Telephony Engineer

Posted Yesterday
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Hiring Remotely in Portugal
Remote
Senior level
Artificial Intelligence • Information Technology • Cybersecurity
The Role
Design, modernize, and operate large-scale VoIP telephony infrastructure. Integrate telecom providers, build inbound/outbound call systems, optimize costs and resources, and develop integrations with AI platforms. Ensure reliability, scaling, and fault tolerance while participating in 2nd/3rd-level support and on-call rotation.
Summary Generated by Built In
Description

We're expanding the team and are looking for a Telephony Engineer.

Requirements
  • 5 to 10 years of experience in VoIP and telephony engineering
  • Deep understanding of SIP protocol including messaging, methods, response codes and SDP, as well as troubleshooting of signaling and media issues including NAT and RTP
  • Knowledge of FreeSWITCH/Asterisk/ or any other b2ua including architecture, dialplan development using Lua/XML/conf, configuration of SIP profiles, gateways and modules, performance optimization
  • Experience building utilities, tools, management services for VoIP infrastructure
  • Experience with any kind of programming language.
  • Solid understanding of networking including TCP IP, RTP RTCP and traffic analysis using tools such as tcpdump, Wireshark and sngrep
  • Strong Linux administration (Debian or Ubuntu)

Nice to have

  • Experience with Go language.
  • Experience with Kamailio/Opensips or rtpengine
  • Familiarity with CI CD, Docker, Ansible and Kubernetes
  • Experience with large scale telephony systems
  • Experience with ESL and Sofia knowledge
  • Experience with Node.js for integration services, event socket (ESL) interaction with FreeSWITCH and REST API development
  • Background in voice biometrics projects
Responsibilities
  • Design and modernization of the telephony infrastructure
  • Integration with telecom providers in the US, LATAM and Europe
  • Optimization of resources and telecom costs
  • Building call handling systems from scratch for both outbound and inbound traffic
  • Development of integration solutions with the AI platform
  • Driving reliability, scaling and fault tolerance
  • Working with high call volumes using Kamailio/OpenSIPS and rtpengine
  • Participate in 2d and 3d level support duties as well as on-call rotation
What we offer
  • The team has built award-winning AI products for tech corporations — devices, voice assistants, products that are actually in the world 
  • Cutting-edge tech stack: Speech Technologies, NLP, Generative AI (LLMs, diffusion models), voice-first agentic architecture with privacy-first and on-premises deployment
  • High engineering bar and real ownership — the team cares about what actually works in production, not what looks good in a demo, and you'll see the impact of your work directly 
  • Fast career progression — a senior-heavy team and a high volume of real problems means you grow faster than you would anywhere else 
  • Startup pace with enterprise stability — real clients, real revenue, no bureaucracy 
  • Fully remote across Europe
  • 21 vacation days + public holidays + 5 sick days 
  • Private English lessons via Preply
  • Participation in Employee Stock Ownership Plan (ESOP)

Skills Required

  • 5 to 10 years of experience in VoIP and telephony engineering
  • Deep understanding of SIP protocol including messaging, methods, response codes and SDP, troubleshooting signaling and media issues including NAT and RTP
  • Knowledge of FreeSWITCH, Asterisk, or other B2BUA including architecture, dialplan development using Lua/XML/conf, configuration of SIP profiles, gateways and modules, performance optimization
  • Experience building utilities, tools, management services for VoIP infrastructure
  • Experience with any programming language
  • Solid understanding of networking including TCP/IP, RTP/RTCP and traffic analysis using tools such as tcpdump, Wireshark and sngrep
  • Strong Linux administration (Debian or Ubuntu)
  • Experience with Go language
  • Experience with Kamailio/OpenSIPS or rtpengine
  • Familiarity with CI/CD, Docker, Ansible and Kubernetes
  • Experience with large scale telephony systems
  • Experience with ESL and Sofia
  • Experience with Node.js for integration services, ESL interaction and REST API development
  • Background in voice biometrics projects

Acclaim AI Compensation & Benefits Highlights

The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about Acclaim AI and has not been reviewed or approved by Acclaim AI.

  • Parental & Family Support Parental leave is explicitly listed on the company’s Wellfound profile. Feedback suggests family support is part of the baseline perks communicated publicly.
  • Leave & Time Off Breadth Generous vacation is highlighted on Wellfound. This points to broader time-off flexibility typical of startup-style packages.
  • Wellbeing & Lifestyle Benefits Professional development and company events are called out on Wellfound. These signals indicate investment in growth and team connection beyond core benefits.

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The Company
69 Employees

What We Do

Acclaim is a voice-first AI customer experience (CX) platform purpose-built for regulated industries including banking, fintech, healthcare, and insurance. It provides enterprises with goal-oriented AI agents that go beyond conversation to deliver agentic solutions that solve end-to-end business problems—orchestrating and executing complete customer workflows from outreach through resolution. Acclaim's solutions transform human-driven CX processes into AI-powered ones that are continuously learning and improving. Our platform helps organizations delight with human-quality conversations, accelerate revenue-driving interactions, and safeguard their data by maintaining strict compliance across every customer channel—creating more seamless customer experiences while improving the productivity and satisfaction of human agents. Built on a privacy-first architecture with on-premises or private cloud deployment, Acclaim ensures every interaction is secure, compliant, and delivers results that speak for themselves.

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