diff --git a/docs/0003-open-online-config-v1-vmess.md b/docs/0003-open-online-config-v1-vmess.md
new file mode 100644
index 0000000..cbef78b
--- /dev/null
+++ b/docs/0003-open-online-config-v1-vmess.md
@@ -0,0 +1,54 @@
+# Open Online Config 1: VMess
+
+## 1. Overview
+
+This document defines the JSON document format for VMess AEAD configurations in Open Online Config 1.
+
+## 2. API Specification
+
+Request:
+
+``` http
+GET /<secret>/ooc/v1/<user_id>
+```
+
+Response JSON:
+
+``` json
+{
+    "protocols": [ "vmess" ],
+    "vmess": [
+        {
+            "id": "27b8a625-4f4b-4428-9f0f-8a2317db7c79",
+            "name": "ServerName",
+            "address": "example.com",
+            "port": 8388,
+            "security": "auto",
+            "password": "example",
+            "stream": {
+                "network": "tcp",
+                "security": "none",
+            },
+            "mux": 0,
+        }
+    ]
+}
+```
+
+The protocol name is `vmess`. Custom fields are allowed but MUST NOT be related to the protocol itself.
+
+Required fields:
+
+- `id`: UUID of the server. Used by clients to distinguish and persist servers when reloading.
+- `name`: Server name.
+- `address`: Server address. Do not enclose IPv6 addresses in brackets. Examples: `example.com`, `1.1.1.1`, `2001:db8::1`.
+- `port`: Server port number.
+- `security`: encryption method. Valid values: `auto`, `zero`, `none`, `aes-128-gcm`, `chacha20-poly1305`.
+- `password`: Password. Not the derived key.
+
+Optional fields:
+
+- `stream`: StreamSettingsObject.
+    - `network`: Stream Netwokr Type. Valid values: `tcp`, `kcp`, `ws`, `http`, `quic`, `grpc`.
+    - `security`: Transport layer encryption. Valid values: `none`, `tls`.
+- `mux`: 0 Means disabled. Available range 1 - 8.
\ No newline at end of file