As a DevOps Engineer at Barclays, you are positioned at the intersection of high-performance financial technology and global scale reliability. This role is not just about maintaining pipelines; it is about ensuring the absolute resilience of systems that process massive volumes of financial data, customer identities, and trading interactions. You will be expected to bridge the gap between software engineering and IT operations, driving automation and operational excellence across critical business units.

Your work directly impacts the stability and security of representative domains like Customer Identity and Access Management (CIAM) and high-frequency data analytics. Because Barclays operates in a highly regulated, fast-paced financial environment, your ability to design robust Site Reliability Engineering (SRE) practices ensures that millions of users and internal stakeholders experience zero disruption. The scale and complexity of these systems require a unique blend of traditional infrastructure knowledge and modern automation skills.

Expect to be challenged daily. You will navigate complex legacy integrations while pushing forward modern, scalable architectures. Whether you are optimizing a kdb+ time-series database for a trading desk or scripting automated failovers in Python, the work you do here forms the backbone of the bank's digital infrastructure. This role demands technical rigor, but it rewards you with the opportunity to architect solutions that drive the future of global finance.

The following questions are representative of what candidates face during the Barclays interview process. They are drawn from real experiences to illustrate the patterns and depth of knowledge expected. Use these to guide your study, rather than memorizing them as a definitive list.

Technical & Scripting

This category tests your hands-on ability to interact with operating systems and write functional automation code.

• How do you check for memory leaks or high CPU utilization on a Linux server?
• Write a Python script to parse a large log file and extract all IP addresses that have generated a 404 error.

Preparing for a technical interview at Barclays requires a strategic approach. You must demonstrate not only that you can write a script or configure a server, but also that you understand the systemic impact of your technical decisions.

Focus your preparation on the following key evaluation criteria:

• Technical Depth and Automation – Interviewers will evaluate your hands-on proficiency with core technologies like Linux, Python, and SQL. You can demonstrate strength here by explaining how you use these tools to automate toil, build resilient CI/CD pipelines, and manage complex configurations at scale.
• SRE and Scenario Troubleshooting – This criterion tests your ability to navigate production incidents. Barclays values engineers who can systematically diagnose issues under pressure. Show your strength by walking interviewers through your incident response methodology, focusing on root cause analysis and preventative engineering.
• Domain-Specific System Knowledge – Given the financial nature of the business, you will be evaluated on your familiarity with specialized, high-throughput systems like kdb+. You demonstrate this by discussing how you monitor, scale, and maintain performance-critical databases and infrastructure.
• Critical Thinking and Communication – Interviewers want to see how you approach abstract problems and communicate your solutions to a panel. You excel here by thinking out loud, clarifying ambiguous requirements, and collaborating with your interviewers to reach optimal architectural decisions.

The hiring process for a DevOps Engineer at Barclays is thorough and designed to test both your immediate technical reflexes and your deep architectural thinking. After submitting your application through the internal portal, expect a waiting period—often up to a month—before the initial contact. The first live interaction is typically a 30-minute panel interview featuring two team members. This rapid-fire session focuses on your resume, high-level technical concepts, and your alignment with the specific role requirements.

If you pass the initial screen, you will move into the core technical loop, which generally consists of three distinct rounds. The first is a Critical Thinking and Technical round, diving deeply into core engineering principles, database fundamentals, and specialized tech like kdb+. The second round is an SRE Scenario round, where you will face simulated production outages and be expected to troubleshoot using your knowledge of Linux, Python, and SQL. Finally, you will have an HR and leadership round focused on behavioral fit, culture, and offer logistics.

What makes this process distinctive is the heavy emphasis on scenario-based troubleshooting rather than isolated algorithm puzzles. Barclays prioritizes engineers who can apply their knowledge to real-world financial infrastructure problems, heavily weighting your ability to maintain composure during simulated outages.

The visual timeline above outlines the typical progression from the initial online application through the final HR and offer stages. You should use this to pace your preparation, focusing first on high-level system concepts for the initial panel, and then diving deeply into specific technical troubleshooting scenarios for the onsite loop. Keep in mind that exact timelines may vary slightly depending on your location, such as London or Pune, but the core evaluation stages remain consistent.

To succeed in the Barclays interview loop, you must prove your competence across several distinct technical and operational domains. Interviewers will look for practical experience, not just theoretical knowledge.

Core Infrastructure and Scripting

This area forms the foundation of your daily responsibilities. Interviewers need to know you can navigate server environments and automate repetitive tasks efficiently. Strong performance here means writing clean, error-handled code and demonstrating a deep understanding of OS-level operations.

Be ready to go over:

• Linux Internals – Process management, file systems, networking commands, and performance tuning.
• Python Automation – Writing scripts to interact with APIs, parse logs, and automate infrastructure deployments.
• SQL and Data Management – Writing complex queries, understanding indexing, and managing database migrations.
• Advanced concepts (less common) – Kernel tuning, custom bash scripting for legacy systems, and advanced network protocol troubleshooting.

Example questions or scenarios:

• "Walk me through how you would use Python to automate the cleanup of stale logs across 500 Linux servers."
• "You notice a sudden spike in CPU usage on a critical Linux node. What commands do you run to diagnose the issue?"
• "Explain how you would write a SQL query to identify anomalous transaction patterns in a high-volume database."

SRE Scenarios and Incident Response

As a DevOps Engineer, you are the first line of defense when systems fail. This area evaluates your ability to handle stress, isolate problems, and restore service. A strong candidate will use a structured methodology to triage issues, rather than guessing at solutions.

Be ready to go over:

• Incident Triage – How you assess the severity of an alert and prioritize your response.
• Root Cause Analysis (RCA) – Your process for conducting post-mortems and ensuring issues do not recur.
• Monitoring and Alerting – Designing effective telemetry using modern observability tools.
• Advanced concepts (less common) – Chaos engineering principles, designing self-healing infrastructure, and managing global failovers.

Example questions or scenarios:

• "A deployment just went out and the CIAM authentication service is returning 500 errors. Walk me through your troubleshooting steps."
• "How do you determine if an alert is actionable versus just noise? How would you tune a noisy alerting system?"
• "Describe a time you handled a severe production outage. What was the root cause and how did you fix it?"

High-Performance Data Systems (kdb+)

Because Barclays handles massive amounts of trading and financial data, familiarity with specialized systems is a major differentiator. While you may not need to be a kdb+ developer, you must understand how to support and maintain these environments.

Be ready to go over:

• kdb+ Fundamentals – Understanding the basics of time-series databases and how they differ from relational databases.
• Performance Monitoring – Tracking query performance, memory usage, and disk I/O for high-throughput systems.
• Data Pipeline Integration – How core data systems integrate with broader CI/CD and infrastructure pipelines.
• Advanced concepts (less common) – q language basics, tick architecture troubleshooting, and optimizing IPC (Inter-Process Communication).

Example questions or scenarios:

• "How would you monitor a kdb+ instance to ensure it isn't running out of memory during a high-volume trading day?"
• "Explain the difference in infrastructure requirements between a standard PostgreSQL database and a time-series database like kdb+."
• "What steps would you take if a core data pipeline suddenly started experiencing high latency?"