Be ready to go over:

• Ad Call Lifecycle – How an ad request travels from a publisher's page to the exchange and back.
• API Payload Validation – Verifying JSON and XML payloads for correctness and completeness.
• Latency and Performance Testing – Ensuring that API responses meet strict latency thresholds.
• Advanced concepts (less common) – Understanding OpenRTB protocols, header bidding mechanics, and cookie syncing processes.

Example scenarios:

• Inspecting an XML template to verify that the correct tracking pixels are fired during an ad impression.
• Designing a test suite to validate the behavior of an API when it receives malformed payloads.

Test Automation & Scripting

You will need to demonstrate your ability to write automated tests that are reliable, maintainable, and scalable.

Be ready to go over:

• Automation Best Practices – Writing clean, reusable code and avoiding flaky tests.
• Framework Familiarity – Understanding how to build and maintain tests using common frameworks like Selenium, Cypress, or Robot Framework.
• Integration Testing - Testing how different services interact with one another.

Example scenarios:

• Writing an automated script to test a user login flow or an API endpoint.
• Explaining how you would structure an automation suite to run as part of a continuous integration (CI/CD) pipeline.

As a QA Engineer at OpenX, your daily activities will center around ensuring the quality and stability of the programmatic marketplace. You will work closely with cross-functional teams to deliver high-quality software in a fast-paced environment.

• Designing and Executing Test Plans – You will analyze product requirements to create comprehensive test strategies covering functional, integration, regression, and performance testing.
• Developing Automated Test Suites – You will write and maintain automated test scripts to validate APIs, user interfaces, and backend data processing systems.
• Validating High-Volume Data – You will write complex SQL queries to verify the integrity and accuracy of transactional data and reporting systems.
• Collaborating with Engineering Teams – You will work alongside software developers and product managers to identify bugs early in the development lifecycle and ensure timely resolution.
• Investigating Production Issues – You will help triage and troubleshoot complex issues reported in production, working to identify root causes and prevent future occurrences.

To be competitive for the QA Engineer position at OpenX, you should possess a strong technical foundation and a collaborative mindset.

• Must-have skills – Strong proficiency in SQL and database validation techniques. Experience writing automated tests using languages like Python, Java, or JavaScript. Solid understanding of API testing tools and methodologies.
• Nice-to-have skills – Prior experience working in the programmatic advertising (adtech) industry. Familiarity with Robot Framework, Docker, and CI/CD pipelines. Experience testing big data technologies like Hadoop or Spark.

You should have a proven track record of testing complex, distributed systems and a passion for delivering high-quality software. Excellent communication skills are essential, as you will be collaborating with teams across different locations and time zones.

Q: How difficult is the technical interview for a QA Engineer at OpenX? A: The interview difficulty is generally rated as average to easy, provided you have a strong foundation in SQL and test automation. The questions are practical and focus on real-world scenarios rather than abstract algorithmic puzzles.

Q: Is prior adtech experience required for this role? A: While prior experience in programmatic advertising is a significant advantage, it is not strictly required. However, you should take the time to learn the basics of ad exchanges, ad calls, and programmatic bidding before your interviews.

Q: What is the typical timeline for the hiring process? A: The entire process, from the initial recruiter screen to a final decision, typically takes about three to four weeks. Communication is generally friendly and collaborative throughout the process.

Q: What automation frameworks does OpenX use? A: OpenX utilizes a variety of automation tools and frameworks, including Python-based libraries and keyword-driven frameworks like Robot Framework. Candidates are generally allowed to use their preferred scripting language during coding evaluations.

To maximize your chances of success during the OpenX interview process, keep these practical tips in mind:

• Master SQL Joins and Aggregations: Ensure you can comfortably write queries to analyze and validate complex data sets, as this is a heavily tested area.
• Understand the Basics of Programmatic Advertising: Spend time researching how ad exchanges work, what an ad call looks like, and how XML templates are used in ad delivery.
• Be Prepared for Framework-Specific Questions: If you are asked about a framework you do not know, focus on demonstrating your foundational testing principles rather than memorized syntax.

• Showcase Your Automation Mindset: When discussing past projects, emphasize how you used automation to improve efficiency, reduce manual testing effort, and increase test coverage.
• Follow Up Politely: If you experience delays in communication during the process, send a professional follow-up email to your recruiter to express your continued interest.

The QA Engineer role at OpenX offers an exciting opportunity to work on a highly complex, high-scale programmatic advertising platform. Your work will directly impact the performance and reliability of a system that processes billions of transactions daily, making this a challenging and rewarding position.

To prepare effectively, focus your efforts on mastering SQL, practicing API testing scenarios, and understanding the core mechanics of the adtech ecosystem. Approaching your interviews with a collaborative, problem-solving mindset will help you stand out as a strong candidate.

For more insights, real interview experiences, and comprehensive preparation resources, you can explore additional materials on Dataford to help you succeed in your upcoming interviews.

The salary data provided reflects typical compensation ranges for QA engineering professionals in the technology sector. When preparing your compensation expectations, consider your experience level, technical skill set, and the specific location of the role. Use this data to guide your discussions with recruiters and ensure your expectations align with market standards.