diff --git a/src/api/validator.ts b/src/api/validator.ts
new file mode 100644
index 000000000..d75fe6420
--- /dev/null
+++ b/src/api/validator.ts
@@ -0,0 +1,53 @@
+import * as mongo from 'mongodb';
+
+type Type = 'id' | 'string' | 'number' | 'boolean' | 'array' | 'object';
+
+export default <T>(value: any, isRequired: boolean, type: Type): [T, string] => {
+	if (value === undefined || value === null) {
+		if (isRequired) {
+			return [null, 'is-required']
+		} else {
+			return [null, null]
+		}
+	}
+
+	switch (type) {
+		case 'id':
+			if (typeof value != 'string' || !mongo.ObjectID.isValid(value)) {
+				return [null, 'incorrect-id'];
+			}
+			break;
+
+		case 'string':
+			if (typeof value != 'string') {
+				return [null, 'must-be-a-string'];
+			}
+			break;
+
+		case 'number':
+			if (!Number.isFinite(value)) {
+				return [null, 'must-be-a-number'];
+			}
+			break;
+
+		case 'boolean':
+			if (typeof value != 'boolean') {
+				return [null, 'must-be-an-boolean'];
+			}
+			break;
+
+		case 'array':
+			if (!Array.isArray(value)) {
+				return [null, 'must-be-an-array'];
+			}
+			break;
+
+		case 'object':
+			if (typeof value != 'object') {
+				return [null, 'must-be-an-onject'];
+			}
+			break;
+	}
+
+	return [value, null];
+};