diff --git a/auth/jwt/middleware.go b/auth/jwt/middleware.go
index b03b9aa..ff44ed7 100644
--- a/auth/jwt/middleware.go
+++ b/auth/jwt/middleware.go
@@ -66,13 +66,25 @@
 	}
 }
 
-type claimsFactory func() jwt.Claims
+type ClaimsFactory func() jwt.Claims
+
+// MapClaimsFactory is a ClaimsFactory that returns 
+// an empty jwt.MapClaims.
+func MapClaimsFactory() jwt.Claims {
+    return jwt.MapClaims{}
+}
+
+// StandardClaimsFactory is a ClaimsFactory that returns 
+// an empty jwt.StandardClaims.
+func StandardClaimsFactory() jwt.Claims {
+    return &jwt.StandardClaims{}
+}
 
 // NewParser creates a new JWT token parsing middleware, specifying a
 // jwt.Keyfunc interface, the signing method and the claims type to be used. NewParser
 // adds the resulting  claims to endpoint context or returns error on invalid token.
 // Particularly useful for servers.
-func NewParser(keyFunc jwt.Keyfunc, method jwt.SigningMethod, newClaims claimsFactory) endpoint.Middleware {
+func NewParser(keyFunc jwt.Keyfunc, method jwt.SigningMethod, newClaims ClaimsFactory) endpoint.Middleware {
 	return func(next endpoint.Endpoint) endpoint.Endpoint {
 		return func(ctx context.Context, request interface{}) (response interface{}, err error) {
 			// tokenString is stored in the context from the transport handlers.
diff --git a/auth/jwt/middleware_test.go b/auth/jwt/middleware_test.go
index 977bef6..3278e13 100644
--- a/auth/jwt/middleware_test.go
+++ b/auth/jwt/middleware_test.go
@@ -74,7 +74,7 @@
 		return key, nil
 	}
 
-	parser := NewParser(keys, method, func() jwt.Claims { return jwt.MapClaims{} })(e)
+	parser := NewParser(keys, method, MapClaimsFactory)(e)
 
 	// No Token is passed into the parser
 	_, err := parser(context.Background(), struct{}{})
@@ -94,7 +94,7 @@
 	}
 
 	// Invalid Method is used in the parser
-	badParser := NewParser(keys, invalidMethod, func() jwt.Claims { return jwt.MapClaims{} })(e)
+	badParser := NewParser(keys, invalidMethod, MapClaimsFactory)(e)
 	ctx = context.WithValue(context.Background(), JWTTokenContextKey, signedKey)
 	_, err = badParser(ctx, struct{}{})
 	if err == nil {
@@ -110,7 +110,7 @@
 		return []byte("bad"), nil
 	}
 
-	badParser = NewParser(invalidKeys, method, func() jwt.Claims { return jwt.MapClaims{} })(e)
+	badParser = NewParser(invalidKeys, method, MapClaimsFactory)(e)
 	ctx = context.WithValue(context.Background(), JWTTokenContextKey, signedKey)
 	_, err = badParser(ctx, struct{}{})
 	if err == nil {
@@ -134,7 +134,7 @@
 	}
 
 	// Test for malformed token error response
-	parser = NewParser(keys, method, func() jwt.Claims { return &jwt.StandardClaims{} })(e)
+	parser = NewParser(keys, method, StandardClaimsFactory)(e)
 	ctx = context.WithValue(context.Background(), JWTTokenContextKey, malformedKey)
 	ctx1, err = parser(ctx, struct{}{})
 	if want, have := ErrTokenMalformed, err; want != have {
@@ -142,7 +142,7 @@
 	}
 
 	// Test for expired token error response
-	parser = NewParser(keys, method, func() jwt.Claims { return &jwt.StandardClaims{} })(e)
+	parser = NewParser(keys, method, StandardClaimsFactory)(e)
 	expired := jwt.NewWithClaims(method, jwt.StandardClaims{ExpiresAt: time.Now().Unix() - 100})
 	token, err := expired.SignedString(key)
 	if err != nil {
@@ -155,7 +155,7 @@
 	}
 
 	// Test for not activated token error response
-	parser = NewParser(keys, method, func() jwt.Claims { return &jwt.StandardClaims{} })(e)
+	parser = NewParser(keys, method, StandardClaimsFactory)(e)
 	notactive := jwt.NewWithClaims(method, jwt.StandardClaims{NotBefore: time.Now().Unix() + 100})
 	token, err = notactive.SignedString(key)
 	if err != nil {
@@ -168,7 +168,7 @@
 	}
 
 	// test valid standard claims token
-	parser = NewParser(keys, method, func() jwt.Claims { return &jwt.StandardClaims{} })(e)
+	parser = NewParser(keys, method, StandardClaimsFactory)(e)
 	ctx = context.WithValue(context.Background(), JWTTokenContextKey, standardSignedKey)
 	ctx1, err = parser(ctx, struct{}{})
 	if err != nil {
@@ -204,7 +204,7 @@
 func TestIssue562(t *testing.T) {
 	var (
 		kf  = func(token *jwt.Token) (interface{}, error) { return []byte("secret"), nil }
-		e   = NewParser(kf, jwt.SigningMethodHS256, func() jwt.Claims { return jwt.MapClaims{} })(endpoint.Nop)
+		e   = NewParser(kf, jwt.SigningMethodHS256, MapClaimsFactory)(endpoint.Nop)
 		key = JWTTokenContextKey
 		val = "eyJhbGciOiJIUzI1NiIsImtpZCI6ImtpZCIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjoiZ28ta2l0In0.14M2VmYyApdSlV_LZ88ajjwuaLeIFplB8JpyNy0A19E"
 		ctx = context.WithValue(context.Background(), key, val)