diff --git a/api.php b/api.php
index da6459d..1087842 100755
--- a/api.php
+++ b/api.php
@@ -23,6 +23,8 @@ DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
 OR OTHER DEALINGS IN THE SOFTWARE.
 */
+header('Content-Type: application/json');
+
 
 /**
  * @api {get} /api.php 01. Basic Information
diff --git a/include/Blacklist.php.save b/include/Blacklist.php.save
new file mode 100644
index 0000000..e69de29
diff --git a/include/Blacklist.php.save.1 b/include/Blacklist.php.save.1
new file mode 100644
index 0000000..53d5eff
--- /dev/null
+++ b/include/Blacklist.php.save.1
@@ -0,0 +1,31 @@
+<?php
+
+namespace Arionum;
+
+/**
+ * Class Blacklist
+ */
+final class Blacklist
+{
+    /**
+     * The official list of blacklisted public keys
+     */
+    public const PUBLIC_KEYS = [
+        // phpcs:disable Generic.Files.LineLength
+        'PZ8Tyr4Nx8MHsRAGMpZmZ6TWY63dXWSCvVQcHHCNLfiP9LmzWhhpCHx39Bhc67P5HMQM9cctEFvcsUdgrkGqy18taz9ZMrAGtq7NhBYpQ4ZTHkKYiZDaSUqQ' => 'Faucet Abuser',
+        'PZ8Tyr4Nx8MHsRAGMpZmZ6TWY63dXWSCxYDeQHk7Ke66UB2Un3UMmMoJ7RF5vDZXihdEXi8gk8ZBRAi35aFrER2ZLX1mgND7sLFXKETGTjRYjoHcuRNiJN1g' => 'Octaex Exchange',
+	
+        // phpcs:enable
+    ];
+
+    /**
+     * Check if a public key is blacklisted
+     *
+     * @param string $publicKey
+     * @return bool
+     */
+    public static function checkPublicKey(string $publicKey): bool
+    {
+        return key_exists($publicKey, static::PUBLIC_KEYS);
+    }
+}
diff --git a/peer.php b/peer.php
index ea686a7..e5f3844 100755
--- a/peer.php
+++ b/peer.php
@@ -24,6 +24,8 @@ OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
 OR OTHER DEALINGS IN THE SOFTWARE.
 */
 require_once("include/init.inc.php");
+header('Content-Type: application/json');
+
 $trx = new Transaction();
 $block = new Block();
 $q = $_GET['q'];