The team is developing the following projects:

SBC - SIP Session Border Controller, a solution located at the edge between the Internet and the intranet, the goal of the project is to provide a reliable entry point for all client devices and applications;

• Network Load Balancing Router

• Internet to intranet edge solution, a distributed L3 / L4 router to balance traffic from client devices to the SBC. The solution is based on eBPF/XDP technology.

• Media Resource Broker

• Component of the system that manages media resources and makes a brokering function between demanders.

Media Engine - a realtime network audio converter. The solution is based on RTP and gRPC.

**This role requires on-site presence at our office 4 days a week to support effective collaboration and teamwork.You will be required to:

• Participate in the development of high load server systems running 24/7;

• Analyze requirements, develop test strategy and test cases design;

• Document defects, find ways to reproduce and verify fixes;

• Support the product being created throughout the release cycle;

• Write and run test cases;

• Deploy, update and maintain test environments;

• Analyze software logs for presence of errors

We expect:

• 5+ years' experience in server software testing.

• Understanding of QA as a quality assurance process, knowledge of software testing processes and methodologies.

• Skills in working with functional and nonfunctional requirements.

• Experience of working with Linux distributions.

• Experience of software test automation (Go/Python and others).

• English level at least Pre-Intermediate.

• Knowledge of GitLab CI/CD and Kubernetes.

• Practical experience in network troubleshooting (TCP/IP, UDP, HTTP/S, DNS; packet analysis with Wireshark, connectivity checks, port debugging)

Will be an advantage:

• Experience in VoIP telephony (working with SIP protocol, network traffic analysis)

• Experience in distributed systems testing

• Experience in SBC or SIP-proxy testing

• Understanding of VoIP SIP/SDP, RTP protocols

• Knowledge of HTTP protocol

• Knowledge of Kibana

What we offer:

• Well-coordinated professional team.

• Cutting edge technologies, interesting and challenging tasks, dynamic project, great opportunities for self-realization, professional and career growth.

• Additional Health and Life Insurance Package.

• Employee Assistance Program.

• 25 vacation days.

• 102,26 EUR/200 BGN Digital Food Vouchers.

• 61, 36 EUR/120 BGN Gross as part of the salary for Working Expenses Allowance.

Say hello to opportunities.

If you’re looking to be part of what’s next in communication, you’re in the right place.

At Ring Central, we believe the best customer experiences happen when humans and AI work together. Our agentic voice AI portfolio—AIR, AVA, and ACE—brings together automation, assistance, and insights across the entire conversation lifecycle. The result? More seamless, intelligent experiences for businesses everywhere.

With $2.5B+ in ARR and $250M invested in R&D annually, we’re building the future of AI-powered business communications.

About Ring Central

Ring Central is a global leader in agentic voice AI–powered business communications, delivering an integrated platform for business phone, SMS, contact center, workforce engagement management, video collaboration, and messaging. As the communications layer connecting businesses and customers, Ring Central is the front door of business communication and is in the advantageous position to apply AI at every phase of the conversation journey — before, during, and after each interaction. Our agentic AI portfolio includes autonomous voice-first AI agents that automate calls, assist in the moment, and analyze every interaction – enabling businesses to work smarter, respond faster, and connect more meaningfully with their customers.
Ring Central is an equal opportunity employer that truly values diversity. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.