diff --git a/example_test.go b/example_test.go
index fa8bc34..7cfd377 100644
--- a/example_test.go
+++ b/example_test.go
@@ -10,7 +10,7 @@ import (
 
 func ExampleNegotiator_Accept() {
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
-	req.Header.Set(negotiator.HeaderAccept, "text/html, application/*;q=0.9, image/jpeg;q=0.8")
+	req.Header.Set("Accept", "text/html, application/*;q=0.9, image/jpeg;q=0.8")
 	negotiator := negotiator.New(req)
 
 	fmt.Println(negotiator.Accept([]string{"text/html", "application/json", "image/jpeg"}))
@@ -25,7 +25,7 @@ func ExampleNegotiator_Accept() {
 
 func ExampleNegotiator_Encoding() {
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
-	req.Header.Set(negotiator.HeaderAcceptEncoding, "gzip, compress;q=0.2, identity;q=0.5")
+	req.Header.Set("Accept-Encoding", "gzip, compress;q=0.2, identity;q=0.5")
 	negotiator := negotiator.New(req)
 
 	fmt.Println(negotiator.Encoding([]string{"identity", "gzip"}))
@@ -37,7 +37,7 @@ func ExampleNegotiator_Encoding() {
 
 func ExampleNegotiator_Language() {
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
-	req.Header.Set(negotiator.HeaderAcceptLanguage, "en;q=0.8, es, pt")
+	req.Header.Set("Accept-Language", "en;q=0.8, es, pt")
 	negotiator := negotiator.New(req)
 
 	fmt.Println(negotiator.Language([]string{"en", "es", "fr"}))
@@ -49,7 +49,7 @@ func ExampleNegotiator_Language() {
 
 func ExampleNegotiator_Charset() {
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
-	req.Header.Set(negotiator.HeaderAcceptCharset, "utf-8, iso-8859-1;q=0.8, utf-7;q=0.2")
+	req.Header.Set("Accept-Language", "utf-8, iso-8859-1;q=0.8, utf-7;q=0.2")
 	negotiator := negotiator.New(req)
 
 	fmt.Println(negotiator.Charset([]string{"UTF-8", "ISO-8859-1", "ISO-8859-5"}))
diff --git a/negotiator.go b/negotiator.go
index 6ec2669..c711264 100644
--- a/negotiator.go
+++ b/negotiator.go
@@ -3,19 +3,13 @@ package negotiator
 import (
 	"net/http"
 	"strings"
-)
 
-const (
-	// HeaderAccept is the HTTP "Accept" Header.
-	HeaderAccept = "Accept"
-	// HeaderAcceptLanguage is the HTTP "Accept-Language" Header.
-	HeaderAcceptLanguage = "Accept-Language"
-	// HeaderAcceptEncoding is the HTTP "Accept-Encoding" Header.
-	HeaderAcceptEncoding = "Accept-Encoding"
-	// HeaderAcceptCharset is the HTTP "Accept-Charset" Header.
-	HeaderAcceptCharset = "Accept-Charset"
+	"github.com/go-http-utils/headers"
 )
 
+// Version is this package's version
+const Version = "0.1.0"
+
 type spec struct {
 	val string
 	q   float64
@@ -82,7 +76,7 @@ func New(req *http.Request) Negotiator {
 func (n Negotiator) Accept(offers []string) (bestOffer string, matched bool) {
 	parser := newHeaderParser(n.req.Header, true)
 
-	return parser.selectOffer(offers, parser.parse(HeaderAccept))
+	return parser.selectOffer(offers, parser.parse(headers.Accept))
 }
 
 // Language returns the most preferred language from the HTTP Accept-Language
@@ -90,7 +84,7 @@ func (n Negotiator) Accept(offers []string) (bestOffer string, matched bool) {
 func (n Negotiator) Language(offers []string) (bestOffer string, matched bool) {
 	parser := newHeaderParser(n.req.Header, false)
 
-	return parser.selectOffer(offers, parser.parse(HeaderAcceptLanguage))
+	return parser.selectOffer(offers, parser.parse(headers.AcceptLanguage))
 }
 
 // Encoding returns the most preferred language from the HTTP Accept-Encoding
@@ -98,7 +92,7 @@ func (n Negotiator) Language(offers []string) (bestOffer string, matched bool) {
 func (n Negotiator) Encoding(offers []string) (bestOffer string, matched bool) {
 	parser := newHeaderParser(n.req.Header, false)
 
-	return parser.selectOffer(offers, parser.parse(HeaderAcceptEncoding))
+	return parser.selectOffer(offers, parser.parse(headers.AcceptEncoding))
 }
 
 // Charset returns the most preferred language from the HTTP Accept-Charset
@@ -106,5 +100,5 @@ func (n Negotiator) Encoding(offers []string) (bestOffer string, matched bool) {
 func (n Negotiator) Charset(offers []string) (bestOffer string, matched bool) {
 	parser := newHeaderParser(n.req.Header, false)
 
-	return parser.selectOffer(offers, parser.parse(HeaderAcceptCharset))
+	return parser.selectOffer(offers, parser.parse(headers.AcceptCharset))
 }
diff --git a/negotiator_test.go b/negotiator_test.go
index f388c3b..1a88df8 100644
--- a/negotiator_test.go
+++ b/negotiator_test.go
@@ -5,6 +5,7 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"github.com/go-http-utils/headers"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 )
@@ -27,7 +28,7 @@ type AcceptSuite struct {
 }
 
 func (s AcceptSuite) TestEmpty() {
-	n := setUpNegotiator(HeaderAccept, "application/json;q=0.2, text/html")
+	n := setUpNegotiator(headers.Accept, "application/json;q=0.2, text/html")
 
 	_, matched := n.Accept([]string{})
 
@@ -35,7 +36,7 @@ func (s AcceptSuite) TestEmpty() {
 }
 
 func (s AcceptSuite) TestCaseInsensitive() {
-	n := setUpNegotiator(HeaderAccept, "text/html")
+	n := setUpNegotiator(headers.Accept, "text/html")
 
 	bestOffer, matched := n.Accept([]string{"TEXT/HTML"})
 
@@ -44,7 +45,7 @@ func (s AcceptSuite) TestCaseInsensitive() {
 }
 
 func (s AcceptSuite) TestUnMatched() {
-	n := setUpNegotiator(HeaderAccept, "application/json;q=0.2, text/html")
+	n := setUpNegotiator(headers.Accept, "application/json;q=0.2, text/html")
 
 	_, matched := n.Accept([]string{"text/plain"})
 
@@ -52,7 +53,7 @@ func (s AcceptSuite) TestUnMatched() {
 }
 
 func (s AcceptSuite) TestEmptyAccepts() {
-	n := setUpNegotiator(HeaderAccept, "application/json;q=0")
+	n := setUpNegotiator(headers.Accept, "application/json;q=0")
 
 	_, matched := n.Accept([]string{"application/json"})
 
@@ -60,7 +61,7 @@ func (s AcceptSuite) TestEmptyAccepts() {
 }
 
 func (s AcceptSuite) TestOneMatch() {
-	n := setUpNegotiator(HeaderAccept, "application/json;q=0.2")
+	n := setUpNegotiator(headers.Accept, "application/json;q=0.2")
 
 	bestOffer, matched := n.Accept([]string{"application/json"})
 
@@ -69,7 +70,7 @@ func (s AcceptSuite) TestOneMatch() {
 }
 
 func (s AcceptSuite) TestWithAsterisk() {
-	n := setUpNegotiator(HeaderAccept, "text/*")
+	n := setUpNegotiator(headers.Accept, "text/*")
 
 	bestOffer, matched := n.Accept([]string{"text/*"})
 
@@ -78,7 +79,7 @@ func (s AcceptSuite) TestWithAsterisk() {
 }
 
 func (s AcceptSuite) TestMatchAsterisk() {
-	n := setUpNegotiator(HeaderAccept, "text/*")
+	n := setUpNegotiator(headers.Accept, "text/*")
 
 	bestOffer, matched := n.Accept([]string{"text/html"})
 
@@ -87,7 +88,7 @@ func (s AcceptSuite) TestMatchAsterisk() {
 }
 
 func (s AcceptSuite) TestFirstMatchAsterisk() {
-	n := setUpNegotiator(HeaderAccept, "text/*")
+	n := setUpNegotiator(headers.Accept, "text/*")
 
 	bestOffer, matched := n.Accept([]string{"text/html", "text/plain", "application/json"})
 
@@ -96,7 +97,7 @@ func (s AcceptSuite) TestFirstMatchAsterisk() {
 }
 
 func (s AcceptSuite) TestFirstMatchAllAsterisk() {
-	n := setUpNegotiator(HeaderAccept, "*/*, application/json;q=0.2")
+	n := setUpNegotiator(headers.Accept, "*/*, application/json;q=0.2")
 
 	bestOffer, matched := n.Accept([]string{"text/html", "application/json", "text/plain"})
 
@@ -105,7 +106,7 @@ func (s AcceptSuite) TestFirstMatchAllAsterisk() {
 }
 
 func (s AcceptSuite) TestWithAllAsterisk() {
-	n := setUpNegotiator(HeaderAccept, "*/*")
+	n := setUpNegotiator(headers.Accept, "*/*")
 
 	bestOffer, matched := n.Accept([]string{"application/json", "text/html", "text/plain"})
 
@@ -123,7 +124,7 @@ type LanguageSuite struct {
 }
 
 func (s LanguageSuite) TestEmpty() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "")
+	n := setUpNegotiator(headers.AcceptLanguage, "")
 
 	_, matched := n.Language([]string{})
 
@@ -131,7 +132,7 @@ func (s LanguageSuite) TestEmpty() {
 }
 
 func (s LanguageSuite) TestCaseInsensitive() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "En")
+	n := setUpNegotiator(headers.AcceptLanguage, "En")
 
 	bestOffer, matched := n.Language([]string{"eN"})
 
@@ -140,7 +141,7 @@ func (s LanguageSuite) TestCaseInsensitive() {
 }
 
 func (s LanguageSuite) TestUnMatched() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "en,zh")
+	n := setUpNegotiator(headers.AcceptLanguage, "en,zh")
 
 	_, matched := n.Language([]string{"ko"})
 
@@ -148,7 +149,7 @@ func (s LanguageSuite) TestUnMatched() {
 }
 
 func (s LanguageSuite) TestEmptyLanguages() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "en;q=0")
+	n := setUpNegotiator(headers.AcceptLanguage, "en;q=0")
 
 	_, matched := n.Language([]string{"en"})
 
@@ -156,7 +157,7 @@ func (s LanguageSuite) TestEmptyLanguages() {
 }
 
 func (s LanguageSuite) TestOneMatch() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "en;q=0.2")
+	n := setUpNegotiator(headers.AcceptLanguage, "en;q=0.2")
 
 	bestOffer, matched := n.Language([]string{"en"})
 
@@ -165,7 +166,7 @@ func (s LanguageSuite) TestOneMatch() {
 }
 
 func (s LanguageSuite) TestMatchAsterisk() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "*")
+	n := setUpNegotiator(headers.AcceptLanguage, "*")
 
 	bestOffer, matched := n.Language([]string{"ko", "en"})
 
@@ -174,7 +175,7 @@ func (s LanguageSuite) TestMatchAsterisk() {
 }
 
 func (s LanguageSuite) TestFirstMatchAllAsterisk() {
-	n := setUpNegotiator(HeaderAcceptLanguage, "*, ko;q=0.5")
+	n := setUpNegotiator(headers.AcceptLanguage, "*, ko;q=0.5")
 
 	bestOffer, matched := n.Language([]string{"en", "ko", "zh"})
 
@@ -192,7 +193,7 @@ type EncodingSuite struct {
 }
 
 func (s EncodingSuite) TestEmpty() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "")
+	n := setUpNegotiator(headers.AcceptEncoding, "")
 
 	_, matched := n.Encoding([]string{})
 
@@ -200,7 +201,7 @@ func (s EncodingSuite) TestEmpty() {
 }
 
 func (s EncodingSuite) TestCaseInsensitive() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "GZip")
+	n := setUpNegotiator(headers.AcceptEncoding, "GZip")
 
 	bestOffer, matched := n.Encoding([]string{"Gzip"})
 
@@ -209,7 +210,7 @@ func (s EncodingSuite) TestCaseInsensitive() {
 }
 
 func (s EncodingSuite) TestUnMatched() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "gzip,default")
+	n := setUpNegotiator(headers.AcceptEncoding, "gzip,default")
 
 	_, matched := n.Encoding([]string{"zlib"})
 
@@ -217,7 +218,7 @@ func (s EncodingSuite) TestUnMatched() {
 }
 
 func (s EncodingSuite) TestEmptyLanguages() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "gzip;q=0")
+	n := setUpNegotiator(headers.AcceptEncoding, "gzip;q=0")
 
 	_, matched := n.Encoding([]string{"gzip"})
 
@@ -225,7 +226,7 @@ func (s EncodingSuite) TestEmptyLanguages() {
 }
 
 func (s EncodingSuite) TestOneMatch() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "gzip;q=0.2")
+	n := setUpNegotiator(headers.AcceptEncoding, "gzip;q=0.2")
 
 	bestOffer, matched := n.Encoding([]string{"gzip"})
 
@@ -234,7 +235,7 @@ func (s EncodingSuite) TestOneMatch() {
 }
 
 func (s EncodingSuite) TestMatchAsterisk() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "*")
+	n := setUpNegotiator(headers.AcceptEncoding, "*")
 
 	bestOffer, matched := n.Encoding([]string{"gzip", "deflate"})
 
@@ -243,7 +244,7 @@ func (s EncodingSuite) TestMatchAsterisk() {
 }
 
 func (s EncodingSuite) TestFirstMatchAllAsterisk() {
-	n := setUpNegotiator(HeaderAcceptEncoding, "*, gzip;q=0.5")
+	n := setUpNegotiator(headers.AcceptEncoding, "*, gzip;q=0.5")
 
 	bestOffer, matched := n.Encoding([]string{"gzip", "deflate", "zlib"})
 
@@ -261,7 +262,7 @@ type CharsetSuite struct {
 }
 
 func (s CharsetSuite) TestEmpty() {
-	n := setUpNegotiator(HeaderAcceptCharset, "")
+	n := setUpNegotiator(headers.AcceptCharset, "")
 
 	_, matched := n.Charset([]string{})
 
@@ -269,7 +270,7 @@ func (s CharsetSuite) TestEmpty() {
 }
 
 func (s CharsetSuite) TestCaseInsensitive() {
-	n := setUpNegotiator(HeaderAcceptCharset, "ISO-8859-1")
+	n := setUpNegotiator(headers.AcceptCharset, "ISO-8859-1")
 
 	bestOffer, matched := n.Charset([]string{"ISO-8859-1"})
 
@@ -278,7 +279,7 @@ func (s CharsetSuite) TestCaseInsensitive() {
 }
 
 func (s CharsetSuite) TestUnMatched() {
-	n := setUpNegotiator(HeaderAcceptCharset, "ISO-8859-1,UTF-8")
+	n := setUpNegotiator(headers.AcceptCharset, "ISO-8859-1,UTF-8")
 
 	_, matched := n.Charset([]string{"ASCII"})
 
@@ -286,7 +287,7 @@ func (s CharsetSuite) TestUnMatched() {
 }
 
 func (s CharsetSuite) TestEmptyCharset() {
-	n := setUpNegotiator(HeaderAcceptCharset, "UTF-8;q=0")
+	n := setUpNegotiator(headers.AcceptCharset, "UTF-8;q=0")
 
 	_, matched := n.Charset([]string{"UTF-8"})
 
@@ -294,7 +295,7 @@ func (s CharsetSuite) TestEmptyCharset() {
 }
 
 func (s CharsetSuite) TestOneMatch() {
-	n := setUpNegotiator(HeaderAcceptCharset, "UTF-8;q=0.2")
+	n := setUpNegotiator(headers.AcceptCharset, "UTF-8;q=0.2")
 
 	bestOffer, matched := n.Charset([]string{"UTF-8"})
 
@@ -303,7 +304,7 @@ func (s CharsetSuite) TestOneMatch() {
 }
 
 func (s CharsetSuite) TestMatchAsterisk() {
-	n := setUpNegotiator(HeaderAcceptCharset, "*")
+	n := setUpNegotiator(headers.AcceptCharset, "*")
 
 	bestOffer, matched := n.Charset([]string{"UTF-8", "ISO-8859-1"})
 
@@ -312,7 +313,7 @@ func (s CharsetSuite) TestMatchAsterisk() {
 }
 
 func (s CharsetSuite) TestFirstMatchAllAsterisk() {
-	n := setUpNegotiator(HeaderAcceptCharset, "*, UTF-8;q=0.5")
+	n := setUpNegotiator(headers.AcceptCharset, "*, UTF-8;q=0.5")
 
 	bestOffer, matched := n.Charset([]string{"UTF-8", "ISO-8859-1", "ASCII"})
 
@@ -321,7 +322,7 @@ func (s CharsetSuite) TestFirstMatchAllAsterisk() {
 }
 
 func (s CharsetSuite) TestHighOrderPreferred() {
-	n := setUpNegotiator(HeaderAcceptCharset, "UTF-8;q=0.6, ISO-8859-1;q=0.8, UTF-8;q=0.9")
+	n := setUpNegotiator(headers.AcceptCharset, "UTF-8;q=0.6, ISO-8859-1;q=0.8, UTF-8;q=0.9")
 
 	bestOffer, matched := n.Charset([]string{"UTF-8", "ISO-8859-1", "ASCII"})
 
diff --git a/parser_accept_test.go b/parser_accept_test.go
index a5dd253..4cecd6b 100644
--- a/parser_accept_test.go
+++ b/parser_accept_test.go
@@ -5,6 +5,7 @@ import (
 
 	"net/http"
 
+	"github.com/go-http-utils/headers"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 )
@@ -24,8 +25,8 @@ func (s *ParseAcceptTestSuite) SetupTest() {
 func (s *ParseAcceptTestSuite) TestEmpty() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(1, len(specs))
 
@@ -35,8 +36,8 @@ func (s *ParseAcceptTestSuite) TestEmpty() {
 func (s *ParseAcceptTestSuite) TestAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "*/*")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "*/*")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(1, len(specs))
 
@@ -46,8 +47,8 @@ func (s *ParseAcceptTestSuite) TestAsterisk() {
 func (s *ParseAcceptTestSuite) TestOneType() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "application/json")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "application/json")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(1, len(specs))
 
@@ -57,8 +58,8 @@ func (s *ParseAcceptTestSuite) TestOneType() {
 func (s *ParseAcceptTestSuite) TestOneTypeWithQZero() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "application/json;q=0")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "application/json;q=0")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(0, len(specs))
 }
@@ -66,8 +67,8 @@ func (s *ParseAcceptTestSuite) TestOneTypeWithQZero() {
 func (s *ParseAcceptTestSuite) TestSortByQ() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "application/json;q=0.2, text/html")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "application/json;q=0.2, text/html")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(2, len(specs))
 
@@ -78,8 +79,8 @@ func (s *ParseAcceptTestSuite) TestSortByQ() {
 func (s *ParseAcceptTestSuite) TestSuffixAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "text/*")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "text/*")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(1, len(specs))
 
@@ -89,8 +90,8 @@ func (s *ParseAcceptTestSuite) TestSuffixAsterisk() {
 func (s *ParseAcceptTestSuite) TestSortWithAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAccept, "text/plain, application/json;q=0.5, text/html, */*;q=0.1")
-	specs := s.parser.parse(HeaderAccept)
+	s.header.Set(headers.Accept, "text/plain, application/json;q=0.5, text/html, */*;q=0.1")
+	specs := s.parser.parse(headers.Accept)
 
 	assert.Equal(4, len(specs))
 
diff --git a/parser_charset_test.go b/parser_charset_test.go
index 0ea09f3..2a905bb 100644
--- a/parser_charset_test.go
+++ b/parser_charset_test.go
@@ -5,6 +5,7 @@ import (
 
 	"net/http"
 
+	"github.com/go-http-utils/headers"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 )
@@ -24,8 +25,8 @@ func (s *ParseCharsetTestSuite) SetupTest() {
 func (s *ParseCharsetTestSuite) TestEmpty() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptCharset, "")
-	specs := s.parser.parse(HeaderAcceptCharset)
+	s.header.Set(headers.AcceptCharset, "")
+	specs := s.parser.parse(headers.AcceptCharset)
 
 	assert.Equal(1, len(specs))
 
@@ -35,8 +36,8 @@ func (s *ParseCharsetTestSuite) TestEmpty() {
 func (s *ParseCharsetTestSuite) TestAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptCharset, "*")
-	specs := s.parser.parse(HeaderAcceptCharset)
+	s.header.Set(headers.AcceptCharset, "*")
+	specs := s.parser.parse(headers.AcceptCharset)
 
 	assert.Equal(1, len(specs))
 
@@ -46,8 +47,8 @@ func (s *ParseCharsetTestSuite) TestAsterisk() {
 func (s *ParseCharsetTestSuite) TestOneLanguage() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptCharset, "UTF-8;level=1.0")
-	specs := s.parser.parse(HeaderAcceptCharset)
+	s.header.Set(headers.AcceptCharset, "UTF-8;level=1.0")
+	specs := s.parser.parse(headers.AcceptCharset)
 
 	assert.Equal(1, len(specs))
 
@@ -57,8 +58,8 @@ func (s *ParseCharsetTestSuite) TestOneLanguage() {
 func (s *ParseCharsetTestSuite) TestOneLanguageWithQZero() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptCharset, "*, ISO-8859-1;level=0")
-	specs := s.parser.parse(HeaderAcceptCharset)
+	s.header.Set(headers.AcceptCharset, "*, ISO-8859-1;level=0")
+	specs := s.parser.parse(headers.AcceptCharset)
 
 	assert.Equal(1, len(specs))
 
@@ -68,8 +69,8 @@ func (s *ParseCharsetTestSuite) TestOneLanguageWithQZero() {
 func (s *ParseCharsetTestSuite) TestSortByQ() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptCharset, "*;level=0.8, ISO-8859-1, UTF-8")
-	specs := s.parser.parse(HeaderAcceptCharset)
+	s.header.Set(headers.AcceptCharset, "*;level=0.8, ISO-8859-1, UTF-8")
+	specs := s.parser.parse(headers.AcceptCharset)
 
 	assert.Equal(3, len(specs))
 
diff --git a/parser_encoding_test.go b/parser_encoding_test.go
index db3c571..4902131 100644
--- a/parser_encoding_test.go
+++ b/parser_encoding_test.go
@@ -5,6 +5,7 @@ import (
 
 	"net/http"
 
+	"github.com/go-http-utils/headers"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 )
@@ -24,8 +25,8 @@ func (s *ParseEncodingTestSuite) SetupTest() {
 func (s *ParseEncodingTestSuite) TestEmpty() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptEncoding, "")
-	specs := s.parser.parse(HeaderAcceptEncoding)
+	s.header.Set(headers.AcceptEncoding, "")
+	specs := s.parser.parse(headers.AcceptEncoding)
 
 	assert.Equal(1, len(specs))
 
@@ -35,8 +36,8 @@ func (s *ParseEncodingTestSuite) TestEmpty() {
 func (s *ParseEncodingTestSuite) TestAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptEncoding, "*")
-	specs := s.parser.parse(HeaderAcceptEncoding)
+	s.header.Set(headers.AcceptEncoding, "*")
+	specs := s.parser.parse(headers.AcceptEncoding)
 
 	assert.Equal(1, len(specs))
 
@@ -46,8 +47,8 @@ func (s *ParseEncodingTestSuite) TestAsterisk() {
 func (s *ParseEncodingTestSuite) TestOneEncoing() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptEncoding, "gzip")
-	specs := s.parser.parse(HeaderAcceptEncoding)
+	s.header.Set(headers.AcceptEncoding, "gzip")
+	specs := s.parser.parse(headers.AcceptEncoding)
 
 	assert.Equal(1, len(specs))
 
@@ -57,8 +58,8 @@ func (s *ParseEncodingTestSuite) TestOneEncoing() {
 func (s *ParseEncodingTestSuite) TestOneEncodingWithQZero() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptEncoding, "*, gzip;q=0")
-	specs := s.parser.parse(HeaderAcceptEncoding)
+	s.header.Set(headers.AcceptEncoding, "*, gzip;q=0")
+	specs := s.parser.parse(headers.AcceptEncoding)
 
 	assert.Equal(1, len(specs))
 
@@ -68,8 +69,8 @@ func (s *ParseEncodingTestSuite) TestOneEncodingWithQZero() {
 func (s *ParseEncodingTestSuite) TestSortByQ() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptEncoding, "*;q=0.8, defalte, gzip")
-	specs := s.parser.parse(HeaderAcceptEncoding)
+	s.header.Set(headers.AcceptEncoding, "*;q=0.8, defalte, gzip")
+	specs := s.parser.parse(headers.AcceptEncoding)
 
 	assert.Equal(3, len(specs))
 
diff --git a/parser_language_test.go b/parser_language_test.go
index 7a0db45..210599a 100644
--- a/parser_language_test.go
+++ b/parser_language_test.go
@@ -5,6 +5,7 @@ import (
 
 	"net/http"
 
+	"github.com/go-http-utils/headers"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 )
@@ -24,8 +25,8 @@ func (s *ParseLanguageTestSuite) SetupTest() {
 func (s *ParseLanguageTestSuite) TestEmpty() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptLanguage, "")
-	specs := s.parser.parse(HeaderAcceptLanguage)
+	s.header.Set(headers.AcceptLanguage, "")
+	specs := s.parser.parse(headers.AcceptLanguage)
 
 	assert.Equal(1, len(specs))
 
@@ -35,8 +36,8 @@ func (s *ParseLanguageTestSuite) TestEmpty() {
 func (s *ParseLanguageTestSuite) TestAsterisk() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptLanguage, "*")
-	specs := s.parser.parse(HeaderAcceptLanguage)
+	s.header.Set(headers.AcceptLanguage, "*")
+	specs := s.parser.parse(headers.AcceptLanguage)
 
 	assert.Equal(1, len(specs))
 
@@ -46,8 +47,8 @@ func (s *ParseLanguageTestSuite) TestAsterisk() {
 func (s *ParseLanguageTestSuite) TestOneLanguage() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptLanguage, "en")
-	specs := s.parser.parse(HeaderAcceptLanguage)
+	s.header.Set(headers.AcceptLanguage, "en")
+	specs := s.parser.parse(headers.AcceptLanguage)
 
 	assert.Equal(1, len(specs))
 
@@ -57,8 +58,8 @@ func (s *ParseLanguageTestSuite) TestOneLanguage() {
 func (s *ParseLanguageTestSuite) TestOneLanguageWithQZero() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptLanguage, "*, en;q=0")
-	specs := s.parser.parse(HeaderAcceptLanguage)
+	s.header.Set(headers.AcceptLanguage, "*, en;q=0")
+	specs := s.parser.parse(headers.AcceptLanguage)
 
 	assert.Equal(1, len(specs))
 
@@ -68,8 +69,8 @@ func (s *ParseLanguageTestSuite) TestOneLanguageWithQZero() {
 func (s *ParseLanguageTestSuite) TestSortByQ() {
 	assert := assert.New(s.T())
 
-	s.header.Set(HeaderAcceptLanguage, "*;q=0.8, en, es")
-	specs := s.parser.parse(HeaderAcceptLanguage)
+	s.header.Set(headers.AcceptLanguage, "*;q=0.8, en, es")
+	specs := s.parser.parse(headers.AcceptLanguage)
 
 	assert.Equal(3, len(specs))