Senior Software Engineer (SDET)

Mastercard; Leixlip; On-site; EUR 70,000 - 110,000; Full time

Job summary

Mastercard Ireland seeks a Senior Software Development Engineer in Test (SDET) to drive automation, test strategy, and quality across AI-enabled workflows and APIs. You will lead scalable automation, partner with engineers and data teams, and own testing outcomes from design through production.

Required skills include Java or Python, Playwright/Selenium/Cypress, and experience with CI/CD pipelines in distributed systems. Join a team delivering reliable, secure payments platforms.

Qualifications

• Strong experience in software test automation and framework design.
• Experience testing distributed systems, APIs, and AI-enabled applications.
• Knowledge of Agile, CI/CD, and shift-left testing.
• Ability to validate agentic workflows and non-deterministic systems.

Responsibilities

• Own end‑to‑end quality for agentic applications, AI-powered workflows, and platform services.
• Design, develop, and maintain robust UI/API automation frameworks.
• Define test strategies for AI/LLM-based systems and ensure release quality.
• Build test data and drive root cause analysis through to resolution.
• Collaborate with engineers, product managers, and data/AI teams to embed quality.
• Mentor teammates on automation and quality best practices.

Skills

Java

Python

Automation

Test Frameworks

Playwright

Selenium

Cypress

REST Assured

Tools

Playwright

Selenium

Cypress

REST Assured

CI/CD

Job description

Our Purpose

Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we’re helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential.

Title and Summary

Senior Software Engineer (SDET)

Senior Software Engineer in Test (SDET)

Overview:

Who is Mastercard?

Mastercard is a global technology company in the payments industry. Our mission is to connect and power an inclusive, digital economy that benefits everyone, everywhere by making transactions safe, simple, smart, and accessible. Using secure data and networks, partnerships and passion, our innovations and solutions help individuals, financial institutions, governments, and businesses realise their greatest potential.

Our decency quotient, or DQ, drives our culture and everything we do inside and outside of our company. With connections across more than 210 countries and territories, we are building a sustainable world that unlocks priceless possibilities for all.

Role Overview

The CNPF Data & AI organisation is looking for a Senior Software Engineer in Test (SDET) to help build and assure the next generation of intelligent, agentic products and platforms. This is a hands‑on senior engineering role for someone who combines deep automation expertise with strong software engineering fundamentals and practical experience testing AI‑powered and agent‑based systems in production‑grade environments.

This role is ideal for a builder who enjoys solving complex quality challenges, designing scalable automation strategies, and raising the engineering bar across teams. We are particularly interested in candidates who can apply innovative thinking, strong ownership, and modern quality engineering practices to validate agentic applications, LLM‑powered workflows, APIs, user journeys, and end‑to‑end platform reliability.

We are seeking a talented Senior Software Development Engineer in Test (SDET) to define and implement an effective automation and quality strategy within an Agile team. This role will validate application functionality, resilience, and business outcomes using modern testing methodologies, strong engineering discipline, and best practices in continuous integration and delivery.

Role:

• Own end-to-end quality engineering for agentic applications, intelligent workflows, APIs, user interfaces, and supporting platform services.
• Design, develop, and maintain robust automation frameworks for UI, API, integration, regression, and system-level testing.
• Define test strategies for AI and agent-based systems, including workflow validation, response quality, tool usage, guardrails, reliability, and failure handling.
• Build automated quality gates for CI/CD pipelines and ensure high‑confidence releases through continuous testing.
• Partner closely with software engineers, product managers, architects, and data/AI teams to ensure quality is built in from design through production.
• Create meaningful test data, validate edge cases, identify defects early, and drive root cause analysis through to resolution.
• Evaluate non‑functional characteristics such as performance, reliability, observability, resilience, and scalability.
• Contribute innovative ideas that improve testability, developer productivity, release confidence, and engineering effectiveness.
• Demonstrate strong ownership by proactively identifying gaps, driving improvements, and mentoring team members on automation and quality best practices.

About You

• Strong experience in software test automation, automation framework design, and code quality practices.
• Proven ability to test modern distributed systems, APIs, event‑driven architectures, and user‑facing applications.
• Experience validating AI‑enabled or agentic applications, including prompt/workflow validation, output quality assessment, and scenario‑based testing.
• Strong understanding of Agile development, shift‑left testing, continuous integration, and continuous delivery.
• Comfortable working across ambiguity and applying innovative thinking to solve new and evolving quality challenges.
• Strong communication, collaboration, and stakeholder management skills, with a bias for action and accountability.

Technical Skills

• Strong programming skills in Java, Python, or similar languages used for automation and test engineering.
• Hands‑on experience with API and UI automation frameworks such as Playwright, Selenium, Cypress, REST Assured, or equivalent.
• Experience integrating automated tests into CI/CD pipelines and quality gates.
• Understanding of test approaches for LLMs, retrieval workflows, agent orchestration, and non‑deterministic systems is highly desirable.
• Familiarity with observability, logging, test data management, performance testing, and service virtualization is a plus.

Leadership & Mindset

• Innovative thinker who challenges conventional approaches and introduces better ways to assure quality at scale.
• Strong sense of ownership, accountability, and follow‑through from test strategy through delivery outcomes.
• Able to influence quality culture across teams and mentor others in modern automation and engineering excellence.

Corporate Security Responsibility

• Abide by Mastercard’s security policies and practices;

• Ensure the confidentiality and integrity of the information being accessed;

• Report any suspected information security violation or breach, and

• Complete all periodic mandatory security trainings in accordance with Mastercard’s guidelines.