diff --git a/examples/function_test.go b/examples/function_test.go
index cd2c2d98..44c8c590 100644
--- a/examples/function_test.go
+++ b/examples/function_test.go
@@ -19,14 +19,18 @@ func TestCaseCallFunction(t *testing.T) {
 		TestSteps: []hrp.IStep{
 			hrp.NewStep("get with params").
 				GET("/get").
-				WithParams(map[string]interface{}{"foo1": "${gen_random_string($n)}", "foo2": "${max($a, $b)}"}).
+				WithParams(map[string]interface{}{"foo1": "${gen_random_string($n)}", "foo2": "${max($a, $b)}", "foo3": "Foo3"}).
 				WithHeaders(map[string]string{"User-Agent": "HttpRunnerPlus"}).
 				Extract().
 				WithJmesPath("body.args.foo1", "varFoo1").
 				Validate().
 				AssertEqual("status_code", 200, "check status code").
 				AssertLengthEqual("body.args.foo1", 5, "check args foo1").
-				AssertEqual("body.args.foo2", "12.3", "check args foo2"), // notice: request params value will be converted to string
+				AssertEqual("body.args.foo2", "12.3", "check args foo2").
+				AssertTypeMatch("body.args.foo3", "str", "check args foo3 is type string").
+				AssertStringEqual("body.args.foo3", "foo3", "check args foo3 case-insensitivity").
+				AssertContains("body.args.foo3", "Foo", "check contains ").
+				AssertContainedBy("body.args.foo3", "this is Foo3 test", "check contained by"), // notice: request params value will be converted to string
 			hrp.NewStep("post json data with functions").
 				POST("/post").
 				WithHeaders(map[string]string{"User-Agent": "HttpRunnerPlus"}).
diff --git a/internal/builtin/assertion.go b/internal/builtin/assertion.go
index 31110221..87e4709b 100644
--- a/internal/builtin/assertion.go
+++ b/internal/builtin/assertion.go
@@ -15,13 +15,16 @@ var Assertions = map[string]func(t assert.TestingT, expected interface{}, actual
 	"greater_or_equals": assert.GreaterOrEqual,
 	"less_or_equals":    assert.LessOrEqual,
 	"not_equal":         assert.NotEqual,
-	"contains":          assert.Contains,
+	"contained_by":  	 assert.Contains,
 	"regex_match":       assert.Regexp,
+	"type_match":        assert.IsType,
 	// custom assertions
 	"startswith":    StartsWith, // check if string starts with substring
 	"endswith":      EndsWith,   // check if string ends with substring
 	"length_equals": EqualLength,
 	"length_equal":  EqualLength, // alias for length_equals
+	"contains":      Contains,
+	"string_equals": EqualString,
 }
 
 func StartsWith(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
@@ -83,3 +86,20 @@ func convertInt(value interface{}) (int, error) {
 		return 0, fmt.Errorf("unsupported int convertion for %v(%T)", v, v)
 	}
 }
+
+// Contains assert whether actual
+func Contains(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
+	return assert.Contains(t, actual, expected, msgAndArgs)
+}
+
+func EqualString(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
+	if !assert.IsType(t, "string", actual, msgAndArgs) {
+		return false
+	}
+	if !assert.IsType(t, "string", expected, msgAndArgs) {
+		return false
+	}
+	actualString := actual.(string)
+	expectedString := expected.(string)
+	return assert.True(t, strings.EqualFold(actualString, expectedString), msgAndArgs)
+}
diff --git a/validate.go b/validate.go
index f5d67a8a..9748ac05 100644
--- a/validate.go
+++ b/validate.go
@@ -35,6 +35,28 @@ func (s *StepRequestValidation) AssertEqual(jmesPath string, expected interface{
 	return s
 }
 
+func (s *StepRequestValidation) AssertContains(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "contains",
+		Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
+func (s *StepRequestValidation) AssertTypeMatch(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "type_match",
+		Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
 func (s *StepRequestValidation) AssertStartsWith(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
 	v := Validator{
 		Check:   jmesPath,
@@ -67,3 +89,25 @@ func (s *StepRequestValidation) AssertLengthEqual(jmesPath string, expected inte
 	s.step.Validators = append(s.step.Validators, v)
 	return s
 }
+
+func (s *StepRequestValidation) AssertContainedBy(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "contained_by",
+		Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
+func (s *StepRequestValidation) AssertStringEqual(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "string_equals",
+		Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
\ No newline at end of file