Looking for a modern typeface that looks great for headlines in UI? Try Questrial. It’s free on Google Fonts.

From Google Fonts:

Questrial is the perfect font for body text and headlines on a website. It's modern style, suited with past characteristics of great typefaces, make it highly readable in any context. The full-circle curves on many characters make Questrial a great font to blend seamlessly with other fonts while still maintaining it's uniqueness.

It is heavily influenced by Swiss design, similar to a grotesk style which is closely found in Helvetica. The numbers in Questrial are tabular figures so they can be used in tables and forms to enable maximum satisfaction.

Questrial language support includes African Latin and full coverage of Vietnamese, additional to all Western, Central, and South-Eastern European languages.

Questrial was designed by Joe Prince and Laura Meseguer.