Senior Software Engineer

Wallex is a FinTech company providing a secure cryptocurrency exchange platform and digital asset payment solutions.
With a vision to become a leading global FinTech enterprise, Wallex is recognized as one of the largest cryptocurrency exchange platforms in Iran, supporting the online trading of over 130 cryptocurrencies.

We are looking for a Senior Software Engineer with strong experience in Python or Go, Apache Kafka, distributed systems, and event-driven architecture to join our Market Making engineering team.

You will design, build, and operate reliable, high-throughput backend systems that process real-time market data, trading events, orders, executions, positions, and risk-related information.

This role goes beyond application development. You will contribute to system architecture, technical design, scalability, reliability, observability, and production engineering across the market-making platform.

You will work closely with software engineers, DevOps/SRE engineers, and product stakeholders to build systems that remain correct and predictable under high throughput, network failures, duplicated events, exchange disruptions, and rapidly changing market conditions.

Responsibilities

• Design, develop, and maintain high-performance backend services using Python or Go.
• Design and evolve event-driven and distributed system architectures.
• Build and operate high-throughput event-processing pipelines using Apache Kafka.
• Design Kafka topics, partitions, consumer groups, message schemas, and event contracts.
• Integrate with external exchanges through REST APIs, WebSockets, and streaming interfaces.
• Design reliable event-processing workflows with clear guarantees around:
• • Message ordering
  • Idempotency
  • Duplicate processing
  • Retry behavior
  • Offset management
  • Failure recovery
  • Event replay
• Build asynchronous and concurrent systems for real-time workloads.
• Identify and resolve race conditions, concurrency issues, and distributed-state inconsistencies.
• Improve system throughput, latency, resilience, and resource efficiency.
• Implement appropriate retry strategies, dead-letter handling, backpressure, timeouts, and circuit breakers.
• Design state-reconciliation mechanisms between internal systems and external exchanges.
• Build services that recover safely from process crashes, exchange disconnects, and infrastructure failures.
• Develop and maintain APIs and internal service contracts.
• Design and optimize data access using relational and analytical databases.
• Use Redis or similar technologies for low-latency state management and caching.
• Build production observability using:
• • Metrics
  • Distributed tracing
  • Structured logging
  • Dashboards
  • Alerting
• Monitor and troubleshoot Kafka consumer lag, exchange connectivity, system latency, resource bottlenecks, and production incidents.
• Write high-quality unit, integration, contract, and end-to-end tests.
• Participate in architecture reviews and technical design discussions.
• Perform code reviews and contribute to engineering standards and best practices.
• Mentor engineers and help improve the technical quality of the team.

Required Qualifications

• 5+ years of professional software engineering experience.
• Strong production experience with Python or Go.
• Strong knowledge of backend architecture and system design.
• Hands-on production experience with Apache Kafka.
• Strong understanding of Kafka concepts such as:
• • Topics and partitions
  • Consumer groups
  • Offset management
  • Message ordering
  • Delivery semantics
  • Consumer rebalancing
  • Consumer lag
• Strong understanding of event-driven architecture and distributed systems.
• Experience designing idempotent and fault-tolerant services.
• Strong understanding of concurrency, race conditions, and asynchronous processing.
• Experience working with REST APIs and WebSockets.
• Strong experience with PostgreSQL, MySQL, or similar relational databases.
• Experience with Redis or similar in-memory data stores.
• Solid understanding of transactions, consistency, concurrency, and distributed state.
• Strong understanding of failure handling and recovery in distributed systems.
• Experience with containerized applications and familiarity with Kubernetes or similar orchestration platforms.
• Experience building observable production systems.
• Strong debugging and production troubleshooting skills.
• Strong knowledge of software testing principles and automated testing.
• We build, not watch — This is where you belong!