Senior .NET Developer - FinTech, Cloud-Native & AWS

Sigma Software; Kraków; On-site; PLN 180,000 - 240,000; Full time

Job summary

Sigma Software is seeking a senior .NET Developer in Kraków to join a FinTech-focused team building cloud-native solutions. You’ll design, implement, and deliver features using C#, .NET Core, and Angular, collaborating with product and design in an Agile setting.

You'll deploy to AWS, monitor services, and contribute to DevOps practices, testing, and performance improvements while ensuring security and reliability in production.

Qualifications

• 5+ years of experience in software development with strong OOP and system design skills.
• Solid hands-on experience with .NET (C#) and Angular.
• Understanding of software testing concepts and practices.
• Expertise in cloud-native and DevOps practices (CI/CD, automation, monitoring).
• Experience with relational and NoSQL databases.
• Knowledge of non-functional requirements (performance, security, availability).
• Proven experience in FinTech, payments, banking, or regulated financial environments.
• Upper-Intermediate English level or higher.

Responsibilities

• Design, build, and deliver features across C#, .NET Core, and Angular stack.
• Write clean, maintainable, and well-tested code (unit/integration/e2e).
• Take ownership of features from requirements breakdown to deployment.
• Deploy and monitor services in AWS cloud-native environments.
• Handle production issues and incidents with accountability.
• Collaborate with Product, Design, and Engineering teams in Agile practices.
• Contribute to continuous improvement of systems and processes.

Skills

OOP & system design

C# / .NET

Angular

Software testing concepts

Cloud-native & DevOps (CI/CD, automate

Relational & NoSQL databases

Performance, security, availability

FinTech domain experience

English (Upper-Intermediate)

Tools

Docker/Kubernetes

Kafka/RabbitMQ

Datadog

Job description

Sigma Software is seeking a senior .NET Developer in Kraków to join a FinTech-focused team building cloud-native solutions. You’ll design, implement, and deliver features using C#, .NET Core, and Angular, collaborating with product and design in an Agile setting.

You'll deploy to AWS, monitor services, and contribute to DevOps practices, testing, and performance improvements while ensuring security and reliability in production.