Backend Software Engineer Intern - C#/Java & AI Workflows (Undergraduate)

WEX Inc.; California (MO); Hybrid; USD 37,000 - 48,000; Full time

Benefits offered by this job

Health insurance

Dental insurance

Vision insurance

Retirement plan

Paid time off

Health Savings Account (HSA)

Flexible Spending Accounts

Life insurance

Disability insurance

Tuition reimbursement

Job summary

WEX Inc. seeks a Software Engineer Intern to build resilient backend systems and AI-enabled workflows. You will work with engineers and product managers to design scalable APIs, develop microservices, and deploy in cloud environments using modern AI tooling.

You’ll gain real-world experience in API design, backend processing, and data integrations with SQL Server and Microsoft Azure, while learning through mentorship and hands-on projects across multiple locations.

Qualifications

• Pursuing a Bachelor’s degree in Computer Science or related field, with at least sophomore standing at internship start.
• Proficiency in C# (preferred) or Java and strong SQL/SQL Server skills.
• Familiarity with API design, backend architectures, and Azure cloud services.

Responsibilities

• Develop backend services, RESTful APIs, and microservices using C# or Java.
• Participate in database design and cloud deployments (SQL Server, Azure).
• Apply AI tooling (Cursor, Copilot, MCPs) to accelerate development and prototyping.
• Collaborate with senior engineers on microservices and event-driven architectures (Kafka).

Skills

C#

Java

SQL

Azure

API design

Microservices

Kafka

AI tools

Education

Bachelor's degree in CS (in progress)

Job description

WEX is a global commerce platform that has been simplifying the way businesses operate for over 40 years. Our purpose is simple: to reduce administrative burdens, streamline payments, and manage mobility. With a team of over 7,200 professionals across 16 countries. Our specialties are employee benefits, business payments, and fleet/mobility solutions. We support more than 20 million SaaS accounts, 8 million Health Savings Accounts, and 19+ million vehicles worldwide. We're a growing company with a history of innovation and a focus on our customers, making this a great place to grow your career.

WEX's comprehensive and market competitive benefits are designed to support your personal and professional well-being.

WEX is a global commerce platform that helps businesses solve for operational complexities like employee benefits, managing and mobilizing fleets, and streamlining payments. With over 6,500 employees, we work with large and small companies in more than 200 countries and territories, and can tailor our services to meet the unique needs of their businesses. We hire people who share our passion for continuous innovation and client service that is unparalleled in the industry. Offering comprehensive and market competitive benefits, our offerings are designed to support your personal and professional well-being.

The WEX Summer Internship Program: Learn, Lead, and Make an Impact

Our 13-week paid internship program, running from late May to mid-August, is a chance for you to gain real-world experience and develop your skills. Recruiting begins in September and continues through November at our various locations across the U.S. You won't just be a bystander; you'll work on impactful projects and contribute to WEX's mission. We provide mentorship, professional development, and weekly learning experiences to help you build confidence and leadership skills. High-performing interns may even get the chance to lead their own initiatives. We offer remote, hybrid, and onsite options for flexibility, and our goal is to bring top interns back full-time or offer them extended roles during the school year. Imagine starting your career with a company that is building what's next. Your future starts here.

About the Team / Role

As a Software Engineer Intern, you will work alongside engineers and Product Managers to build resilient backend systems and AI-integrated workflows. You will gain hands-on experience designing scalable APIs, working in cloud environments, and leveraging modern AI toolchains.

How you'll make an impact

• Develop Backend Services: Design and implement RESTful APIs, microservices, and backend processing pipelines using C# or Java.
• Database & Cloud Integration: Write efficient SQL queries for SQL Server and support deployments on Microsoft Azure.
• AI-Integrated SDLC: Leverage modern AI tools (Cursor, Copilot, MCPs, AI APIs) for spec-driven development, rapid prototyping, and automated task execution.
• Learn & Collaborate: Partner with senior engineers to apply best practices in microservices and message-driven architectures (e.g., Kafka).

Experience you'll bring

• Educational Foundation: Currently pursuing a Bachelor's degree in Computer Science, Machine Learning, Software Engineering, or related field and will have completed at least your Sophomore year of school at the start of the internship.
• Proficiency in C# (preferred) or Java, along with strong standard database skills (SQL / SQL Server).
• Solid understanding of API design principles, backend processing architectures, and Microsoft Azure.
• Practical experience using AI coding assistants or APIs (e.g., Cursor, Copilot, MCPs) to accelerate development.
• Knowledge of event streaming technologies (e.g., Kafka) or messaging architectures is a plus.

Compensation & Benefits

The base pay range represents the anticipated low and high end of the pay range for this position. Actual pay rates will vary and will be based on various factors, such as your qualifications, skills, competencies, and proficiency for the role. Base pay is one component of WEX's total compensation package. Most sales positions are eligible for commission under the terms of an applicable plan. Non-sales roles are typically eligible for a quarterly or annual bonus based on their role and applicable plan.

Pay Range: $27.00 - $35.00

• Benefits include health, dental and vision insurances, retirement savings plan, paid time off, health savings account, flexible spending accounts, life insurance, disability insurance, tuition reimbursement, and more.

Equal Opportunity Statement

WEX is an equal opportunity employer committed to diversity and inclusion in the workplace. All qualified applicants will receive consideration for employment without regard to sex, race, color, age, national origin, religion, sexual orientation, gender identity, protected veteran status, disability or other protected status. WEX promotes a drug-free workplace. Qualified individuals with a disability have the right to request a reasonable accommodation. If you require a reasonable accommodation as a result of your disability at any point in the job application process, please submit your request through our Reasonable Accommodation Request Form. This form is for accommodation requests only and cannot be used to inquire about the status of applications.