Senior Full-stack Test Engineer

We are looking for a Senior Full-stack Test Engineer to take end-to-end ownership of quality for a System Integration Testing (SIT) project, combining strong manual testing depth with hands-on test automation.

This is an SIT role, not a UAT role. You will validate how multiple systems behave together — verifying business flows end to end, the impact of a change on upstream and downstream systems, and the contracts between services — rather than simply confirming acceptance criteria from a user's seat. You will drive the full test lifecycle for your primary project (test plan → test design → execution → sign-off), and at the same time keep an overview of 1–2 additional projects so you can advise their testing teams and step in when delivery is at risk.

The role suits someone with very high ownership and a proactive mindset: someone who chases requirements before they are handed over, raises integration risks early, and is comfortable being the quality decision-maker for their project.

Key Responsibilities

Project ownership

• Own the complete test lifecycle for one project: test strategy and test plan, test case design, test data preparation, execution, defect management, reporting, and formal sign-off.
• Maintain an overall view of 1–2 additional projects: understand their requirements and integration landscape, advise and unblock their testing teams, and support hands-on execution when a project is critical or at risk (100% execution on those projects is not expected).
• Participate in sprint planning and work closely with the Scrum team (developers, BAs, customer service, operations) to analyze requirements and provide test recommendations for feature, smoke, and regression testing.
• Act as the quality point of contact for your project — proactively raise risks, gaps, and integration dependencies rather than waiting for them to be assigned.
• Mentor and guide junior members of the test automation team, sharing best practices and knowledge.

System Integration Testing scope

• Non-Functional testing — design and execute unhappy paths, and negative scenarios across integrated systems, downtime and feature flags combination matrix testing across multiple channels of platform, DB testing. 
• BC & FC testing — assess and cover the impact of a change on the systems before and after it in the business flow, so integration side effects are caught rather than discovered in production.
• API testing — produce dedicated API test cases (not derived only from UI scenarios), and design scenario matrices that combine API response statuses, error conditions, and data variations to achieve meaningful coverage.
• Regression testing — plan and execute regression cycles manually, as required by the project; keep the regression suite current as the integrated systems evolve.
• Apply appropriate test techniques throughout: requirement analysis, risk-based testing, black-box techniques, exploratory testing, and non-UI testing.

Test automation

• Address test automation needs in a methodical, detail-oriented manner, using strong analytical and problem-solving skills.
• Automate functional, regression, and/or performance acceptance tests where automation adds value alongside the required manual coverage.
• Take responsibility for growing end-to-end automated test coverage and for keeping the automation suite stable and maintainable.

General Requirements:  

• Around 6+ years of experience in both manual & automation testing (flexible depending on how quickly you learn and grow technically) and encompassing API, UI, and Mobile platforms.
• Proven ability to run a project as the main tester, from test planning through to sign-off.
• Hands-on experience leading test teams and managing sprint-based manual and automation testing tasks.
• Strong ownership and a highly proactive working style — self-directed in seeking out requirements, risks, and stakeholders.
• Able to self-learn and quickly adapt to new technologies, systems, and domains.
• Familiar with Agile development methodologies.
• Able to perform under high pressure and handle parallel workstreams across projects.
• At least intermediate English communication skills.

Technical Requirements

• Strong experience testing APIs and web applications, including integration between multiple systems and services.
• Strong manual testing skills: requirement analysis, test strategy, test approach, test plan, and test design techniques (black box, risk-based, exploratory, non-UI testing).
• Proficiency in coding with JavaScript or TypeScript; proficiency in additional programming languages is highly regarded.
• Experience in automation testing using frameworks such as Katalon, Selenium, Playwright, Cypress, or similar.
• Experience with BDD frameworks (e.g., Cucumber, SpecFlow) to drive collaborative test case design and automation.
• Experience with tools such as Postman, Git, and IntelliJ IDEA.

Nice to have:

• Proficient daily use of AI coding tools (Copilot, Cursor, Claude Code) across the full SDLC
• Able to decompose complex tasks, provide effective context, and apply chain-of-thought and multi-step prompting workflows
• Experience with agentic workflows and AI-driven development frameworks
• Hands-on experience integrating AI tools with other systems via MCP (Model Context Protocol) or equivalent
• Awareness of emerging AI tools and willingness to evaluate and adopt new capabilities. 

Perks You'll Enjoy 

• Working in one of the Best Places to Work in Vietnam
• Building large-scale & global software products
• Working & growing with Passionate & Talented Team
• Diverse careers opportunities with Software Services, Software Product Development, IT Solutions & Consulting
• Attractive Salary and Benefits
• One performance appraisals every year and performance bonus
• Onsite opportunities: short-term and long-term assignments in North American (U.S, Canada), Europe, Asia.
• Flexible working time
• Various training on hot-trend technologies, best practices and soft skills
• Premium healthcare insurance for you and your loved ones
• Company trip, big annual year-end party every year, team building, etc.
• Fitness & sport activities: football, tennis, table-tennis, badminton, yoga, swimming…
• Joining community development activities: 1% Pledge, charity every quarter, blood donation, public seminars, career orientation talks,…
• Free in-house entertainment facilities (foosball, ping pong, gym…), coffee, and snack (instant noodles, cookies, candies…)

And much more, join us and let yourself explore other fantastic things!

KMS Technology is a strategic engineering company helping businesses turn bold ideas into high-impact solutions—faster. Founded in 2009 as a U.S.-based services company, we’ve grown into a global organization with locations in the US, Vietnam, Mexico and Poland. KMS is trusted globally for the quality of our engineering and consulting services. We bring deep expertise in product development and quality assurance, Data & AI-native engineering, and delivery excellence to every engagement. Our mission is to help customers build what’s next—accelerating innovation, crafting brilliant solutions, and creating  real-world impact. At KMS, we believe sustainable growth is built on the success of our clients and employees, and in making a lasting contribution to our communities.

More about KMS Technology:

Website: https://kms-technology.com 

LinkedIn: https://www.linkedin.com/company/kms-technology