Your other number is calling.
With patented technology, the Sideline app gives you a second phone number that’s just as reliable as your first.
With patented technology, the Sideline app gives you a second phone number that’s just as reliable as your first.Get Started for Free Get Started for Free
Call with confidence.
Sideline works with your existing carrier network (not VoIP) to deliver great call quality anywhere your phone has service.
See which number is ringing.
Custom caller ID makes it clear which number is ringing so it's easy to prioritize calls and answer accordingly.
Protect your privacy.
With your primary number separate, Sideline lets you stay safe and anonymous whenever you need to.
Powerful features built for your mobile life.
Get a second phone line for calls, texts, voicemail, and more.
Sideline detects spam calls, telemarketers, and potential fraud so you can easily avoid them.
Send an automated text reply to any missed calls or messages.
Record a separate greeting so people can leave a message after the beep.
Send unlimited SMS, MMS, and group messages.
Take the conversation to a bigger keyboard with the web texting portal.
Already have a second number? Bring it to Sideline from another device or landline.
Ring & Text Tones
Differentiate between numbers with unique ring and text tones.