Roboto in action on sipapp.io

.header-1 { font-family: Roboto, sans-serif; font-size: 32px; font-style: normal; font-weight: 200; letter-spacing: 0.64px; line-height: 38.4px; text-transform: none; color: #29007A; }
.header-2 { font-family: Roboto, sans-serif; font-size: 19.2px; font-style: normal; font-weight: 300; letter-spacing: 0.384px; line-height: normal; text-transform: none; color: #29007A; }
.content-1 { font-family: Roboto, sans-serif; font-size: 14.4px; font-style: normal; font-weight: 300; letter-spacing: 0.288px; line-height: 22.32px; text-transform: none; color: #787676; }
Roboto is available from Font Squirrel, Google Web Fonts and Typekit.
Found by @mikesten on 20 Mar 2017.

Roboto