Suparelay
Call ordinary phone numbers from a browser
VoIP
Make voice calls over internet networks using compatible applications, devices, and communication services.
ZippCall
Make international calls from your browser or phone using prepaid credit.
8x8
Business calling, meetings, and team messaging through 8x8 Work
Vonage
Business phone services, contact centers, and communication APIs
Ooma
Internet phone services for homes and business teams
Nextiva
Business calls, messages and customer conversations in one platform
Grasshopper
A separate business number for calls and texts on your devices