Senior QA Backend Engineer

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We are seeking a highly analytical Senior QA Backend Engineer to orchestrate the validation of complex, multi-service architectures and event-driven data flows. In this position, you will heavily focus on backend testing—analyzing system logs, tracing service-to-service communication, and validating backend message handling across modern cloud infrastructure. Operating within an Agile environment, you will bridge communication gaps between multiple development teams, identify critical system paths, and ensure end-to-end product stability.

Details

Seniority: Senior (5+ years of software testing experience).

Allocation: Full-time (1 FTE).

Rate: 65-80 pln/h B2B

Start Date: ASAP.

Languages: English at a C1 level (essential for cross-team coordination).

Work Model & Location: Hybrid. Weekly on-site presence required on Thursdays at the client's office in Warsaw (Mokotów), plus mandatory on-site attendance for periodic PI Planning sessions.

Responsibilities

• Backend & Microservices Validation: Deep-dive into testing distributed microservice architectures, verifying that data flows, async states, and transactions resolve correctly across isolated components.

• Event-Driven & Integration Testing: Map and validate messaging architectures, specifically focusing on event queues, data ingestion routing, and message pub/sub lifecycles.

• Log & Trace Analysis: Proactively parse server-side logs, monitor internal API gateways, and evaluate database persistence to uncover anomalies before they reach production.

• Test Orchestration: Strategy, plan, and execute rigorous integration, system, usability, and E2E testing suites, while guiding cross-functional teams through complex User Acceptance Testing (UAT) gates.

• Cross-Squad Alignment: Drive alignment and foster communication between distinct development squads to pinpoint high-risk areas, eliminate technical silos, and improve platform reliability.

Requirements

• Core QA Competencies

  • 5+ years of verified commercial experience in end-to-end software testing with strong analytical test design capabilities.

  • Solid architectural understanding of web and mobile application structures.

  • High proficiency with test and defect management tooling (e.g., Jira, Xray, TestRail, YouTrack).

  • Experienced operating within agile software development lifecycles (Scrum/Kanban).

• Backend & Systems Stack

  • Strong experience tracking asynchronous integrations via AWS SNS/SQS or similar queue infrastructures.

  • Hands-on command over API testing toolsets (Postman, Swagger, etc.).

  • Proficient with SQL databases (writing queries, validating schema states, and isolating data anomalies).

• Nice to Have (Pluses)

  • Domain experience inside Card Payments or Card Management Systems (Fintech/Banking).

  • Hands-on familiarity with test automation structures for mobile or web surfaces.

  • Deep architectural understanding of REST API standards, HTTP status protocols, and API contract testing.

  • Professional QA certifications (ISTQB Foundation and/or ISTQB Advanced Level Test Analyst).