Hi everyone! In this article, I’ll talk about my interview with American Express for a 6-month internship. “American Express” will always have a special place in my heart. At the end, you’ll find out why.
American Express held an AmExpert Event in 2021. Only a few colleges were allowed to attend, and luckily my school was one of them! The hiring process started with a coding round, which was more like a hackathon, and then there were a series of interviews. Now I’ll tell you everything you need to know about the process, along with some tips and tricks to get you going.
If you have an American Express software engineering interview coming up, preparation is key American Express is well known for asking challenging technical questions to assess your programming abilities and problem-solving skills
This comprehensive guide covers the 15 most common American Express software engineer interview questions with detailed examples of winning answers to help you ace your interview. Let’s get started!
1. Explain how you would design an ATM system.
This classic system design question tests your technical knowledge and analytical abilities Discuss how you would
- Gather requirements on features like cash withdrawals, deposits, transfers, etc.
- Define core objects like Account, Customer, Transaction, CashDispenser
- Design key workflows for transactions, authentication, bank communications
- Create class and sequence diagrams depicting logical components and interactions
- Select optimal data structures to store account data efficiently
- Incorporate security features like PIN verification and encryption
- Consider scalability needs like load balancing, caching, and database partitioning
Illustrate your points using clear diagrams and emphasize your focus on robustness, extensibility and efficiency.
2. How would you detect and prevent credit card fraud?
Fraud detection is crucial in financial systems. Outline approaches like:
- Tracking spending patterns to flag anomalies
- Analyzing typical card usage by location to detect suspicious activity
- Implementing thresholds for maximum transaction amounts
- Requiring additional verification like one-time passwords for large purchases
- Leveraging AI and machine learning to continuously improve fraud detection
Discuss balancing security, user experience and privacy concerns. Provide examples of how you’ve built effective fraud prevention measures.
3. Design a parking lot using object-oriented principles.
This OO design question tests your conceptual modeling skills. Discuss defining core objects like ParkingLot, Level, ParkingSpace, Ticket with attributes and behaviors. Outline key relationships like:
- A ParkingLot has many Levels
- A Level has many ParkingSpaces
- A Ticket is issued to a Vehicle upon entry
- ParkingSpace availability status can be updated
Emphasize encapsulation, inheritance and polymorphism principles you would leverage in your design.
4. How would you improve the performance of our credit card rewards program web application?
This question evaluates your knowledge of application optimization techniques. Discuss approaches like:
- Profiling load testing to identify bottlenecks
- Tuning database queries and indexes to reduce latency
- Implementing caching mechanisms for faster data access
- Asynchronously loading page components to improve perceived speed
- Ensuring images and scripts are compressed and CDN-hosted
- Minifying CSS, JS and HTML files to optimize bandwidth utilization
Providing quantifiable metrics on expected gains strengthens your answer.
5. Design a highly available system to process credit card transactions.
This assesses your understanding of availability and recovery principles. Discuss:
- Implementing redundancy using active-passive servers
- Database replication across data centers to ensure uptime
- Using health checks and load balancers to route traffic
- Building retry mechanisms to handle connection issues
- Logging transactions asynchronously to decouple systems
- Leveraging replication and data sharding for scalability
Emphasize how your design focuses on eliminating single points of failure.
6. How would you go about debugging a slow-running production database query?
This evaluates your grasp of debugging methodology. Discuss:
- Reviewing slow query logs to identify worst offenders
- Analyzing explain plans to isolate performance issues
- Tweaking indexes, caching, queries based on insights
- Tuning database parameters like memory allocation
- Monitoring system resource usage to pinpoint bottlenecks
- Recommending hardware upgrades like adding memory
Highlight debugging best practices like hypothesizing before testing.
7. How do you ensure software quality in the face of tight deadlines?
This behavioral question tests your understanding of managing tradeoffs between speed and quality. Discuss:
- Prioritizing requirements to focus on mission-critical features
- Allocating time for proper design and code reviews
- Balancing test automation and exploratory testing
- Monitoring defects and regressions closely
- Involving QA earlier in lifecycle to detect issues sooner
- Recommending timeline adjustments if quality is severely impacted
Emphasize the importance of open communication with stakeholders when balancing competing demands.
8. How would you design Flipkart?
This high-level system design question assesses your ability to model real-world systems. Discuss:
- Key functionalities like product search/catalog, shopping cart, payment
- Components – front-end, APIs, application, database tiers
- Database schema design for products, orders, inventory, etc.
- Search indexing and optimization to enable fast queries
- Ranking algorithms like personalized recommendations
- Caching strategically to improve performance
- Load balancing across servers to handle traffic spikes
Provide diagrams illustrating the logical architecture and component interactions.
9. What principles and best practices do you follow for writing clean, maintainable code?
This evaluates your understanding of writing high-quality, production-ready code. Highlight principles like:
- Modular design with separation of concerns
- DRY (Don’t Repeat Yourself) to avoid duplication
- Loose coupling and high cohesion between components
- Commenting complex sections of code
- Meaningful naming conventions for variables, methods, classes
- Consistent formatting and project structure
Discuss your experience following style guides, linting, code reviews and refactoring to produce robust code.
10. How do you ensure web application security from common attacks like XSS, SQL injections?
This question tests your grasp of web security fundamentals. Discuss:
- Input validation and sanitization to prevent injection attacks
- Parameterized queries and prepared statements
- Escaping untrusted output on pages
- Implementing CORS policies on APIs
- Avoiding insecure direct object references
- Encrypting sensitive user data like passwords
- Conducting code reviews, penetration testing and audits
Providing specific examples of vulnerabilities you’ve addressed strengthens your response.
11. How do you optimize a credit card rewards program web application to handle significant traffic spikes?
This assesses your capacity planning and scaling abilities. Discuss:
- Setting performance benchmarks under regular and peak loads
- Vertical scaling by upgrading server resources
- Horizontal scaling by adding inexpensive servers behind a load balancer
- Enabling caching and CDNs to reduce database queries
- Asynchronously processing resource-intensive operations
- Tuning databases via indexing, partitioning and replication
Emphasize the importance of monitoring and autoscaling capabilities.
12. How would you migrate a legacy rewards program system to the cloud?
This evaluates your cloud migration expertise. Cover:
- Analyzing application dependencies, risks and target architecture
- Setting up equivalent infrastructure on cloud platforms
- Leveraging tools like AWS SCT for database migration
- Re-architecting components for cloud native design patterns
- Testing thoroughly and routing traffic gradually to production
- Decommissioning old infrastructure after cutover
Highlight the importance of planning, automation tools, and thorough testing.
13. How do you ensure high availability during a system upgrade?
This operational question tests your release management knowledge. Discuss:
- Implementing canary or blue-green deployments
- Using feature flags for gradual rollout
- Creating rollback procedures to revert quickly
- Cloning production data to test environments
- Scripting database schema migrations
- Monitoring metrics closely for regressions
- Having automated rollback processes and alerts
Emphasize the importance of minimizing downtime through these techniques.
14. How would you troubleshoot an outage in a globally distributed API?
This evaluates your distributed systems debugging skills. Discuss:
- Examining logs across various data centers and services
- Checking health dashboards for impacted components
- Tracing request flows to isolate service degradation
- Comparing configurations across regions to detect discrepancies
- Simulating requests to recreate failures
- Alerting impacted customers/teams quickly
- Post-mortem analysis to identify root cause
Highlight methodical triage of issues through logging, monitoring and collaboration.
15. How do you make technical decisions when building applications?
This assesses your technology decision-making approach. Discuss:
- Gathering requirements and analyzing tradeoffs
- Researching solutions used by competitors/industry leaders
- Prototyping and benchmarking alternatives where possible
- Evaluating factors like scalability, security, performance
- Soliciting feedback from team members and stakeholders
- Considering long-term maintenance costs
- Leveraging prior experience with technologies
Emphasize balancing business needs and technical constraints through informed analysis.
Round 2 — Technical Interview
There were no questions about anything else. I was only asked two coding questions about maps and comparator functions. I was also asked questions related to Python as I had it mentioned in my resume. The interviewer checked my knowledge of CS Fundamentals in depth. He asked me questions on topics such as ACID properties, IPv4 vs IPv6 and paging in OS. I was also asked to write several SQL queries for the given problem statements. The interviewer then moved on to discussing my projects that I had mentioned in my resume. He finally asked me if I knew anything about American Express and the work it does.
Point to note — Be prepared for everything that you have mentioned in your resume. American Express focuses on your resume minutely. You will be checked thoroughly on your resume. Additionally, you must be prepared to answer some basic HR questions on American Express as a firm.
Round 1 — Online Coding Assessment
This round was very different from the usual coding assessment rounds that we have. The twist is that the coding problems were based on real-life situations that most credit card companies face and how they try to lower the risk that comes with them. For each question, we were given raw data that had to be processed before you could use your logic. For the most part, the coding round was more like a hackathon. You were given problem statements that showed how well you could solve real-life problems. There were a total of five coding questions with medium-hard difficulty.
This round went pretty well for me and I got shortlisted for the interviews with American Express.
American Express Interview Questions with Answer Examples
FAQ
Is American Express interview difficult?
How many rounds of interviews does American Express have?
Is it hard to get a job at AmEx?
Can you become a software engineer at American Express?
Stepping into the competitive realm of software engineering at a prestigious company like American Express is no small feat. This Fortune 500 company is not just looking for someone who can code, but also a candidate who can innovate, problem-solve and contribute to their cutting-edge technology solutions.
Why does American Express need a financial software engineer?
American Express needs to ensure that their engineers can handle the complexities of financial software development while maintaining security and compliance standards. How to Answer: Example: I’ve spent several years developing financial technology software. My experience includes creating algorithms for risk management and predictive modeling.
What was the interview process like at American Express?
I interviewed at American Express It was an off-campus opportunity. First round was an online coding round consisting of 3 questions. After that was one technical interview mainly focused on projects, basic information about the company, the next round was an HR round. Why do you want to join american express? I interviewed at American Express
What is the American Express interview question?
This question aims to assess your ability to handle this complexity, especially within a leading global financial services company such as American Express. The interviewer wants to gauge your understanding of the nuances involved, from ensuring compatibility and security to managing the potential risks and costs. How to Answer:
