As an emerging leader in the $10B+ communications API market, we empower global brands to connect better with their customers, employees, and partners through transformative communications experiences. Vonage API solutions empower organisations to build their custom omnichannel communications structure, allowing them to reach and engage customers on their preferred schedule and channel, including voice, video, and messaging. Think of a rideshare service instantly connecting with customers, hospital staff conducting remote monitoring, customers verifying their identity before completing a purchase, AI virtual agents servicing customers around the clock, and much more.

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Why this role matters

As a Senior Software Development Engineer in Test (SDET IV) on the Voice Test Engineering team, you embed quality, reliability, and observability into every stage of our voice platform's software development lifecycle. You partner closely with engineering teams to design, build, and ship robust, testable voice infrastructure, and you architect, develop, and maintain the automated test frameworks, suites, and tooling that power continuous integration, delivery, and deployment across Vonage's globally distributed voice platform.

Your work ensures reliability at scale across SIP signaling, media processing, emergency calling, and voice API services, covering functional, integration, performance, chaos, and regression testing, while accelerating developer productivity and reducing defect escape in production. You will be a key technical leader within our Python-based voice test automation framework, driving its evolution and expanding its coverage across SIP proxy APIs, inbound/outbound call flows, Asterisk, FreeSWITCH, Kamailio, and Kubernetes-hosted voice services across six global AWS regions.

As a senior technical leader, you will influence architectural decisions within the test framework, introduce best-in-class testability patterns, mentor engineers in automation and quality engineering practices, and drive continuous improvement across CI/CD pipelines. Your impact will be measured not only in test coverage and defect reduction, but in the platform reliability, operational confidence, and engineering culture you help create.

If this sounds like you, continue reading below...

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Your key responsibilities

• Influence architecture and design reviews with a focus on testability, SIP call flow coverage, performance, and the long-term automation strategy for the voice platform
• Architect and evolve our voice test automation framework, including API client layers, Pydantic-typed service abstractions, pytest fixture hierarchies, and Jenkins seed-based CI orchestration, to support continuous onboarding of new voice features and services
• Build and maintain scalable CI/CD-aligned test suites (smoke, regression, performance, chaos, non-functional) across all supported AWS regions; assess feature impact, close coverage gaps, and own quality gates for production deployments
• Author and own SIPp scenario XML files for complex SIP call simulations: inbound/outbound routing, SIP proxy API validation, emergency calling, domain auth (ACL/dauth), and multi-region failover scenarios
• Lead chaos and non-functional test strategy, designing fault injection scenarios (chaos-mesh, AWS FIS) targeting Asterisk, FreeSWITCH, Couchbase, Redis, PSLB, and INPS to validate platform resilience and failover behavior
• Drive quality operations: track, triage, and escalate defects and enhancements in JIRA; communicate risks, required test hooks, and release readiness to engineering and product stakeholders
• Mentor SDET III engineers in SIP testing, Python framework design, pytest best practices, and Kubernetes-based test environment management

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What you'll bring

• Self-motivation, creativity, and proactiveness to work successfully in a fast-paced environment spanning diverse voice technologies, cloud infrastructure, and distributed architectures
• Deep proficiency in troubleshooting and root cause analysis of SIP call failures, media processing defects, and distributed system issues, using logs, traces, VoIPMonitor CDRs, and Wireshark packet captures
• Ability to operate in a dynamic, team-oriented environment and meet tight release deadlines across multiple global regions
• Excellent verbal and written communication skills; able to translate complex SIP/voice failure modes into clear, actionable insights for engineering and product stakeholders

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Required

• B.S./B.A. degree in Engineering, Computer Science, or related discipline; or technical certification and/or equivalent experience
• Expert-level Python 3 proficiency, with deep experience in pytest (fixtures, markers, parametrize, conftest scoping, session/function/class scope management) and Pydantic models for typed request/response validation
• Deep SIP protocol expertise: INVITE/BYE/ACK/CANCEL flows, SDP negotiation, SIP headers, RTP/SRTP media paths, CDR validation, and SIP-level debugging with tools such as SIPp, Wireshark, or VoIPMonitor
• Proven experience designing and implementing automated test frameworks and suites (smoke, regression, performance, chaos) that measurably reduce defect escape in production
• Hands-on experience with Asterisk and/or FreeSWITCH as components under test in a SIP/VoIP environment
• Strong Kubernetes experience: EKS cluster access (kubectl, Helm, ArgoCD), namespace-level debugging, pod log inspection, and test environment management via Teleport or equivalent
• Solid AWS experience: EC2, S3, SSM Parameter Store, EKS, including programmatic interaction from test code

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Experience we consider a plus

• Experience with Couchbase or other NoSQL document stores in a testing or chaos engineering context
• Experience with chaos testing frameworks (chaos-mesh, AWS FIS) for fault injection against Kubernetes-hosted voice services
• Knowledge of Kamailio or other SIP proxy/load balancer technologies
• Familiarity with GitHub Copilot (Agent Mode) or other AI-assisted tools integrated into test development workflows

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How you'll benefit

There are many benefits to working at Vonage, including exciting work, career advancement opportunities, and a collaborative work environment. In addition, we offer the following local benefits for Poland:

 

• Medical Insurance (Allianz)
• Life Insurance (Uniqa)
• Glasses Reimbursement
• Kafeteria (My Benefit)
• Discretionary Time Off (DTO)
• Volunteer Time (VTO)
• Ericsson Care Line

Additional benefits and perks will be shared and discussed with you by the recruiter during the interview process.

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