diff --git a/package-lock.json b/package-lock.json
index e9214bc..e51a154 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -24,6 +24,7 @@
         "got": "^11.8.2",
         "hcaptcha": "^0.1.0",
         "image-pixels": "^1.1.1",
+        "joi": "^17.6.1",
         "kaitai-struct": "^0.9.0",
         "moment": "^2.24.0",
         "moment-timezone": "^0.5.27",
@@ -51,6 +52,19 @@
         "node": ">=0.1.90"
       }
     },
+    "node_modules/@hapi/hoek": {
+      "version": "9.3.0",
+      "resolved": "https://registry.npmjs.org/@hapi/hoek/-/hoek-9.3.0.tgz",
+      "integrity": "sha512-/c6rf4UJlmHlC9b5BaNvzAcFv7HZ2QHaV0D4/HNlBdvFnvQq8RI4kYdhyPCl7Xj+oWvTWQ8ujhqS53LIgAe6KQ=="
+    },
+    "node_modules/@hapi/topo": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/@hapi/topo/-/topo-5.1.0.tgz",
+      "integrity": "sha512-foQZKJig7Ob0BMAYBfcJk8d77QtOe7Wo4ox7ff1lQYoNNAb6jwcY1ncdoy2e9wQZzvNy7ODZCYJkK8kzmcAnAg==",
+      "dependencies": {
+        "@hapi/hoek": "^9.0.0"
+      }
+    },
     "node_modules/@oozcitak/dom": {
       "version": "0.0.11",
       "resolved": "https://registry.npmjs.org/@oozcitak/dom/-/dom-0.0.11.tgz",
@@ -217,6 +231,24 @@
         "@redis/client": "^1.0.0"
       }
     },
+    "node_modules/@sideway/address": {
+      "version": "4.1.4",
+      "resolved": "https://registry.npmjs.org/@sideway/address/-/address-4.1.4.tgz",
+      "integrity": "sha512-7vwq+rOHVWjyXxVlR76Agnvhy8I9rpzjosTESvmhNeXOXdZZB15Fl+TI9x1SiHZH5Jv2wTGduSxFDIaq0m3DUw==",
+      "dependencies": {
+        "@hapi/hoek": "^9.0.0"
+      }
+    },
+    "node_modules/@sideway/formula": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@sideway/formula/-/formula-3.0.0.tgz",
+      "integrity": "sha512-vHe7wZ4NOXVfkoRb8T5otiENVlT7a3IAiw7H5M2+GO+9CDgcVUUsX1zalAztCmwyOr2RUTGJdgB+ZvSVqmdHmg=="
+    },
+    "node_modules/@sideway/pinpoint": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@sideway/pinpoint/-/pinpoint-2.0.0.tgz",
+      "integrity": "sha512-RNiOoTPkptFtSVzQevY/yWtZwf/RxyVnPy/OcA9HBM3MlGDnBEYL5B41H0MTn0Uec8Hi+2qUtTfG2WWZBmMejQ=="
+    },
     "node_modules/@sindresorhus/is": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/@sindresorhus/is/-/is-4.0.1.tgz",
@@ -1902,6 +1934,18 @@
         "node": ">= 0.6.0"
       }
     },
+    "node_modules/joi": {
+      "version": "17.6.1",
+      "resolved": "https://registry.npmjs.org/joi/-/joi-17.6.1.tgz",
+      "integrity": "sha512-Hl7/iBklIX345OCM1TiFSCZRVaAOLDGlWCp0Df2vWYgBgjkezaR7Kvm3joBciBHQjZj5sxXs859r6eqsRSlG8w==",
+      "dependencies": {
+        "@hapi/hoek": "^9.0.0",
+        "@hapi/topo": "^5.0.0",
+        "@sideway/address": "^4.1.3",
+        "@sideway/formula": "^3.0.0",
+        "@sideway/pinpoint": "^2.0.0"
+      }
+    },
     "node_modules/jpeg-js": {
       "version": "0.3.7",
       "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.3.7.tgz",
@@ -3629,6 +3673,19 @@
       "integrity": "sha512-ooWCrlZP11i8GImSjTHYHLkvFDP48nS4+204nGb1RiX/WXYHmJA2III9/e2DWVabCESdW7hBAEzHRqUn9OUVvQ==",
       "dev": true
     },
+    "@hapi/hoek": {
+      "version": "9.3.0",
+      "resolved": "https://registry.npmjs.org/@hapi/hoek/-/hoek-9.3.0.tgz",
+      "integrity": "sha512-/c6rf4UJlmHlC9b5BaNvzAcFv7HZ2QHaV0D4/HNlBdvFnvQq8RI4kYdhyPCl7Xj+oWvTWQ8ujhqS53LIgAe6KQ=="
+    },
+    "@hapi/topo": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/@hapi/topo/-/topo-5.1.0.tgz",
+      "integrity": "sha512-foQZKJig7Ob0BMAYBfcJk8d77QtOe7Wo4ox7ff1lQYoNNAb6jwcY1ncdoy2e9wQZzvNy7ODZCYJkK8kzmcAnAg==",
+      "requires": {
+        "@hapi/hoek": "^9.0.0"
+      }
+    },
     "@oozcitak/dom": {
       "version": "0.0.11",
       "resolved": "https://registry.npmjs.org/@oozcitak/dom/-/dom-0.0.11.tgz",
@@ -3761,6 +3818,24 @@
       "integrity": "sha512-OFp0q4SGrTH0Mruf6oFsHGea58u8vS/iI5+NpYdicaM+7BgqBZH8FFvNZ8rYYLrUO/QRqMq72NpXmxLVNcdmjA==",
       "requires": {}
     },
+    "@sideway/address": {
+      "version": "4.1.4",
+      "resolved": "https://registry.npmjs.org/@sideway/address/-/address-4.1.4.tgz",
+      "integrity": "sha512-7vwq+rOHVWjyXxVlR76Agnvhy8I9rpzjosTESvmhNeXOXdZZB15Fl+TI9x1SiHZH5Jv2wTGduSxFDIaq0m3DUw==",
+      "requires": {
+        "@hapi/hoek": "^9.0.0"
+      }
+    },
+    "@sideway/formula": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@sideway/formula/-/formula-3.0.0.tgz",
+      "integrity": "sha512-vHe7wZ4NOXVfkoRb8T5otiENVlT7a3IAiw7H5M2+GO+9CDgcVUUsX1zalAztCmwyOr2RUTGJdgB+ZvSVqmdHmg=="
+    },
+    "@sideway/pinpoint": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@sideway/pinpoint/-/pinpoint-2.0.0.tgz",
+      "integrity": "sha512-RNiOoTPkptFtSVzQevY/yWtZwf/RxyVnPy/OcA9HBM3MlGDnBEYL5B41H0MTn0Uec8Hi+2qUtTfG2WWZBmMejQ=="
+    },
     "@sindresorhus/is": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/@sindresorhus/is/-/is-4.0.1.tgz",
@@ -5128,6 +5203,18 @@
       "resolved": "https://registry.npmjs.org/jmespath/-/jmespath-0.15.0.tgz",
       "integrity": "sha1-o/Iiqarp+Wb10nx5ZRDigJF2Qhc="
     },
+    "joi": {
+      "version": "17.6.1",
+      "resolved": "https://registry.npmjs.org/joi/-/joi-17.6.1.tgz",
+      "integrity": "sha512-Hl7/iBklIX345OCM1TiFSCZRVaAOLDGlWCp0Df2vWYgBgjkezaR7Kvm3joBciBHQjZj5sxXs859r6eqsRSlG8w==",
+      "requires": {
+        "@hapi/hoek": "^9.0.0",
+        "@hapi/topo": "^5.0.0",
+        "@sideway/address": "^4.1.3",
+        "@sideway/formula": "^3.0.0",
+        "@sideway/pinpoint": "^2.0.0"
+      }
+    },
     "jpeg-js": {
       "version": "0.3.7",
       "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.3.7.tgz",
diff --git a/package.json b/package.json
index 089fa2e..79d5354 100644
--- a/package.json
+++ b/package.json
@@ -35,6 +35,7 @@
     "got": "^11.8.2",
     "hcaptcha": "^0.1.0",
     "image-pixels": "^1.1.1",
+    "joi": "^17.6.1",
     "kaitai-struct": "^0.9.0",
     "moment": "^2.24.0",
     "moment-timezone": "^0.5.27",
diff --git a/src/services/api/routes/v1/user.js b/src/services/api/routes/v1/user.js
index e3a8241..07c014d 100644
--- a/src/services/api/routes/v1/user.js
+++ b/src/services/api/routes/v1/user.js
@@ -1,7 +1,17 @@
 const router = require('express').Router();
+const joi = require('joi');
 const { PNID } = require('../../../../models/pnid');
 const config = require('../../../../../config.json');
 
+// TODO: Extend this later with more settings
+const userSchema = joi.object({
+	mii: joi.object({
+		name: joi.string(),
+		primary: joi.string(),
+		data: joi.string(),
+	})
+});
+
 /**
  * [GET]
  * Implementation of for: https://api.pretendo.cc/v1/user
@@ -66,12 +76,14 @@ router.post('/', async (request, response) => {
 		});
 	}
 
-	if (body.mii && typeof body.mii === 'object' && body.mii.name && body.mii.primary && body.mii.data) {
-		const name = body.mii.name;
-		const primary = body.mii.primary;
-		const data = body.mii.data;
+	const valid = userSchema.validate(body);
 
-		await pnid.updateMii({ name, primary, data });
+	if (valid.error) {
+		return response.status(400).json({
+			app: 'api',
+			status: 400,
+			error: valid.error
+		});
 	}
 
 	const { pid } = pnid;