
Lead / Senior Backend Developer (Go / Java)
Full Time
Remote
Job Description
We are looking for a Lead / Senior Backend Developer to design and build the core architecture of a new P2P payment system, including the financial engine, transaction matching, and escrow logic. You will define the technical foundation of the platform — from microservices/modular monolith architecture to transactional integrity, high-load data handling, and API security — and play a key role in building a payment system from scratch.
About the Client
Our client is building a new P2P payment system from the ground up — a fintech product enabling secure, fast, and scalable peer-to-peer transactions. The company is focused on creating reliable payment infrastructure, combining modern architecture with strong transactional guarantees to serve users at scale.
What You Will Do
-
Design the architecture of a P2P payment platform (microservices or modular monolith).
-
Build and own the financial engine, including transaction processing, payment matching logic, and escrow mechanics.
-
Design and implement robust transactional logic ensuring data consistency and reliability across distributed payment flows (ACID, Saga Pattern).
-
Architect and optimize high-load database solutions (PostgreSQL — sharding, query optimization, indexing strategies) to support growing transaction volumes.
-
Design and implement asynchronous, event-driven communication using message brokers (Apache Kafka / RabbitMQ) for reliable payment processing pipelines.
-
Utilize in-memory data stores (Redis) for caching, session management, and performance-critical operations.
-
Implement and enforce API security best practices (OAuth2, JWT, rate-limiting, fraud detection and prevention mechanisms).
-
Make key architectural decisions on scalability, fault tolerance, and system resilience for a mission-critical payment system.
-
Collaborate with product, DevOps, and QA teams to ensure smooth delivery, compliance, and system stability.
-
Mentor engineers, conduct code reviews, and help establish engineering best practices across the team.
-
Take full ownership of critical backend components, from design through production, in a system handling real money movement.
What We Are Looking For
-
5+ years of commercial development experience in Go or Java/Kotlin.
-
Deep understanding of transactional logic (ACID, Saga Pattern) and distributed systems design, ideally applied to financial or payment systems.
-
Solid experience with high-load databases, especially PostgreSQL (sharding, query optimization, performance tuning).
-
Hands-on experience with message brokers (Apache Kafka / RabbitMQ) and in-memory databases (Redis).
-
Experience implementing API protection mechanisms (OAuth2, JWT, rate-limiting, fraud prevention).
-
Strong understanding of microservices and/or modular monolith architecture patterns.
-
Prior experience building or working on payment systems, wallets, matching engines, escrow logic, or other money-movement infrastructure is a strong plus.
-
Solid grasp of system design principles: scalability, fault tolerance, consistency trade-offs, idempotency in financial transactions.
-
Ability to make and defend architectural decisions, and communicate them clearly to the team.
-
Understanding of payment industry standards, compliance, or regulatory considerations is a plus.
-
Upper-Intermediate English level or higher (written and spoken) is a plus.
-
Prior experience in fintech, banking, or high-load transactional platforms is a plus.
What You Can Expect
-
A rare opportunity to architect a payment system from zero and shape its entire technical foundation.
-
Career growth opportunities with the potential to grow into a Head of Engineering / Tech Lead role.
-
Close collaboration with product and engineering leadership, with real influence over key architectural and business-critical decisions.