Senior Backend Engineer

About Outside Hire
Outside Hire is a growing outsourcing company with over 75 employees, building custom products and solutions for our clients. We're dynamic, fast-paced, and always evolving

About the Role

Senior Backend Engineers are responsible for implementing core payment platform services including API Gateway management, payment processing workflows, transaction reporting, and third-party integrations. Each engineer owns specific service domains while collaborating on cross-service integration and shared infrastructure components using modern JVM-based technology stacks on AWS.

Location Remote (core hours required) Experience Senior (5+ years) Type Full-time Travel Minimal Core Responsibilities
Service Implementation

Develop and maintain microservices using modern JVM frameworks (Quarkus, Spring Boot, or similar) and AWS cloud services

API Development

Build RESTful APIs, webhook systems, and integration adapters following OpenAPI specifications and industry best practices

Data Management

Implement robust data access layers using JPA/Hibernate or similar ORMs, design efficient database schemas, and optimize query performance

Integration Development

Build integrations with payment processors, authentication providers, and internal platform services using modern integration patterns

Event-Driven Architecture

Implement messaging and event sourcing patterns for reliable asynchronous processing and system communication

Performance Optimization

Ensure services meet strict performance SLAs including sub-second response times and high transaction throughput

Security Implementation

Implement security best practices including encryption, OAuth/JWT authentication, and compliance with payment industry standards

AI-Assisted Development

Leverage AI coding assistants and tools to accelerate development, improve code quality, and enhance problem-solving capabilities

Testing & Quality

Write comprehensive automated tests, participate in code review processes, and maintain high code quality standards

Documentation

Maintain technical documentation, API specifications, and operational guides using modern documentation-as-code approaches

Required Technical Skills
JVM Platform Development (5+ years)

Experience with JVM-based backend development using Java and at least one additional JVM language (Kotlin, Groovy, Scala, etc.)

Modern Frameworks

Strong experience with dependency injection frameworks such as Spring Boot, Quarkus, Micronaut, or similar CDI platforms

AWS Cloud Services

• Compute: EC2, ECS, Lambda
• Storage: S3, RDS
• Integration: API Gateway, SQS, SNS

Database Development

Advanced experience with PostgreSQL or MySQL, JPA/Hibernate or similar ORMs, database design, and query optimization

API Development

RESTful API design, OpenAPI/Swagger documentation, webhook implementation, and API versioning strategies

Messaging & Events

Experience with message queues, event-driven architectures, and asynchronous processing patterns

Authentication & Authorization

Understanding of OAuth 2.0, JWT, and experience with authentication providers (Auth0, Supabase, Keycloak, etc.)

Security

Knowledge of encryption, secure coding practices, and compliance requirements (PCI-DSS, GDPR)

Testing

Unit testing frameworks (JUnit, Kotest), integration testing, and mocking libraries

Preferred Technologies & Skills Docker Kubernetes AWS ECS/EKS Event Sourcing CQRS CloudWatch Maven Gradle CircleCI Jenkins GitLab CIPayment Domain Knowledge

Experience with payment processing systems, financial transactions, settlement workflows, or similar fintech applications

AI-Assisted Development Experience

• Experience using AI coding assistants (GitHub Copilot, Cursor, Cody, or similar)
• Understanding of effective prompt engineering and code review of AI-generated code
• Ability to critically evaluate AI suggestions and maintain security/quality standards
• Enthusiasm for leveraging emerging AI capabilities

Technology Stack OverviewCore Platform Technologies Backend Framework: Quarkus cloud-native, supersonic subatomic Java)
Primary Languages: Kotlin (primary), Java (legacy)
Database: PostgreSQL 14+ with Flyway migrations
Authentication & Identity

• Supabase Auth (GoTrue) for user authentication
• JWT-based authentication with RS256 signing
• OAuth 2.0 client credentials flow for service-to-service
• Role-based access control (RBAC) and Attribute-based access control (ABAC)

AWS Infrastructure

• ECS for container orchestration
• RDS for managed PostgreSQL
• CloudFront for CDN and static assets
• S3 for file storage
• Application Load Balancer
• CloudWatch for monitoring

API & Integration

• Kong API Gateway for routing, rate limiting, and security
• OpenAPI 3.0 specifications
• RESTful API design
• Webhook system for event-driven integrations

Development Workflow & Tools

• Git with feature branch workflow
• CircleCI for CI/CD
• Docker Compose for local development
• 90% code coverage requirements
• Terraform for infrastructure management

What Makes This Role Unique
Modern Architecture Patterns

Microservices Architecture: Work with independently deployable services including core payment processing API, dedicated reporting service, payment simulation service, and independent frontend applications.

Event-Driven Design: Build systems with webhook event generation, transaction notifications, real-time payment updates, and external processor integrations.

Performance at Scale:

• Sub-2-second payment authorization flows

• Sub-300ms API response times (95th percentile)

• Batch transaction processing (10K+ transactions)
Real-World Payment Domain Challenges

• Multi-Party Settlement: Partner fees, merchant settlements, dynamic surcharges, TruCost engine
• Compliance & Security: PCI DSS compliance, audit trails, encryption, secure credential management
• Third-Party Integrations: Payment gateways, KYC verification, banking systems, multi-processor support

AI-Enhanced Development Culture
How We Use AI

• Code generation and completion for boilerplate reduction
• API client generation from OpenAPI specs
• Test case generation and enhancement
• Architecture exploration and pattern recommendations
• Bug investigation and performance optimization
• Faster codebase understanding and onboarding

What We Expect

• Critical Thinking: AI is a powerful assistant, not a replacement for engineering judgment
• Continuous Improvement: Stay current with AI tooling evolution
• Quality Standards: All code must meet test coverage, security, and performance requirements

Growth Opportunities

Technical Growth

• Domain Expertise: Become an expert in payment processing and fintech
• Architectural Evolution: Participate in architectural decision-making
• Emerging Technologies: Native compilation with GraalVM, ML/AI integration for fraud detection
  
  

Career Path

• Technical track: Senior → Staff → Principal Engineer
• Specialization: Payment domain expert, Performance specialist, Security champion
• Leadership: Technical lead opportunities

Why Outside Hire?

• Inclusive Environment: Dynamic work environment that values creativity and collaboration
• Cutting-Edge Projects: Modern, well-architected platform with best-in-class tools
• Impact: Build systems that process real financial transactions
• Modern Stack: Quarkus, Kotlin, AWS, and AI coding assistants
• Competitive Benefits: Competitive salary, remote work, professional development
• Growth Culture: Continuous learning, innovation, and recognition
• Work-Life Balance: Flexible hours, remote-first, sustainable pace

Ready to Apply?

If you're excited about building robust, scalable payment systems using modern JVM technologies, working with cutting-edge AI tools, and contributing to a platform that processes real financial transactions, we want to hear from you

What to Include in Your Application

1. Resume highlighting relevant JVM and cloud experience 2. GitHub profile or code samples (if available) 3. Brief description of your most challenging technical project 4. Your experience with AI coding assistants (if any) 5. Why you're interested in payment platform development

Outside Hire is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees.

Last Updated: December 2025

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