Backend Engineer

• Join a product team building payment infrastructure for merchants and partner platforms
• Own end-to-end payment flows in TypeScript/NestJS services, including authorization, capture, void, refund, dispute handling, and payout initiation and confirmation
• Build and maintain acquirer and processor integrations using clean internal abstractions
• Design embedded and hosted checkout experiences, including hosted fields, iframes, and tokenization, to minimize PCI scope
• Implement fee calculation and rate logic, including tiers, interchange-plus, flat structures, rounding rules, special rates, and edge cases
• Build reconciliation and settlement layers matching processor reports and settlement files against internal records
• Design event handling with idempotency keys, out-of-order and duplicate webhooks, retries with backoff, and state machines
• Integrate fraud, bank-account verification, and KYC providers and tune decisioning against real outcomes
• Handle ACH mechanics, including submission windows, returns, return codes, NOCs, and retry rules
• Maintain domain correctness, complete audit trails, and reconciliation evidence
• Act as the team's payments expert, advise product on rail capabilities, and review payment-adjacent code
• Collaborate daily with a US-based team with 4–6 hours of overlap with US Central Time

Senior Backend Engineer – Payments, Go, TypeScript, Node.js

• Quickly learn new technologies
• Demonstrate and prove current technical level
• Work with a mentor to prepare a personal roadmap and address knowledge gaps
• Raise problems and blockers to the mentor in a timely manner
• Study recommended materials and remain open to feedback and constructive criticism
• Show progress toward achieving the Junior Java Developer level within the defined timeframe

Java Developer Intern

• Architect, implement, and maintain scalable architecture and RESTful APIs using Java and Spring
• Engineer reliable backend services to manage multi-step business logic, status lifecycles, and event-driven notifications
• Design secure interfaces connecting internal modules with external systems while adhering to healthcare data privacy principles
• Optimize relational database schemas and query performance
• Enforce software engineering best practices through code reviews, automated unit/integration testing, and technical mentoring

Senior Java Developer

• Build high-performance backend services and APIs for enterprise-grade SaaS applications
• Develop scalable, secure Node.js microservices and Salesforce ecosystem integrations
• Build modern front-end experiences with Vue.js and TypeScript
• Develop CI/CD pipeline tooling, automation frameworks, and developer productivity infrastructure
• Implement real-time data processing and event-driven architectures for sensitive enterprise data at scale
• Work directly with engineering leadership, product managers, and the CEO
• Own significant parts of the architecture and ship production code used by enterprise customers
• Own systems end-to-end and contribute to the company’s long-term growth

Senior Node.js Developer

• Develop and maintain backend and frontend services using .NET 5 and Angular 16
• Develop system integrations with third-party providers, including SMS, email, and payment systems
• Work with MS SQL databases, including data modeling, performance optimization, and change management
• Work with Agentic.ai
• Participate in system architecture discussions and technical decisions
• Collaborate closely with the Team Lead and development team
• Take ownership of assigned components and ensure their stability in production
• Participate in estimation, planning, and Jira-based workflows
• Be available for paid on-call duty on weekends, with emergency response within 1 hour, approximately 1–2 times per month

Mid .NET, Angular

• Analyze technical requirements and design solutions accordingly
• Develop and build software components based on specifications
• Conduct code reviews to ensure quality and standards
• Write and maintain unit tests
• Participate actively in project-related meetings and discussions

Middle/Senior Java Integration Developer

• Own the Rust core, including service logic, networking, data synchronization, and offline mode
• Build and maintain native layers using Kotlin with JNI, Swift with C interop, and C# with P/Invoke for Unity
• Design and maintain the API used by internal product teams, including backward compatibility
• Handle builds, packaging, and releases across all supported platforms

Backend Engineer jobs in Ukraine