About the Company

Practice by Numbers (PbN) is building medical AI SaaS for the U.S. dental market—software that helps dental teams run smoother, grow revenue, and improve patient experience. The platform unifies analytics, scheduling, communications, payments, and marketing automation into a single system, replacing scattered tools and manual workflows trusted by thousands of practices across North America.

PbN is mission-driven and execution-oriented: high ownership, tight cross-functional collaboration, and product work with clear, measurable impact. You'll get real autonomy and see direct results in a large, under-digitized healthcare vertical that's actively moving toward AI-first workflows.

Position Overview

This role owns the design and implementation of PbN's core VoIP/SIP telephony backbone—the infrastructure layer that powers calling, routing, and communication workflows for thousands of dental practices. You will architect and build carrier-grade SIP services in Golang on top of open-source components, and integrate the telephony stack with PbN's broader AI-first SaaS platform. The role reports to the Engineering India Head and sits at the intersection of deep infrastructure work and product-facing impact.

Responsibilities

Design and implement a carrier-grade SIP/VoIP core using Kamailio or 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 across multi-node SIP proxies, distributed media servers, and RTP proxies.
Implement and maintain dial plans, least-cost routing, DID management, class-4/class-5 switching logic, and integrations with upstream carriers and PSTN gateways.
Own security and robustness of the VoIP stack: TLS/SRTP, authentication, rate limiting, fraud detection hooks, and abuse controls.
Integrate the telephony backbone with PbN's SaaS platform via well-defined internal APIs and webhooks, covering user accounts, billing, analytics, and AI/automation flows.
Define and own monitoring, alerting, logging, and capacity planning for SIP signaling, RTP/media, and VoIP quality metrics (MOS, jitter, packet loss).

Must-Have Requirements

7–10 years of software development experience with at least 4–5 years building or operating large-scale VoIP/SIP systems in production.
Strong Golang skills including high-performance networked services, concurrent processing, and production-grade APIs.
Hands-on experience with at least one open-source SIP server—Kamailio, OpenSIPS, or Asterisk—including configuration, routing logic, and packet-level troubleshooting.
Deep understanding of SIP, RTP, SDP, NAT traversal, registrar/registration flows, B2BUA vs. proxy behavior, and SBC concepts.
Proven ability to design and operate highly available telephony backbones: clustering, health checks, load balancing, and graceful failover.
Strong Linux and networking fundamentals—iptables, firewalls, TCP/UDP, QoS—with comfort debugging at packet level using tcpdump or Wireshark.
Experience integrating VoIP platforms with RESTful backends and databases (PostgreSQL or MariaDB/MySQL) and message queues for control and billing workflows.

Nice to Have

Experience with WebRTC, SIP over WebSockets, and browser or mobile softphone integrations.
Familiarity with VoIP billing, rating engines, CDR processing, and reseller hierarchies (class-4/class-5 softswitch products or similar).
Cloud-native deployment of VoIP stacks—containerized Kamailio or FreeSWITCH clusters on AWS or GCP, Kubernetes, service meshes.
Prior work building call center or CPaaS-style platforms including programmable IVRs, call queues, and analytics.

What We Offer

End-to-end ownership of a mission-critical infrastructure layer powering thousands of live dental practices across North America.
Direct exposure to AI-first product evolution—conversational automation, intelligent call routing, and front-office workflow integration.
High-autonomy environment with tight cross-functional collaboration across product, engineering, and operations.
Competitive compensation commensurate with senior infrastructure expertise.
Flexible scheduling within a fast-moving, execution-oriented team with real measurable impact.

Senior Software Engineer - VOIP / SIP