Pollen is a free, open-source variable typeface. One font file gives you weights 400 to 700 and a roundness axis that goes from sharp, Inter-like corners to fully soft ones, so you can tune both from CSS.

It builds on Open Runde by Laurids Kern, which is itself a rounded version of Inter by Rasmus Andersson. I combined Open Runde's four separate weights into one variable font and added the roundness axis. Pollen covers Latin, Greek and Cyrillic (2,494 characters), and it ships as WOFF2 for the web and TTF for desktop apps.

It's licensed under the SIL Open Font License, so you can use it in personal and commercial work.