About this role
Position Summary
We're looking for a strong Senior QA Engineer with leadership experience — someone who can not only design and maintain automated testing for backend and data-heavy systems in the blockchain domain, but also shape the team's technical vision, influence architectural decisions, and own product quality on a long-term basis.
This is a fully remote role, and we welcome applications from anywhere in Europe.
Design, develop, and maintain automated tests for backend/API and frontend services and data-processing systems in the blockchain domain, including API, integration, contract, and data validation coverage
Create reliable test coverage for edge cases such as missing data, delayed data, and incorrect calculations
Analyze failed tests and production-like issues using logs, metrics, monitoring dashboards, API responses
Conduct code reviews
Pioneer new approaches, architectures, or frameworks that drive the business forward
Focus on long-term systemic planning, making high-level trade-offs across projects, and establishing technical vision
Prioritize testing efforts based on business needs, project risks, and delivery timelines
Identify process improvement opportunities and implement QA best practices
Evaluate and drive adoption of AI tools for QA and development workflows (e.g., AI-assisted test generation, code review, automation frameworks)
Define best practices and guidelines for using AI tools within the QA process, and help the team integrate them effectively
Collaborate closely with developers, business stakeholders, and cross-functional teams to improve testability, observability, and reliability of services
Maintain test documentation, automation coverage notes, and clear defect reports
Required:
5+ years of AQA/SDET experience testing complex backend, API, data-heavy, or distributed systems
Deep understanding of SOLID principles and design patterns, hands-on experience applying them into test frameworks;
Solid SQL and PostgreSQL experience, including advanced queries, data validation, and investigation of data inconsistencies
Strong test design skills
Understanding of backend architecture, environment-based configuration, service health checks, and deployment validation
Strong Java programming skills for test automation
Hands-on experience with test automation tools and frameworks (e.g., Playwright, Postman, REST-assured or similar for API testing; Allure for reporting)
Experience of working with version control systems (GIT);
Experience working in Scrum or another Agile delivery process
Hands-on experience with AI-assisted development tools such as Cursor and Claude, including creating custom skills, agents, and rules to support QA/development workflows
Hands-on experience with AI no-code tools and business process automation (e.g., n8n)
Proficiency in English
Would be a plus:
QA technical leadership experience
Experience in performance testing
Python knowledge
Tech stack:
Languages: Java (primary, for test automation); Python (nice to have, such as backend is written on this language)
Database: PostgreSQL
Test automation: Playwright, Postman or REST-assured (API testing), Allure (reporting)
CI/CD: GitHub Actions
AI & Automation Tooling: Cursor or Claude for AI-assisted development, n8n for workflow automation (e.g., Jira ticket automation, bug-report pipelines)
Project & Collaboration Tools: Jira, ClickHouse, Mintlify, Drata (compliance tooling), Spira (test case management), Tailscale
Locations
Kraków, Bucharest, Lisbon, Vilnius
Crystal is a globally distributed team of world-class blockchain analysts, award-winning mathematicians, and professional software developers with headquarters in London and Amsterdam.
We design an all-in-one blockchain analytics solution for regulators, financial services, and law enforcement.
Our crypto transaction monitoring and risk assessment software enables financial institutions to comply with global anti-money laundering regulations.
Law enforcement agencies and regulators use our technology and data to track the movement of cryptocurrencies in real-time to identify illicit fund flows and solve investigations.
Our platform, Crystal Expert, is available as a free online blockchain explorer, as SaaS, or API.
Founded in
2016
Co-workers
100+
Multiple locations
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