Bring a large pot of salted water to a boil.
Add the rotini pasta and cook according to package instructions until al dente.
Drain the pasta and rinse it under cold water.
In a large mixing bowl, combine the cooked pasta, cherry tomatoes, cucumber, and bell pepper.
Add the black olives and red onion.
In a separate bowl, whisk together the olive oil, balsamic vinegar, salt, and pepper.
Pour the dressing over the salad and toss gently to combine.
Fold in the feta cheese and fresh basil.
Taste and adjust seasoning if needed.
Serve chilled or at room temperature.