diff --git a/src/api/validator2.ts b/src/api/validator2.ts
new file mode 100644
index 0000000000..057875f80b
--- /dev/null
+++ b/src/api/validator2.ts
@@ -0,0 +1,99 @@
+import * as mongo from 'mongodb';
+import hasDuplicates from '../common/has-duplicates';
+
+type CustomValidator<T> = (value: T) => boolean | string;
+
+interface Validator {
+	get: () => [any, string];
+
+	required: () => Validator;
+
+	validate: (validator: CustomValidator<any>) => Validator;
+}
+
+class ValidatorCore implements Validator {
+	value: any;
+	error: string;
+
+	required() {
+		if (this.error === null && this.value === null) {
+			this.error = 'required';
+		}
+		return this;
+	}
+
+	get(): [any, string] {
+		return [this.value, this.error];
+	}
+
+	validate(validator: any) {
+		if (this.error || this.value === null) return this;
+		const result = validator(this.value);
+		if (result === false) {
+			this.error = 'invalid-format';
+		} else if (typeof result == 'string') {
+			this.error = result;
+		}
+		return this;
+	}
+}
+
+class NumberValidator extends ValidatorCore {
+	value: number;
+	error: string;
+
+	constructor(value) {
+		super();
+		if (value === undefined || value === null) {
+			this.value = null;
+		} else if (!Number.isFinite(value)) {
+			this.error = 'must-be-a-number';
+		} else {
+			this.value = value;
+		}
+	}
+
+	range(min: number, max: number) {
+		if (this.error || this.value === null) return this;
+		if (this.value < min || this.value > max) {
+			this.error = 'invalid-range';
+		}
+		return this;
+	}
+
+	required() {
+		return super.required();
+	}
+
+	get(): [number, string] {
+		return super.get();
+	}
+
+	validate(validator: CustomValidator<number>) {
+		return super.validate(validator);
+	}
+}
+
+const it = (value) => {
+	return {
+		must: {
+			be: {
+				a: {
+					string: 0,
+					number: () => new NumberValidator(value),
+					boolean: 0,
+					set: 0
+				},
+				an: {
+					id: 0,
+					array: 0,
+					object: 0
+				}
+			}
+		}
+	};
+};
+
+export default it;
+
+const [n, e] = it(42).must.be.a.number().required().range(10, 70).validate(x => x != 21).get();