
 import time
 
-pub struct Payload {
+type JsTime = string
+
+pub struct Payload[T] {
+pub:
 	iss ?string @[omitempty]
 	sub ?string @[omitempty]
 	aud ?string @[omitempty]
-	exp ?time.Time @[omitempty]
-	iat ?time.Time @[omitempty]
-	ext ?string @[omitempty]
+	exp JsTime  @[omitempty]
+	iat JsTime  @[omitempty]
+	ext T       @[omitempty]
+}
+
+pub fn (jst JsTime) time() ?time.Time {
+	return time.parse(jst) or { return none }
 }