Java Application Developer

Sr. Software Engineer – International Mobility

About the Team / Role

We are seeking a seasoned
Sr. Software Engineer
in the
WEX Mobility Engineering organization
. This role will sit within the
International Mobility team
, which caters to fleet management and mobility payments solutions for large customers and partners in the
EU and APAC
regions.

The International Mobility development team spans across
India, UK, and USA
.

Our Mobility systems provide
SaaS and API solutions
to a variety of customers.

WEX Mobility products
enable credit issuance to fleet companies and their employees through WEX or co-branded credit cards, usable at fueling stations and select merchants.

We provide fleet managers and operators with the flexibility to configure spend controls—restricting fleet members to use their cards at configured merchants, amounts, and velocity limits.

How You'll Make an Impact

• Design, develop, and maintain robust, scalable, and high-performance object-oriented code in backend services.
• Develop public REST APIs using Java and internal gRPC APIs for inter-service and inter-system communication.
• Craft system designs, lead design decisions, and drive alignment with other senior engineers.
• Write automated unit, integration, end-to-end, concurrency, and load/performance tests.
• Analyze existing systems to identify bottlenecks and technical debt; implement scalability and stability improvements.
• Implement automation for testing, monitoring, healing, and scaling applications.
• Contribute to CI/CD practices to reduce time to market.
• Collaborate with cross-functional teams (product managers, designers, engineers) to define and implement new features.
• Conduct code reviews, mentor junior and mid-level engineers, and promote engineering best practices.
• Troubleshoot complex issues, devise fixes, and author root cause analysis documents to ensure lasting performance and reliability.
• Conduct comparative analyses of competing technologies to evaluate pros and cons.
• Maintain robust documentation, including design docs, runbooks, change management docs, and readiness plans.
• Provide live-site support for production applications, ensuring rapid incident resolution and continuous improvement.
• Drive cross-team projects as a single-threaded owner (STO) or tech lead, actively unblocking other engineers.

Experience You'll Bring

• Bachelor's degree in
  Computer Science
  or
  Software Engineering
  .
• 5+ years
  of professional experience in software engineering.
• Strong understanding of
  data structures, algorithms, OOP design,
  and problem-solving.
• Expertise in designing and developing
  internet-scale services
  with scalability, availability, security, and reliability.
• Excellent written and verbal communication skills with a collaborative mindset.
• Proficiency in backend development using
  Java or C#
  , frameworks like
  Spring Boot
  , and building/optimizing RESTful APIs,
  ODATA framework
  , and
  SQL
  .

Preferred Qualifications

• Master's degree in
  Computer Science
  or
  Software Engineering
  .
• 5+ years
  of software engineering experience.
• Experience with
  event-driven architecture
  and tools such as
  Kafka
  .
• Experience working on
  card payments
  or financial systems.
• Familiarity with
  cloud-native architecture
  ,
  Docker
  , and
  Kubernetes
  .
• Awareness of
  API security
  and
  PCI DSS
  compliance requirements.
• Ability to work on existing codebases, contribute improvements, and adapt to legacy system constraints.

Roles & Responsibilities

• Design, develop, and maintain robust, scalable, and high-performance backend code using
  Java
  and
  Spring Boot
  .
• Develop public
  REST APIs
  and internal
  gRPC APIs
  for seamless inter-service communication.
• Lead system design efforts, making critical design decisions and ensuring cross-functional alignment.
• Write and maintain comprehensive automated testing suites (unit, integration, performance).
• Identify bottlenecks and technical debt, implementing improvements for scalability and stability.
• Automate processes for testing, monitoring, and deployment to enhance efficiency.
• Collaborate with product managers, designers, and engineers to define and implement new features.
• Conduct thorough code reviews and mentor engineers while promoting best practices.
• Troubleshoot complex technical issues and document long-term solutions.
• Stay updated with emerging technologies and conduct comparative analyses to guide design decisions.

Our Ideal Candidate

• Strong foundation in
  Java
  and
  Middleware technologies
  .
• Expertise in
  Java + Spring Boot + Microservices
  development for scalable architectures.
• Deep understanding of
  RESTful APIs
  and
  middleware integration
  .
• Proven experience in developing enterprise-level applications leveraging
  Java
  and
  cloud platforms
  .
• Experience range:
  5 to 9 years
  , capable of leading projects and mentoring developers.
• Ability to drive technical decision-making and enforce best practices.
• Strong grasp of
  software design principles
  and
  SOLID
  principles for efficient and reusable code.
• Experience with
  containerization
  (Docker) and
  orchestration
  (Kubernetes).
• Excellent analytical and problem-solving abilities.
• Effective collaboration with cross-functional teams and strong communication skills.
• Education:
  Bachelor's degree in Computer Science or Software Engineering (mandatory).
• Certifications (Preferred):
• Oracle Certified Professional, Java SE 11 Developer
• AWS Certified Solutions Architect – Associate