Lead Backend Engineer — Growth(Java + Go)

ABFinance is a US-based firm building digital finance for the future. Our vision is to create a full financial ecosystem where digital assets, traditional finance, and everyday money management live in one seamless experience that is made available to everyone. Founded by a team of innovators, traders, and compliance professionals, our mission is to bring digital assets to the mainstream through secure, regulated products. Our flagship ecosystem combines a compliant, security-first crypto exchange serving both retail and institutional clients, alongside a Debit Card that enables everyday spending and smooth bridging between fiat and digital assets, supported by core capabilities such as spot trading and yield generation products. Role Overview Responsible for architecture design and development of growth business systems including affiliate systems, rebate engines, VIP services, and marketing campaigns, covering both B2B and B2C growth scenarios. Responsibilities • Design, develop, and optimize affiliate systems (commission management, referral relationships, campaign management, BD Portal); • Build and maintain rebate engines, VIP service tiers, and marketing campaign systems; • Develop core modules of B2B systems including merchant management and institutional onboarding; • Analyze system bottlenecks, resolve complex issues, and perform performance tuning. Requirements • Bachelor's degree or above in Computer Science or a related field; • 5+ years of backend development experience; proficient in at least one of Java or Golang, dual-language experience preferred; • Expert-level proficiency in at least one mainstream framework (Spring Boot / Spring Cloud or Go Gin); • Proficient in gRPC/HTTP API development with solid understanding of concurrency and experience with high-concurrency systems; • Familiar with distributed systems; proficient in Kafka, gRPC and other mainstream middleware, with understanding of underlying principles; • Hands-on experience with Claude Code for AI-driven development; • Strong logical thinking and business comprehension skills; good coding habits with clear structure and naming conventions; • Docker and Kubernetes experience preferred. Nice-to-Haves • Experience developing affiliate/referral or rebate systems at a crypto exchange; • Telegram Bot or social platform integration experience.