Staff Engineer

Maine Tech Hub; Portland (ME); On-site; USD 141,000 - 173,000; Full time

Benefits offered by this job

Health insurance

Dental insurance

Vision insurance

Retirement plan

Paid time off

Job summary

WEX Inc. in South Portland, Maine, is seeking a Staff Software Engineer to architect and lead migration of the Digital Credit Application platform.

You will drive a shift from a legacy monolith to a cloud-native, microservices-based Java/Spring Boot stack, enabling rapid experimentation and AI-enabled decisioning. Lead the API ecosystem, guide zero-downtime migrations, and mentor engineers while partnering with Data Science for real-time credit decisioning.

Qualifications

• 10+ years of backend software engineering experience in fintech or lending.

Responsibilities

• Architectural migration of core credit logic from legacy monoliths to cloud-native microservices.

Skills

Java

Spring Boot

Microservices

AWS

API Design

Kafka/RabbitMQ

Technical Leadership

AI Tools (Copilot/Cursor)

Education

Bachelor's degree in Computer Science or related field

Tools

OpenTelemetry

GitHub Copilot

Cursor

OpenAPI/Swagger

Job description

at WEX Inc. in South PortlandSouth Portland, Maine, United States

Job Description

About the team / Role:
As a Staff Software Engineer, you will be the primary architect and execution lead for leading the platform changes for the Digital Credit Application.

We are pivoting from a legacy monolith to a high-performance, pluggable API ecosystem. Your mission is to decouple core adjudication logic, enable rapid A/B testing of the customer journey, and lay the technical foundation for future AI-driven chat and automated decisioning experiences.

This is a high-impact role designed for a true "builder" who thrives on the duality of supporting a live production environment while aggressively migrating mission-critical services to a modern, microservices-based backbone. You will encounter varied customer scenarios where your out-of-the-box approach is a better fit than standard industry practices. We expect you to make a true difference for the customer, leveraging technology and AI to best serve and solve for good.

The AI Edge: We are a forward-thinking engineering org. You are expected to be an expert in leveraging AI Software Development Lifecycle (ADLC) tools (e.g., GitHub Copilot, Cursor, Amazon Q, LLM-based code gen and architecture agents) to accelerate migration, write bulletproof tests, and automate documentation.
How you'll make an impact:
Architectural Migration & Strategy:
Strangler Fig Migration: Lead the decoupling of core credit application logic out of the legacy monolith and into a scalable, cloud-native Java/Spring Boot micro services environment.
Migration with Zero Downtime: Design and execute high-volume traffic migration strategies from legacy systems to new stacks seamlessly without disrupting live customers.
Salesforce Proficiency: A significant portion of existing systems is embedded within various Salesforce capabilities throughout the application lifecycle. Proficiency in Salesforce is a strong advantage, as different integrations will require the new stack to support bidirectional data and state synchronization within the Salesforce ecosystem.
Pluggable Adjudication & API Ecosystem:
Modular Architecture: Design and implement a modular adjudication layer allowing the business to swap or update credit rules and third-party data providers without impacting core application flows.
API-First Design: Build and maintain robust, versioned REST/gRPC APIs that support a multi-channel experience (Mobile, Web, and future AI Chat interfaces).
A/B Strategy Enablement: Engineer backend infrastructure for dynamic routing and experimentation, allowing real-time testing of various application flows.
AI Readiness & Process Acceleration:
AI DLC Mastery: Champion the use of AI tools across the development lifecycle to write code faster, refactor legacy code into modern Java, and generate robust test suites.
Data Science Partnership: Partner with Data Science teams to ensure data pipelines and backend schemas are optimized for LLM integration and real-time credit decisioning models.

Operational Excellence & Leadership:
Observability & CI/CD: Establish rigorous standards for CI/CD, observability (OpenTelemetry), and automated contract testing.
Technical Mentorship: Provide guidance to mid-level and senior engineers, fostering a culture of high engineering standards, clean code, and AI-assisted productivity.Experience you will bring:
Technical Architecture & Stack:
10+ Years of Engineering Excellence: Proven track record in backend architecture, specifically within Fintech, Lending, or Credit systems.
Modern Java Stack: Expert-level proficiency in Java 17/21, Spring Boot 3.x, and Spring Cloud.
Monolith-to-Distributed Migration: Significant experience extracting tightly coupled business logic from legacy backends into external, scalable cloud microservices (AWS).
Complex Adjudication & Rules Engines: Experience building or implementing rules engines (e.g., Drools, Camunda, or custom JSON-logic) for automated decisioning.
Event-Driven Design: Deep experience with Kafka or RabbitMQ for maintaining asynchronous data consistency between the new API layer and legacy systems of record during migration phases.
Contract-First Development: Strict adherence to API contracts (OpenAPI/Swagger) to ensure seamless collaboration with frontend teams.
AI & Modern Delivery Tools:
AI DLC Proficiency: Hands-on experience using AI coding assistants (Cursor, Copilot, etc.) to optimize workflows, refactor legacy code, and accelerate delivery.

Leadership & Education:
Strong analytical skills and a proven capability in resolving complex, cross-functional problems.
Excellent written and verbal communication skills; ability to present complex technical concepts clearly to stakeholders.
Bachelor's degree in Computer Science or a related technical field.

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. WEX's comprehensive and market competitive benefits are designed to support your personal and professional well-being. 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. For more information, check out the "About Us" section.

Pay Range: $140,600.00 - $173,100.00

Equal Opportunity Employer/Vets/Disability