C# Software Engineer

Questions for candidates (sent answers to these with every sub):
1. How would you design a CI/CD pipeline for a .NET Core application running in Kubernetes? What tools and best practices would you use?

2. How would you design a logging and monitoring solution for a Kubernetes-based .NET Core microservices system? What tools would you use?

3. What libraries have you used to handle concurrency in your applications? Can you explain how you used those libraries in your projects?

4. Can you describe what Async and Await do? Can you also describe the TaskParallel library, and its functionality? What are good use cases for these concurrency libraries?

5. What is a deadlock in SQL Server, and how would you detect and prevent it?

6. What strategies would you use for sharding or partitioning a database?

7. What are the risks of violating the Open-Closed Principle? Can you provide an example where this happened in a project?

8. How would you refactor a class that violates multiple SOLID principles?

9. Explain how CQRS works and when you would use it?

10. How do you monitor and troubleshoot performance issues in a cloud-based .NET Core application?

11. What is the best use case for Azure Functions? How would you approach optimizing cost and performance in Azure?

12. Describe your experience working with distributed systems, event-driven architectures, and containerization tools.
Provide specific examples of how you have applied these technologies in past projects?

13. How does Kafka ensure message durability and reliability? What are the key differences between Kafka and RabbitMQ? When would you use one over the other?

Job Title: C# Senior Software Engineer
Location:

• Dallas (priority)
• Chicago (2 ^nd priority location)
• San Francisco

FullTime / Direct Hire
Project/Team:

• Team: 1 Lead; 5-6 Engineers
• ~4 teams working on similar initiatives for payments and fin tech
• HSA/FSA Cards - Wex works with a vendor that supplies the cards, Wex is responsible for the money on the cards, transactions, claims, etc for HSA/FSA
• This team is doing modernization
  • Working on time from using card/purchases and account notification and balance updating
  • Currently is a ~12hour window between purchase and notification (think about your credit card and getting immediate notification when used)
  • Working towards real-time alerts/recording
• Separate DevOps and QA teams

Sr Engineer

• Individual contributor role
• Strong C# development with TDD and BDD best practices
• 100% backend/server-side development
• Very heavy work with APIs
• Heavy on event drive development- utilizing Kafka
• Plan to move towards microservices
• SQL Server based and now Postgres (new for Wex) - potential to use NoSQL in the future
• Integrated Engineers - team expectation is everyone validates their code with unit and integration testing
  • Pushing to automate everything - 0% manual testing
  • Use ReadyAPI for API testing - but OK with any API validation domains
  • Will do mockups for cases too (experience with Jest or any other mocking technology is needed)
• Should be able to build CI/CD pipelines (have a DevOps ream that manages the majority)

Must Haves:

• C# - TDD and BDD best practices
• Extensive Rest API experience
• Kafka and event driven development
• Modern RDBMS (i.e. MS SQL, Postgres, MySQL)
• Azure - developing cloud-native apps/services
• Docker and CI/CD pipelines

Nice to Haves:

• NoSQL
• ReadyAPI

Interview:

• 30 Min with Tech Lead
• 1 hour panel with tech lead + other members of team