As the Rambam states in H. A"Z 12:5:

ומותר ללקוט הפיאות במספריים, לא נאסר אלא השחתה של תער

One may remove the [hairs from] the corners [of our heads] with scissors. The prohibition applies only to total removal with a razor.

This is based on the sugya in Makkoth 20a which rules in accordance with Rabbanan.

As the Rambam states in H. A"Z 12:8:

ואינו חייב עד שיגלחנו בתער--שנאמר "ולא תשחית, את פאת זקנך" (ויקרא יט,כז), גילוח שיש בו השחתה; לפיכך אם גילח זקנו במספריים, פטור. ואין המתגלח לוקה, עד שיסייע.

One is liable only when one shaves with a razor, as [implied by Leviticus 19:27]: "Do not destroy the corners of your beard." [We can infer that this applies only] to shaving which utterly destroys [one's facial hair]. Therefore, a person who removes his beard with scissors is exempt.

Some debate whether it is patur aval assur or that that there is a free license altogether (Sefer ha-Hinukh vs Beth Yosef).