diff --git a/core/src/main/java/net/smyler/terramap/http/HttpStatusCodes.java b/core/src/main/java/net/smyler/terramap/http/HttpStatusCodes.java
new file mode 100644
index 00000000..52b27ba5
--- /dev/null
+++ b/core/src/main/java/net/smyler/terramap/http/HttpStatusCodes.java
@@ -0,0 +1,85 @@
+package net.smyler.terramap.http;
+
+
+/**
+ * HTTP response codes.
+ *
+ * @see <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Status">MDN documentation</a>
+ */
+public final class HttpStatusCodes {
+
+    // Information responses
+    public static final int HTTP_CONTINUE = 100;
+    public static final int HTTP_SWITCHING_PROTOCOLS = 101;
+    public static final int HTTP_PROCESSING = 102;
+    public static final int HTTP_EARLY_HINTS = 103;
+
+    // Successful responses
+    public static final int HTTP_OK = 200;
+    public static final int HTTP_CREATED = 201;
+    public static final int HTTP_ACCEPTED = 202;
+    public static final int HTTP_NON_AUTHORITATIVE_INFORMATION = 203;
+    public static final int HTTP_NO_CONTENT = 204;
+    public static final int HTTP_RESET_CONTENT = 205;
+    public static final int HTTP_PARTIAL_CONTENT = 206;
+    public static final int HTTP_MULTI_STATUS = 207;
+    public static final int HTTP_ALREADY_REPORTED = 208;
+    public static final int HTTP_IM_USED = 209;
+
+    // Redirection message
+    public static final int HTTP_MULTIPLE_CHOICES = 300;
+    public static final int HTTP_MOVED_PERMANENTLY = 301;
+    public static final int HTTP_FOUND = 302;
+    public static final int HTTP_SEE_OTHER = 303;
+    public static final int HTTP_NOT_MODIFIED = 304;
+    public static final int HTTP_USE_PROXY = 305;
+    public static final int HTTP_UNUSED = 306;
+    public static final int HTTP_TEMPORARY_REDIRECT = 307;
+    public static final int HTTP_PERMANENT_REDIRECT = 308;
+
+    // Client error response
+    public static final int HTTP_BAD_REQUEST = 400;
+    public static final int HTTP_UNAUTHORIZED = 401;
+    public static final int HTTP_PAYMENT_REQUIRED = 402;
+    public static final int HTTP_FORBIDDEN = 403;
+    public static final int HTTP_NOT_FOUND = 404;
+    public static final int HTTP_METHOD_NOT_ALLOWED = 405;
+    public static final int HTTP_NOT_ACCEPTABLE = 406;
+    public static final int HTTP_PROXY_AUTHENTICATION_REQUIRED = 407;
+    public static final int HTTP_REQUEST_TIMEOUT = 408;
+    public static final int HTTP_CONFLICT = 409;
+    public static final int HTTP_GONE = 410;
+    public static final int HTTP_LENGTH_REQUIRED = 411;
+    public static final int HTTP_PRECONDITION_FAILED = 412;
+    public static final int HTTP_REQUEST_ENTITY_TOO_LARGE = 413;
+    public static final int HTTP_REQUEST_URI_TOO_LONG = 414;
+    public static final int HTTP_UNSUPPORTED_MEDIA_TYPE = 415;
+    public static final int HTTP_REQUESTED_RANGE_NOT_SATISFIABLE = 416;
+    public static final int HTTP_EXPECTATION_FAILED = 417;
+    public static final int HTTP_I_M_A_TEAPOT = 418;
+    public static final int HTTP_UNPROCESSABLE_ENTITY = 422;
+    public static final int HTTP_LOCKED = 423;
+    public static final int HTTP_FAILED_DEPENDENCY = 424;
+    public static final int HTTP_TOO_EARLY = 425;
+    public static final int HTTP_UPGRADE_REQUIRED = 426;
+    public static final int HTTP_PRECONDITION_REQUIRED = 428;
+    public static final int HTTP_TOO_MANY_REQUESTS = 429;
+    public static final int HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE = 431;
+    public static final int HTTP_UNAVAILABLE_FOR_LEGAL_REASONS = 432;
+
+    // Server error response
+    public static final int HTTP_INTERNAL_SERVER_ERROR = 500;
+    public static final int HTTP_NOT_IMPLEMENTED = 501;
+    public static final int HTTP_BAD_GATEWAY = 502;
+    public static final int HTTP_SERVICE_UNAVAILABLE = 503;
+    public static final int HTTP_GATEWAY_TIMEOUT = 504;
+    public static final int HTTP_HTTP_VERSION_NOT_SUPPORTED = 505;
+    public static final int HTTP_VARIANT_ALSO_NEGOTIATES = 506;
+    public static final int HTTP_INSUFFICIENT_STORAGE = 507;
+    public static final int HTTP_LOOP_DETECTED = 508;
+    public static final int HTTP_NOT_EXTENDED = 510;
+    public static final int HTTP_NETWORK_AUTHENTICATION_REQUIRED = 511;
+
+    private HttpStatusCodes() {}
+
+}
diff --git a/core/src/main/java/net/smyler/terramap/http/UserAgent.java b/core/src/main/java/net/smyler/terramap/http/UserAgent.java
new file mode 100644
index 00000000..fde99de2
--- /dev/null
+++ b/core/src/main/java/net/smyler/terramap/http/UserAgent.java
@@ -0,0 +1,48 @@
+package net.smyler.terramap.http;
+
+import net.smyler.smylib.SmyLib;
+import net.smyler.smylib.game.GameClient;
+import net.smyler.terramap.Terramap;
+
+import static java.lang.System.getProperty;
+
+public final class UserAgent {
+
+    public static String buildUserAgent(GameClient client, Terramap terramap) {
+        StringBuilder userAgent = new StringBuilder();
+        terramap.version();
+        SmyLib.getGameClient().modLoader();
+
+        userAgent.append(modString(terramap)).append(" ");
+
+        userAgent.append(loaderString(client)).append(" ");
+        userAgent.append(mcString(client)).append(" ");
+
+        return userAgent.toString();
+    }
+
+    private static String osString() {
+        return getProperty("os.name", "unknown");
+    }
+
+    private static String javaString() {
+        String version = getProperty("java.version");
+        return "Java" + (version != null ? "/" + version : "");
+    }
+
+    private static String mcString(GameClient client) {
+        return "Minecraft/" + client.gameVersion();
+    }
+
+    private static String loaderString(GameClient client) {
+        return client.modLoader();
+    }
+
+    private static String modString(Terramap terramap) {
+        return String.format("Terramap/%s (%s; %s; +https://github.com/SmylerMC/terramap)",
+                terramap.version(),
+                osString(),
+                javaString()
+        );
+    }
+}