Senior Manual QA Engineer – VoIP, Voice, Real-Time Communications

Posted 36ds ago

Employment Information

Education
Salary
Experience
Job Type

Report this job

Job expired or something wrong with this job?

Job Description

QA Engineer at MMDSmart analyzing business and technical requirements in VoIP and real-time communication systems. Collaborating with agile teams to enhance quality and system resilience.

Responsibilities:

  • You will analyze business requirements and technical specifications for both web interfaces and backend, proactively challenging architectural assumptions to prevent issues before they reach production.
  • You will act as a "Voice System Investigator" performing deep-dive analysis of complex call flows and media streams using packet captures (PCAPs) and server logs to identify the root cause of signaling and audio defects.
  • You will design and execute advanced test strategies that cover the entire communication lifecycle, ensuring seamless integration between WebRTC components, IVR logic, ACD routing, and call recording systems.
  • You will investigate the intersection of web application states and real-time media, debugging issues like UI/UX synchronization with agent states, call control race conditions, and WebRTC connectivity hurdles.
  • You will proactively simulate network impairments (latency, jitter, packet loss) and use voice quality metrics (MOS) to ensure the system remains resilient and high-performing under sub-optimal conditions.
  • You will drive quality improvements within an Agile environment, participating in architectural reviews and brainstorming sessions to advocate for testability and system stability.
  • You will mentor the team and improve QA processes, sharing your expertise in troubleshooting stateful, event-driven systems and helping to refine estimation and testing methodologies.
  • You will maintain technical documentation and RCA (Root Cause Analysis) reports, ensuring that complex "hard-to-reproduce" bugs are well-documented and that the team learns from every critical leak.

Requirements:

  • 5+ years of software testing experience, with at least 2+ years in VoIP / Voice / real-time communication systems.
  • Strong hands-on understanding of SIP protocol (call flows, registrations, INVITE flows, SDP, RTP).
  • Practical experience analyzing SIP/RTP traffic.
  • Experience testing call center / CCaaS systems (IVR flows; ACD / call routing logic; Call recording; Agent states & call lifecycle).
  • Familiarity with WebRTC technologies and real-time communication challenges.
  • Deep understanding of voice quality metrics (latency, jitter, packet loss, echo, MOS).
  • Solid knowledge of TCP/IP networking, NAT, firewalls, ports, STUN/TURN.
  • Experience working in Linux environments and reading server logs.
  • Basic scripting skills in Python / JS / TS for test tooling and log analysis.
  • Experience with REST API testing (Postman, curl, or similar).
  • Understanding of RTP media flow vs SIP signaling.
  • Ability to debug one-way audio, no audio, delayed media, early media.
  • Experience testing systems that depend on timing, network conditions, and concurrency.
  • Understanding how telephony behaves differently from web applications (stateful, event-driven, race conditions).
  • Nice to have: Experience with test automation using Playwright or similar.
  • Nice to have: Experience with API automation frameworks (pytest, REST Assured, etc.).
  • Nice to have: Familiarity with performance / load tools: (k6, JMeter, Locust).
  • Nice to have: Experience simulating SIP traffic using SIPp.
  • Nice to have: Experience working with PBX / SBC / softswitches (Asterisk, FreeSWITCH, Zoiper, etc.).
  • Nice to have: Experience testing under network impairment (packet loss / delay simulation).

Benefits:

  • Your Wellness: Access to mental health programs, comprehensive medical insurance, and a sports card.
  • Your Happiness: Enjoy the company of cool teammates, a friendly atmosphere, a strong mentorship, and a variety of bonuses & corporate gifts.
  • Your Development: Benefit from free educational events & courses, and English classes with native speakers.
  • Your Career: Focus on your professional development in a supportive environment.
  • Work-Life Balance: Choose your working format - remote, office-based, or hybrid and engage in team-building activities.