diff --git a/pkgs/checks/lib/src/extensions/core.dart b/pkgs/checks/lib/src/extensions/core.dart
index 8c6955d..2fe29a2 100644
--- a/pkgs/checks/lib/src/extensions/core.dart
+++ b/pkgs/checks/lib/src/extensions/core.dart
@@ -118,4 +118,46 @@
           actual: literal(actual), which: ['Does not contain $pattern']);
     });
   }
+
+  Check<int> get length => has((m) => m.length, 'length');
+
+  void isEmpty() {
+    context.expect(() => const ['is empty'], (actual) {
+      if (actual.isEmpty) return null;
+      return Rejection(actual: literal(actual), which: ['is not empty']);
+    });
+  }
+
+  void isNotEmpty() {
+    context.expect(() => const ['is not empty'], (actual) {
+      if (actual.isNotEmpty) return null;
+      return Rejection(actual: literal(actual), which: ['is empty']);
+    });
+  }
+
+  void startsWith(String other) {
+    context.expect(
+      () => ['starts with ${literal(other)}'],
+      (actual) {
+        if (actual.startsWith(other)) return null;
+        return Rejection(
+          actual: literal(actual),
+          which: ['does not start with ${literal(other)}'],
+        );
+      },
+    );
+  }
+
+  void endsWith(String other) {
+    context.expect(
+      () => ['ends with ${literal(other)}'],
+      (actual) {
+        if (actual.endsWith(other)) return null;
+        return Rejection(
+          actual: literal(actual),
+          which: ['does not end with ${literal(other)}'],
+        );
+      },
+    );
+  }
 }