shMessenger Alternatives

tomeko.net/software: SIP client for Windows.

Telephone is a VoIP program which allows you to make phone calls over the internet.

VoIPstudio is an award-winning VoIP system that offers businesses of all sizes a scalable communication solution. It’s inexpensive, easy-to-use, offers a full suite of PBX features, and is fully integrated for CRM.

Try for free paid Free Trial $4.99 / Monthly (User)

WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.

free

MicroSIP is a free portable SIP softphone for Windows based on PJSIP stack.

White-label VoIP Softphone with WebRTC and Auto-provisioning

Empower Creation and Ensure Brand Consistency. Build and Share libraries of visual assets with your entire team — all from your desktop.

Open Source

CommPeak’s Hosted Cloud IP-PBX is a web-based highly customizable and feature-rich solution - the ideal, low-cost solution for an enterprise of all sizes.

PhonerLite enables your PC to use it for internet telephony (VoIP , Voice over IP, SIP).

White-label softphone platform where you can create, test and deploy mobile and WebRTC endpoints in less than 30 minutes.

Free and open-source SIP/VoIP Client

Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.

Chat for distributed teams. Zulip combines the immediacy of real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones.

Open Source

Comwave is a state-of-the-art communication service and rich solution providing a platform that is designed for modern businesses to streamline their growth with an agile approach.