About the Role:
We’re looking for a Backend Engineer to contribute to a next-generation security initiative. You’ll be part of a small, highly technical team working on novel approaches to secure systems - with a focus on cryptography, automation, and AI-powered analysis. You’ll work closely with senior engineers and contribute hands-on to the codebase across the stack. This role involves hands-on development, learning opportunities, and collaboration across engineering, product, and design.

Day to Day:

• Contribute to the design, development, and delivery of features across the product
• Write clean, maintainable code for back-end systems deployed in AWS or GCP
• Collaborate with AI and cryptography specialists
• Work with the product manager to understand requirements and help the team plan architecture, data flows, API specs, and testing strategies
• Follow established engineering practices and participate in team discussions around process and quality
• Participate in customer-driven development and iterate based on feedback
• Write automated tests for load, performance, and error handling

What you bring to the table:

• 3+ years of hands-on software engineering experience for backend development
• Excellent TypeScript and Node.js coding experience
• AWS experience in containers (EKS, ECS) and serverless systems
• Relational, key/value, and graph datastore experience with schema management
• API design, data modeling, secure service development, database systems
• Has a focus on quality code, error handling, and high availability
• A thoughtful, pragmatic approach to solving technical problems in a fast-paced environment
• At least upper-intermediate level of spoken and written English

Extra Credit:

• Versed in Python coding and environments
• Experience with GCP systems
• Experience with applied cryptography, especially key management, TLS, or post-quantum algorithms
• Familiarity with agent-based architectures or systems that scan and orchestrate actions across distributed environments
• Knowledge of AI/ML systems, particularly LLM integration or agent-style reasoning patterns
• Experience managing LLM agents to increase both speed and quality of code generation and tests
• Exposure to security tools, vulnerability detection platforms, or compliance automation
• Prior experience working on developer-facing or infrastructure-heavy products

About the Role:

We’re looking for an experienced QA Automation Engineer (Mobile/Android) to take the lead in ensuring our global security products meet the highest bars of reliability. In this role, you won’t just run tests; you’ll architect and scale automation solutions for our VPN portfolio (HotspotShield, Betternet) and our flagship antivirus (UltraAV). We are agile, work quickly, and focus on outcomes. We trust our team to build the best solution to help us scale for the future.

Day to Day:

• Architect and evolve our Android automation framework (Espresso/Kakao-Cup) to support a growing portfolio of security products.
• Design sophisticated testing strategies for VPN-specific challenges, including network-dependent flows and testing under unstable or switching connection states.
• Work closely with developers and other QAs to troubleshoot and resolve issues, offering detailed bug reports.
• Uphold QA best practices and contribute to driving the QA strategy.
• Continuously explore new testing tools and methodologies to enhance the QA process.

What you bring to the table:

• At least 3 years of experience in automating UI tests for Android apps written in Kotlin
• Strong hands-on expertise with Espresso and Kakao-Cup, with the ability to test screens built in both Jetpack Compose and classic XML.
• Experience with Robolectric and Mockito for test infrastructure and mocking dependencies.
• You’re comfortable building and maintaining pipelines in CircleCI and using Bash/sh scripting for automation and result processing.
• Experience sharding and parallelizing tests using Flank, and configuring device matrices within Firebase Test Lab or similar emulators.
• An understanding of the specific challenges of testing VPN apps, such as network-dependent flows and handling connection-state flakiness.
• At least upper-intermediate level of spoken and written English

It would be great if you also had:

• Experience maintaining UI test suites across multiple apps in both mono- and multi-repo setups.
• High level of comfort with ADB, log analysis, and a working understanding of the Android build process via Gradle (Kotlin DSL).
• Experience testing A/B frameworks, including covering feature-flagged flows and variant-dependent UI.
• Familiarity with testing Google Play Billing integrations (subscriptions, purchase flows, and edge cases).

Why Join Us?

• Professional Growth: Enhance your skills by collaborating closely with talented engineers and architects.
• Meaningful Impact: Help create software that protects millions of users from cybersecurity threats.
• Supportive Environment: Join a team dedicated to innovation, mentorship, and continuous learning.

The role

Fraud prevention is an ever-evolving puzzle, making it one of the most rewarding and impactful areas in fintech. At GoCardless, our Fraud Prevention team develops the intelligent systems that protect our platform, our merchants, and their customers.

As a Senior Data Scientist, you will guide the design and delivery of models that operate in real time across our global payment network. You’ll work at the intersection of machine learning, graph-based detection, and behavioural modelling to stay ahead of changing patterns turning research into production systems that make a tangible difference in the fight against financial crime.

You’ll collaborate closely with Engineers, Fraud Analysts, and Product Managers to help shape the technical roadmap as we expand into new markets. Our stack is centred around Google Cloud Platform and Vertex AI, using Python, SQL, and BigQuery to build and support high-performance models at scale.

What you'll do

• Contribute to the full model lifecycle, from initial discovery and feature engineering through to production, experimentation, and continuous monitoring.
• Design and refine real-time ML systems that reduce false positives and ensure a smooth, secure experience for legitimate customers.
• Foster a responsive feedback loop, adapting models as patterns evolve to ensure our defences remain robust and effective.
• Help shape the technical direction of fraud prevention ML at GoCardless, exploring new approaches as we grow globally.
• Support the team’s growth through technical mentorship, knowledge sharing, and a commitment to high-quality code.

What excites you

• Solving complex, dynamic problems: Developing systems that can adapt and respond to changing environments.
• End-to-end ownership: Seeing a project through from a conceptual business need to a live, impactful solution.
• Strategic influence: Contributing to the ML roadmap and helping determine what we build next, rather than just how we build it.
• Holistic Data Science: Engaging in deep-dive analysis, prototyping, and live experimentation.
• Modern Infrastructure: Building production-grade models on GCP and Vertex AI, with the flexibility to explore advanced architectures.

What excites us

• You hold a degree (or PhD) in a STEM discipline, or bring equivalent depth through commercial experience.

• You have hands-on experience with modelling approaches such as deep learning, graph-based methods, or sequence models. While fintech experience is great, we value transferable skills from fields like cybersecurity or risk modelling.
• You have a track record of deploying models in production that create measurable value.
• You can translate complex ML concepts into clear, practical solutions for stakeholders across the business.
• You enjoy writing clean code and helping the team thrive through thoughtful reviews and shared learning.

Base salary range: €64,000 - €96,000

Base salary ranges are based on role, job level, location, and market data.  Please note that whilst we strive to offer competitive compensation, our approach is to pay between the minimum and the mid-point of the pay range until performance can be assessed in role. Offers will take into account level of experience, interview assessment, budgets and parity between you and fellow employees at GoCardless doing similar work.

The role

As a Product Security Engineer, you will enable development teams to take ownership of the security and privacy of their product by collaborating to set requirements and standards, performing design reviews and vulnerability assessments, and helping build security controls. You will also work closely with the dedicated Security Operations and Security Engineering teams. 

You will be someone who has experience securing a cloud-native environment, and, in particular, in embedding security and privacy standards in engineering functions. You should also be comfortable automating security and privacy engineering and performing various security assessments.

What excites you 

• Developing high-quality code for extensive tasks, showcasing proficiency in leading systems and architecture design independently. 
• Leading the design and documentation processes for complex tasks, breaking them down into manageable segments for team collaboration while also handling the most challenging portions.
• Contributing significantly to the company-wide systems architecture, impacting the organisation's technological landscape.
• Providing guidance to developers and architects on secure coding methodologies, architectural design, and security best practices, fostering a culture of excellence within the team.
• Overseeing the vulnerability management program, conducting routine assessments, prioritising resolutions, and tracking progress towards securing systems.
• Demonstrating advanced proficiency in security testing, ensuring comprehensive evaluations of system, application, and network security postures.
• Creating and maintaining robust security policies, procedures, and guidelines for effective programme management.

What excites us  

• Experience in cloud-based application and infrastructure security - especially, DevSecOps
• Background in threat modelling and security architecture/secure design
• Awareness of or exposure to security and privacy standards, such as ISO27001, SOC1, CyberEssentials, GDPR, or similar
• Nice to have: Cybersecurity certifications, such as CISSP, CEH, Professional Cloud Security Engineer, or similar
• Technical experience in working with cloud computing providers such as GCP or AWS
• Technical leadership qualities -  setting direction alongside the managers and supporting the security team in technical development. 

Base salary range: €4,133 to €6,200 gross monthly

Base salary ranges are based on role, job level, location, and market data.  Please note that whilst we strive to offer competitive compensation, our approach is to pay between the minimum and the mid-point of the pay range until performance can be assessed in role. Offers will take into account level of experience, interview assessment, budgets and parity between you and fellow employees at GoCardless doing similar work.