[Hiring] Senior Software Engineer – Core VoIP / SIP Backbone @Practice By Numbers
Senior Software Engineer – Core VoIP / SIP Backbone @Practice By Numbers
Software Development
Salary usd 150,000 - 1..
Remote Location
🇺🇸 USA Only
Employment Type full-time
Posted YDay

[Hiring] Senior Software Engineer – Core VoIP / SIP Backbone @Practice By Numbers

YDay - Practice By Numbers is hiring a remote Senior Software Engineer – Core VoIP / SIP Backbone. 💸 Salary: usd 150,000 - 180,000 per year 📍Location: USA

Role Description

This role owns the design and implementation of the core VoIP/SIP telephony backbone for PBN, including SIP routing, media handling, scalability, and reliability. You 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. This is a senior individual contributor role with high ownership and direct impact on a product used by thousands of dental practices daily.

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, alerting, logging, and capacity planning for SIP signaling, RTP/media, and VoIP quality (MOS, jitter, packet loss).
  • Collaborate with product and operations teams to translate business requirements (IVRs, call queues, routing rules, AI agents) into resilient VoIP and backend designs.

Qualifications

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

Nice to Have

  • Experience with WebRTC, SIP over WebSockets, and browser/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/FreeSWITCH clusters on AWS/GCP, Kubernetes, service meshes).
  • Prior work building call center or CPaaS-style platforms, including programmable IVRs, queues, and analytics.

What Success Looks Like

  • A robust, observable VoIP backbone that sustains high call volumes with low failure rates and predictable call quality across geographies.
  • Rapid rollout of new telephony features (IVRs, routing rules, AI agents) through clean APIs and configuration-driven behavior rather than manual changes.
  • Demonstrated reduction in telephony incidents and MTTR through automation, strong monitoring, and clear runbooks.

Benefits

  • Competitive base salary (Salary range) + equity
  • Comprehensive medical, dental, and vision insurance
  • 401(k) with company match
  • Flexible PTO and paid holidays
  • Remote-first culture with team offsites
Before You Apply
🇺🇸 Be aware of the location restriction for this remote position: USA Only
Beware of scams! When applying for jobs, you should NEVER have to pay anything. Learn more.
Senior Software Engineer – Core VoIP / SIP Backbone @Practice By Numbers
Software Development
Salary usd 150,000 - 1..
Remote Location
🇺🇸 USA Only
Employment Type full-time
Posted YDay
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🇺🇸 Be aware of the location restriction for this remote position: USA Only
Beware of scams! When applying for jobs, you should NEVER have to pay anything. Learn more.
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Sent Follow-Up
Interview Scheduled
Interview Completed
Offer Accepted
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