diff --git a/src/jwe.c b/src/jwe.c
index 9c0d017..29f08ca 100644
--- a/src/jwe.c
+++ b/src/jwe.c
@@ -210,7 +210,7 @@ static bool _cjose_jwe_malloc(size_t bytes, bool random, uint8_t **buffer, cjose
 static bool _cjose_jwe_build_hdr(cjose_jwe_t *jwe, cjose_err *err)
 {
     // serialize the header
-    char *hdr_str = json_dumps(jwe->hdr, JSON_ENCODE_ANY | JSON_PRESERVE_ORDER);
+    char *hdr_str = json_dumps(jwe->hdr, JSON_ENCODE_ANY | JSON_PRESERVE_ORDER | JSON_COMPACT);
     if (NULL == hdr_str)
     {
         CJOSE_ERROR(err, CJOSE_ERR_NO_MEMORY);
diff --git a/src/jws.c b/src/jws.c
index 88038e4..5a117eb 100644
--- a/src/jws.c
+++ b/src/jws.c
@@ -51,7 +51,7 @@ static bool _cjose_jws_build_hdr(cjose_jws_t *jws, cjose_header_t *header, cjose
     json_incref(jws->hdr);
 
     // base64url encode the header
-    char *hdr_str = json_dumps(jws->hdr, JSON_ENCODE_ANY | JSON_PRESERVE_ORDER);
+    char *hdr_str = json_dumps(jws->hdr, JSON_ENCODE_ANY | JSON_PRESERVE_ORDER | JSON_COMPACT);
     if (NULL == hdr_str)
     {
         CJOSE_ERROR(err, CJOSE_ERR_NO_MEMORY);