diff --git a/src/filter.js b/src/filter.js
index c0525a4..a5e3c87 100644
--- a/src/filter.js
+++ b/src/filter.js
@@ -1,10 +1,31 @@
-
-
+/**
+ *
+ *
+ *
+ */
 class Filter {
+
+	/**
+	 *
+	 *
+	 *  @param {object} options
+	 *
+	 */
 	constructor(options) {
 		this._options = options
 	}
 
+	/**
+     *  if result with key is equal
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
 	_eq(value, key, result) {
 		let isValid = false
 
@@ -15,6 +36,17 @@ class Filter {
 		return isValid
 	}
 
+	/**
+	 *  if result with key is not equal
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
 	_neq(value, key, result) {
 		let isValid = false
 
@@ -25,6 +57,18 @@ class Filter {
 		return isValid
 	}
 
+	/**
+     *  if result with key has a single value or
+	 *  value from value
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
 	_in(value, key, result) {
 		let isValid = false
 
@@ -55,7 +99,137 @@ class Filter {
 	}
 
 	/**
+     *  if result with key is lesser
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_lt(value, key, result) {
+		let isValid = false
+
+		if (result[key] > value) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  if result with key is lesser or equal
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_lte(value, key, result) {
+		let isValid = false
+
+		if (result[key] >= value) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  if result with key is greater
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_gt(value, key, result) {
+		let isValid = false
+
+		if (result[key] < value) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  if result with key is greater or equal
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_gte(value, key, result) {
+		let isValid = false
+
+		if (result[key] <= value) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  if result with key is null
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_null(value, key, result) {
+		let isValid = false
+
+		if (!result[key]) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  if result with key is not null
+	 *
+	 *
+	 *  @param {object} value
+	 *  @param {string} key
+	 *  @param {object} result
+	 *
+	 *  @return {boolean}
+	 *
+	 */
+	_nnull(value, key, result) {
+		let isValid = false
+
+		if (result[key]) {
+			isValid = true
+		}
+
+		return isValid
+	}
+
+	/**
+     *  run through all options with single result
+	 *
 	 *
+	 *  @param {object} result
+	 *  @return {boolean}
 	 *
 	 */
 	validate(result) {
diff --git a/test/filter.js b/test/filter.js
index d9aaf8a..d50f036 100644
--- a/test/filter.js
+++ b/test/filter.js
@@ -72,4 +72,94 @@ describe('Filter', function () {
 
 		assert.equal(filter.validate(data), true)
 	})
+
+	it('_lt', function() {
+
+		const filter = new Filter({
+			number: {
+				_lt: 100
+			}
+		})
+
+		const data = {
+			number: 150
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
+
+	it('_lte', function() {
+
+		const filter = new Filter({
+			number: {
+				_lte: 150
+			}
+		})
+
+		const data = {
+			number: 150
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
+
+	it('_gt', function() {
+
+		const filter = new Filter({
+			number: {
+				_gt: 150
+			}
+		})
+
+		const data = {
+			number: 100
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
+
+	it('_gte', function() {
+
+		const filter = new Filter({
+			number: {
+				_gte: 150
+			}
+		})
+
+		const data = {
+			number: 100
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
+
+	it('_null', function() {
+
+		const filter = new Filter({
+			not: {
+				_null: true
+			}
+		})
+
+		const data = {
+
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
+
+	it('_nnull', function() {
+
+		const filter = new Filter({
+			not: {
+				_nnull: true
+			}
+		})
+
+		const data = {
+			not: true
+		}
+
+		assert.equal(filter.validate(data), true)
+	})
 })