diff --git a/controllers/routes.php b/controllers/routes.php
index cc9f87c..40380d8 100644
--- a/controllers/routes.php
+++ b/controllers/routes.php
@@ -11,5 +11,8 @@ function fromController(string $path) {
 return function(Router $router) {
     $router->addRoute(GET, "/", fromController("/GET"));
     $router->addRoute(GET, "/test", useRenderer(fromController("/test/GET")));
+
     $router->addRoute(GET, "/ipaddress", useRenderer(fromController("/ipaddress/GET")));
+
+    $router->addRoute(GET, "/whois", useRenderer(fromController("/whois/GET")));
 };
diff --git a/controllers/whois/GET.php b/controllers/whois/GET.php
new file mode 100644
index 0000000..0157c4d
--- /dev/null
+++ b/controllers/whois/GET.php
@@ -0,0 +1,71 @@
+<?php
+
+require_once(__DIR__ . "/settings.php");
+
+require_once(ROOT . "/utils/error.php");
+require_once(ROOT . "/utils/http.php");
+require_once(ROOT . "/utils/arrays.php");
+
+function getContactData(array $data) {
+    $contacts = [];
+
+    foreach ($data["entities"] as $entity) {
+        if (!key_exists("vcardArray", $entity))
+            continue;
+
+        $vcardArray = $entity["vcardArray"][1];
+        $fn = array_values(array_filter($vcardArray, fn(array $a) => $a[0] == "fn"))[0][3] ?? null;
+        $kind = array_values(array_filter($vcardArray, fn(array $a) => $a[0] == "kind"))[0][3] ?? null;
+        $email = array_map(fn(array $a) => $a[3], array_values(array_filter($vcardArray, fn(array $a) => $a[0] == "email")));
+        $adr = array_values(array_filter($vcardArray, fn(array $a) => $a[0] == "adr"))[0]["label"] ?? null;
+
+        $contacts[] = [
+            "handle" => $entity["handle"],
+            "roles" => $entity["roles"],
+            "function" => $fn,
+            "kind" => $kind,
+            "address" => $adr,
+            "email" => $email,
+        ];
+    }
+
+    return $contacts;
+}
+
+function whoisIp(string $ip) {
+    $data = json_decode(getRequest(RDAP_URL . "/ip/" . $ip), true);
+    return [
+        "query" => $ip,
+        "version" => $data["ipVersion"],
+        "network" => [
+            "name" => $data["name"],
+            "type" => $data["type"] ?? null,
+            "cidr" => $data["cidr0_cidrs"][0][$data["ipVersion"] . "prefix"] . "/" . $data["cidr0_cidrs"][0]["length"],
+            "startAddress" => $data["startAddress"],
+            "endAddress" => $data["endAddress"],
+            "status" => $data["status"],
+            "remarks" => $data["remarks"]["description"][0] ?? "",
+            "contacts" => getContactData($data),
+        ]
+    ];
+}
+
+return function (array $context) {
+    $result = null;
+
+    if (key_exists("ip", $_GET)) {
+        $ip = $_GET["ip"];
+        if (!filter_var($ip, FILTER_VALIDATE_IP)) {
+            setStatusCode(400);
+            $result = errorResponse("Invalid IP address", "Please provide a valid IP address.");
+        } else {
+            $result = whoisIp($ip);
+        }
+    } else {
+        setStatusCode(400);
+        $result = errorResponse("Unknown mode", "Please specify one of the following query parameters: ip");
+    }
+
+    $context["renderer"]($result);
+};
+
diff --git a/controllers/whois/settings.php b/controllers/whois/settings.php
new file mode 100644
index 0000000..084d753
--- /dev/null
+++ b/controllers/whois/settings.php
@@ -0,0 +1,3 @@
+<?php
+
+const RDAP_URL = "https://rdap-bootstrap.arin.net/bootstrap";
\ No newline at end of file
diff --git a/middleware/renderer.php b/middleware/renderer.php
index defc6d4..c5667c0 100644
--- a/middleware/renderer.php
+++ b/middleware/renderer.php
@@ -6,13 +6,7 @@ function useRenderer($handler, string $default = "JSON", string $query_param = "
     return function (array $context) use ($handler, $default, $query_param) {
         $rendererMap = require(ROOT . "/renderer/renderer.php");
 
-        $format = array_default($query_param, $_GET);
-        if (!$format || !key_exists(strtoupper($format), $rendererMap)) {
-            $format = $default;
-        }
-
-
-        $context["renderer"] = $rendererMap[strtoupper($format)];
+        $context["renderer"] = $rendererMap[strtoupper($_GET[$query_param] ?? "")] ?? $rendererMap[$default];
 
         $handler($context);
     };
diff --git a/renderer/JSON.php b/renderer/JSON.php
index a6da1f4..5a52ead 100644
--- a/renderer/JSON.php
+++ b/renderer/JSON.php
@@ -1,5 +1,6 @@
 <?php
 
 return function($data) {
-    echo json_encode($data);
+    header("Content-Type: application/json");
+    echo json_encode($data, JSON_PRETTY_PRINT);
 };
\ No newline at end of file
diff --git a/router/Router.php b/router/Router.php
index a0253ac..7456de6 100644
--- a/router/Router.php
+++ b/router/Router.php
@@ -1,6 +1,7 @@
 <?php
 
 require_once(ROOT . "/utils/arrays.php");
+require_once(ROOT . "/utils/error.php");
 
 const GET = "GET";
 const POST = "POST";
@@ -18,7 +19,7 @@ class Router {
 
     function __construct() {
         $this->notFoundHandler = function($context) {
-            header("HTTP/", true, 404);
+            setStatusCode(404);
             require(ROOT . "/templates/404.php");
         };
     }
diff --git a/utils/arrays.php b/utils/arrays.php
index 1ca50ea..0361edd 100644
--- a/utils/arrays.php
+++ b/utils/arrays.php
@@ -8,11 +8,3 @@ function &array_get_or_add($needle, array &$haystack, $default=null) {
         return $haystack[$needle];
     }
 }
-
-function array_default($needle, array $haystack, $default=null) {
-    if (key_exists($needle, $haystack)) {
-        return $haystack[$needle];
-    } else {
-        return $default;
-    }
-}
diff --git a/utils/error.php b/utils/error.php
new file mode 100644
index 0000000..bb7ffbd
--- /dev/null
+++ b/utils/error.php
@@ -0,0 +1,13 @@
+<?php
+
+function setStatusCode(int $status) {
+    header("HTTP/", true, $status);
+}
+
+function errorResponse(string $error, string $description) {
+    return [
+        "error" => $error,
+        "description" => $description,
+        "timestamp" => (new DateTime())->format("c")
+    ];
+}
\ No newline at end of file
diff --git a/utils/http.php b/utils/http.php
new file mode 100644
index 0000000..38822c7
--- /dev/null
+++ b/utils/http.php
@@ -0,0 +1,35 @@
+<?php
+
+function request(string $method, string $url, string $body = null, array $headers = []) {
+    $curlResource = curl_init();
+
+    curl_setopt($curlResource, CURLOPT_URL, $url);
+    curl_setopt($curlResource, CURLOPT_RETURNTRANSFER, true);
+    curl_setopt($curlResource, CURLOPT_CUSTOMREQUEST, $method);
+    curl_setopt($curlResource, CURLOPT_FOLLOWLOCATION, true);
+
+    if ($body)
+        curl_setopt($curlResource, CURLOPT_POSTFIELDS, $body);
+
+    if ($headers) {
+        if (!array_is_list($headers))
+            $headers = array_map(fn($k, $v) => $k . ": " . $v, array_keys($headers), array_values($headers));
+
+
+        curl_setopt($curlResource, CURLOPT_HTTPHEADER, $headers);
+    }
+
+    $result = curl_exec($curlResource);
+
+    curl_close($curlResource);
+
+    return $result;
+}
+
+function getRequest(string $url, array $headers = []) {
+    return request("GET", $url, null, $headers);
+}
+
+function postRequest(string $url, string $body = null, $headers = []) {
+    return request("POST", $url, $body, $headers);
+}
\ No newline at end of file