jefferywa

Senior Backend Engineer / Backend Tech Lead | Node.Js, Distributed Systems & De Fi

Senior Backend Engineer with 8+ years of experience designing and building high-load distributed systems across fintech, blockchain, DeFi, logistics, and mobility.

I specialize in Node.js, TypeScript, NestJS, PostgreSQL, and event-driven microservice architectures. I have experience owning backend systems across the full lifecycle: architecture and domain modeling, implementation, production delivery, observability, scaling, and long-term maintenance.

At P2P.org, I have worked on enterprise staking and DeFi products, including multi-chain platforms, staking APIs, wallet integrations, and protocol integrations across Ethereum, Solana, Cosmos, Polkadot, TON, NEAR, Sui, and Bitcoin.

My background also includes leading backend development, modernizing legacy platforms, designing new systems from scratch, introducing Domain-Driven Design and automated testing practices, and mentoring engineers.

Core technologies: Node.js, TypeScript, NestJS, Express, PostgreSQL, MySQL, Oracle, MongoDB, Redis, RabbitMQ, Kafka, Docker, Kubernetes, AWS, ArgoCD, Prometheus, Grafana, Kibana.

Architecture & engineering: Distributed systems, microservices, event-driven architecture, Domain-Driven Design, REST, GraphQL, WebSockets, system design, automated testing, observability, performance optimization, and technical leadership.

Blockchain & DeFi: Ethereum, Solana, Cosmos, Polkadot, TON, NEAR, Sui, Bitcoin, smart contract integrations, wallet integrations, staking, lending, and secure transaction processing.

Experience: 8 years

Yearly salary: $94,000

Hourly rate: $45

Nationality: 🌏 Remote

Residency: 🌏 Remote

Experience

Backend Team Lead

Mindsync

2021 - 2022

Led backend development for an AI and machine-learning marketplace platform. Key responsibilities and achievements: • Designed and delivered the backend architecture from initial concept to production. • Defined service boundaries, domain models, database architecture, and communication patterns for a new microservice-based platform. • Introduced Domain-Driven Design and established unit, domain, integration, and end-to-end testing practices. • Built asynchronous workflows and distributed services using PostgreSQL, Redis, and RabbitMQ. • Led and mentored backend engineers, coordinated technical delivery, and maintained architecture and code-quality standards. • Collaborated with product and engineering stakeholders to translate business requirements into maintainable technical solutions. Technologies: Node.js, TypeScript, Express, PostgreSQL, Redis, RabbitMQ, Web3, IPFS.

Middle Backend Node.js Developer

OneTwoTrip

2019 - 2019

Worked on backend services for the company’s tour-booking product. Key responsibilities and achievements: • Developed and maintained backend services supporting tour search and booking workflows. • Integrated a new tour provider, implementing provider-specific data mapping and business logic. • Refactored legacy components and improved the structure and maintainability of the existing codebase. • Applied Domain-Driven Design practices in selected areas of the platform. • Implemented new product functionality and expanded unit and domain test coverage. Technologies: Node.js, Express, MongoDB, Riak.

Senior Backend Developer

DPD in Russia

2019 - 2021

Worked on the modernization of a large-scale logistics platform and the migration of core business workflows toward a microservice architecture. Key responsibilities and achievements: • Refactored legacy services and contributed to the migration of core logistics workflows to a microservice architecture. • Designed and implemented backend services and database components for new logistics processes across Node.js and Java ecosystems. • Delivered new business functionality while supporting the stability and performance of high-load logistics operations. • Introduced Domain-Driven Design practices and expanded unit and domain test coverage. • Developed reusable internal npm packages shared across core services, reducing code duplication and standardizing common functionality. • Worked with PostgreSQL and Oracle, designing new data structures and integrating them with existing enterprise systems. Technologies: Node.js, Express, PostgreSQL, Oracle, Redis, RabbitMQ, Java, Spring Boot.

Middle Backend Node.js developer

Delimobil

2018 - 2019

Took ownership of backend development for the company’s core car-sharing platform. Key responsibilities and achievements: • Migrated the company’s core backend platform from an external vendor to an in-house engineering team, completing the production transition within four weeks. • Implemented a significant part of the backend migration scope and subsequently maintained and extended the platform in production. • Delivered new functionality for the core car-sharing product and refactored existing backend components. • Designed the service and database architecture for the B2B product segment. • Built event-driven and real-time data services using Node.js, Redis, RabbitMQ, and Kafka. • Supported production systems responsible for vehicle status, availability, and operational workflows. Technologies: Node.js, Express, Koa, PostgreSQL, MySQL, Redis, RabbitMQ, Kafka.

Junior Backend Node.js developer

Delimobil

2018 - 2018

• Developed a real-time service for receiving, processing, and storing vehicle tracker data. • Built a parking-management service for the Anytime car-sharing platform, handling vehicle status updates and parking availability in production. • Implemented WebSocket-based communication for real-time operational updates. • Worked with PostgreSQL data models and production integrations used by car-sharing services. Technologies: Node.js, Express, Socket.IO, PostgreSQL.

Skills

api

backend

blockchain

cryptography

ethereum

grafana

javascript

mongo

nestjs

nextjs

postgres

rabbitmq

redis

sql

tech-lead

web3js

node

english

russian

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