🤖 15+ AI Agents working for you. Find jobs, score and update resumes, cover letter, interview questions, missing keywords, and lots more.
Cookies & analytics consent
We serve candidates globally, so we only activate Google Tag Manager and other analytics after you opt in. This keeps us aligned with GDPR/UK DPA, ePrivacy, LGPD, and similar rules. Essential features still run without analytics cookies.
Read how we use data in our Privacy Policy and Terms of Service.
🤖 15+ AI Agents working for you. Find jobs, score and update resumes, cover letter, interview questions, missing keywords, and lots more.
MMDSmart • Serbia
Role & seniority: QA Engineer (senior level) focused on VoIP/real-time communications; 5+ years testing, 2+ years in VoIP.
Stack/tools: VoIP/telecom testing (SIP protocol, SIP/RTP traffic); WebRTC; PCAPs and server logs; Linux; TCP/IP networking; NAT, firewalls, STUN/TURN; Python/JavaScript/TypeScript for tooling; REST API testing (Postman/curl).
Analyze requirements and specs, challenge architecture to prevent production issues; design and execute end-to-end test strategies for WebRTC, IVR, ACD routing, and call recording.
Act as “Voice System Investigator” analyzing call flows and media to identify root causes in signaling and audio; simulate network impairments and measure MOS.
Improve QA in Agile, mentor team, document RCAs, and contribute to testability, estimation, and testing methodologies; maintain technical docs.
5+ years software testing; 2+ years in VoIP/real-time systems
Deep SIP/RTP knowledge; analyze SIP/RTP traffic
WebRTC familiarity; understanding of voice quality metrics (latency, jitter, packet loss, echo, MOS)
Networking basics (TCP/IP, NAT, firewalls, ports; STUN/TURN)
Linux experience and server log reading; basic scripting (Python/JS/TS)
REST API testing experience
Test automation (Playwright) and API automation frameworks (pytest, REST Assured)
Performance/load tools (k6, JMeter, Locust)
SIP traffic simulation (SIPp); PBX/SBC/softswi
Would you like to build a career in a leading multinational IT company? We are looking for a QA engineer who behaves more like a voice system investigator than a checklist tester to join our team. Since 2007, MMDSmart has been a leading supplier in cloud communications, delivering game-changing IT products to businesses in over 100 countries. Our success is fueled by the inspiration and innovative ideas of our team members, encouraging their growth and impacting our Messaging and Voice solutions. These empower our clients to communicate more effectively with their customers. Don’t miss this chance to excel in a rapidly expanding tech company, where your potential and ambitions are not just recognized but celebrated.
What will you do at MMDSmart? 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.
Familiarity with performance / load tools: (k6, JMeter, Locust) Experience simulating SIP traffic using SIPp Experience working with PBX / SBC / softswitches (Asterisk, FreeSWITCH, Zoiper, etc.) Experience testing under network impairment (packet loss / delay simulation) Why do talents choose and stay at MMDSmart?
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. Think this role's got your name on it? Go ahead and apply, we'd love to see what you've got! Equal-Opportunity Employment We are an equal opportunity employer committed to creating a diverse and inclusive work environment. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status. *Medical Insurance and Sport Card perks are available for employees located in Bulgaria.