Senior Software Engineer – Core VoIP / SIP Backbone
Practice by Numbers (PBN) | Gurugram / Kolkata, India

About Practice by Numbers
Practice by Numbers is a leading dental practice management SaaS platform serving over
1,500 dental practices across North America, providing practice management, VOIP telephony,
payments, and advanced analytics. The platform is evolving into an AI‐first product, adding
conversational automation and intelligent communication workflows for patients and front-office
teams.

About the Role
This role owns the design and implementation of the core VoIP/SIP telephony backbone for
PBN, including SIP routing, media handling, scalability, and reliability. The engineer will architect
and build Golang‐based SIP services and control planes on top of open‐source components
such as Kamailio (or similar SIP server), FreeSWITCH/OpenSIPS, and related media/RTP
proxies.

Location: Gurugram / Kolkata, India
Work Mode: In-office
Employment type: Full time

Key Responsibilities
- Design and implement a carrier‐grade SIP/VoIP core using components like




Kamailio/OpenSIPS for SIP signaling and FreeSWITCH or similar for media and
application services.
- Build Golang‐based SIP services (registrar, SBC‐like components, routing logic,
monitoring daemons) and internal APIs to control routing, policies, and provisioning.
- Configure and operate SIP load balancing, failover, and high‐availability setups
(multi‐node SIP proxies, distributed media servers, RTP proxies).
- Implement and maintain dial plans, least‐cost routing, DID management, class‐4/class‐5
style switching logic, and integration with upstream carriers and PSTN gateways.
- Own security and robustness of the VoIP stack: TLS/SRTP, authentication/authorization,
rate limiting, fraud detection hooks, and abuse controls.
- Integrate the telephony backbone with PBN’s SaaS platform (user accounts, billing,
analytics, AI/automation flows) via well‐defined internal APIs and webhooks.
- Define monitoring, alertin

📌 Senior Software Engineer – Core VoIP (Gurugram)
🏢 Practice by Numbers
📍 Gurugram