diff --git a/jwt/builder.go b/jwt/builder.go
index fa177988..11ee09e6 100644
--- a/jwt/builder.go
+++ b/jwt/builder.go
@@ -18,6 +18,7 @@
 package jwt
 
 import (
+	"bytes"
 	"reflect"
 
 	"gopkg.in/square/go-jose.v2/json"
@@ -136,7 +137,11 @@ func normalize(i interface{}) (map[string]interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
-	if err := json.Unmarshal(raw, &m); err != nil {
+
+	d := json.NewDecoder(bytes.NewReader(raw))
+	d.UseNumber()
+
+	if err := d.Decode(&m); err != nil {
 		return nil, err
 	}
 
diff --git a/jwt/builder_test.go b/jwt/builder_test.go
index 25a656f7..8213c47f 100644
--- a/jwt/builder_test.go
+++ b/jwt/builder_test.go
@@ -24,6 +24,7 @@ import (
 	"encoding/hex"
 	"encoding/pem"
 	"errors"
+	"fmt"
 	"io"
 	"reflect"
 	"sort"
@@ -34,6 +35,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"gopkg.in/square/go-jose.v2"
+	"gopkg.in/square/go-jose.v2/json"
 )
 
 type testClaims struct {
@@ -56,6 +58,30 @@ var sampleClaims = Claims{
 	Audience: Audience{"a1", "a2"},
 }
 
+type numberClaims struct {
+	Int   int64   `json:"int"`
+	Float float64 `json:"float"`
+}
+
+func TestIntegerAndFloatsNormalize(t *testing.T) {
+	c := numberClaims{1 << 60, 12345.6789}
+
+	normalized, err := normalize(c)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ni, err := (normalized["int"].(json.Number)).Int64()
+	nf, err := (normalized["float"].(json.Number)).Float64()
+
+	if ni != c.Int {
+		t.Error(fmt.Sprintf("normalize failed to preserve int64 (got %v, wanted %v, type %s)", normalized["int"], c.Int, reflect.TypeOf(normalized["int"])))
+	}
+	if nf != c.Float {
+		t.Error(fmt.Sprintf("normalize failed to preserve float64 (got %v, wanted %v, type %s)", normalized["float"], c.Float, reflect.TypeOf(normalized["float"])))
+	}
+}
+
 func TestBuilderCustomClaimsNonPointer(t *testing.T) {
 	jwt, err := Signed(rsaSigner).Claims(testClaims{"foo"}).CompactSerialize()
 	require.NoError(t, err, "Error creating JWT.")
diff --git a/jwt/example_test.go b/jwt/example_test.go
index 17595395..fa65a025 100644
--- a/jwt/example_test.go
+++ b/jwt/example_test.go
@@ -25,6 +25,7 @@ import (
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+
 	"gopkg.in/square/go-jose.v2"
 	"gopkg.in/square/go-jose.v2/jwt"
 )
@@ -149,7 +150,7 @@ func ExampleSigned() {
 	}
 
 	fmt.Println(raw)
-	// Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOlsibGVlbGEiLCJmcnkiXSwiaXNzIjoiaXNzdWVyIiwibmJmIjoxLjQ1MTYwNjRlKzA5LCJzdWIiOiJzdWJqZWN0In0.mI6U-xUdttpOPIDUAI2uyg9lFgoqaAb-hwmz8L6L3fo
+	// Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOlsibGVlbGEiLCJmcnkiXSwiaXNzIjoiaXNzdWVyIiwibmJmIjoxNDUxNjA2NDAwLCJzdWIiOiJzdWJqZWN0In0.4PgCj0VO-uG_cb1mNA38NjJyp0N-NdGIDLoYelEkciw
 }
 
 func ExampleEncrypted() {