Senior Backend Software Engineer

Jobtailor; Warszawa; Hybrid; PLN 240,000 - 360,000; Full time

Job summary

Jobtailor is seeking a senior Go backend engineer to implement scalable micro-services and tune data models for fintech workloads. You will work on AWS, DynamoDB, and PostgreSQL, with a strong emphasis on performance and reliability.

The role involves collaborating with product on roadmaps, reviewing architecture, mentoring colleagues, and contributing to on-call rotations. Warsaw-based with hybrid on-site and remote work options.

Qualifications

• 3+ years backend experience required.
• Strong Go proficiency.
• Cloud-native design, REST APIs, event-driven patterns.

Responsibilities

• Implement and extend micro-services in Go.
• Write unit/integration/API tests and review PRs.
• Tune data models for low latency and high throughput.
• Collaborate with DevOps on CI/CD and observability.
• Participate in on-call rotation in fintech system.
• Lead architecture reviews and manage tech debt.

Skills

Go Programming

Cloud-Native Design

SQL/NoSQL Skills

Performance Optimization

Event-Driven Patterns

Tools

DynamoDB

Postgres

Terraform/CDK

Kafka

AWS

Job description

• Implement new micro-services and extend existing ones in Go
• Help groom user-story requirements and surface performance / scaling concerns early
• Write unit, integration and API tests; review PRs
• Tune data-models in DynamoDB & Postgres for low-latency, high-throughput workloads
• Pair with DevOps on CI/CD and observability improvements
• Participate in on-call rotation while building a highly available fintech system
• Design and drive high-scale, low-latency services (tens of thousands of orders/sec) for senior-level responsibilities
• Lead architecture reviews, challenge assumptions and keep tech debt in check
• Partner with Product on roadmap feasibility and effort sizing
• Mentor less experienced colleagues

Requirements

• 3+ years of professional back-end experience (ideally 1 year+ in Go)
• Solid grasp of cloud-native design (RESTful APIs, event-driven patterns)
• Working SQL and NoSQL skills; know when each shines
• Comfort diagnosing performance bottlenecks in distributed systems
• Ability to work on-site in Warsaw twice a week (Tue & Thu) and remotely otherwise
• Exposure to serverless architectures on AWS
• Experience with Kafka or another high-volume message bus
• Knowledge of automated trading, market data, or FIX/crypto exchanges
• Familiarity with Infrastructure-as-Code (Terraform or CDK)
• Contract B2B / Employment contract

Core Competencies

Demonstrates expertise in implementing and extending micro-services using Go, with a strong focus on cloud-native design and performance optimization in fintech systems. Proficient in mentoring team members and leading architecture reviews while ensuring high availability and scalability.

Highest-signal resume keywords

• Go Programming
• Cloud-Native Design
• SQL and NoSQL Skills
• Performance Optimization
• Infrastructure-as-Code (Terraform or CDK)

Hard Skills

• Micro-Services Implementation
• Unit Testing
• Integration Testing
• API Testing
• Data-Model Tuning
• Performance Bottleneck Diagnosis
• Automated Trading Knowledge
• Event-Driven Patterns
• Serverless Architectures
• High-Volume Message Bus (Kafka)

Soft Skills

• Mentoring
• Collaboration

Industry Keywords

• Fintech
• Market Data
• FIX Protocol
• Crypto Exchanges
• B2B Contracting

Tools & Technologies

• DynamoDB
• Postgres
• CI/CD
• Observability Tools
• AWS