Senior .NET Developer

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

Company Description

Looking to take your .NET expertise to the next level while working on high-impact FinTech solutions? This role offers the chance to contribute to scalable, cloud-native systems that empower thousands of businesses worldwide.

Company Description

Looking to take your .NET expertise to the next level while working on high-impact FinTech solutions? This role offers the chance to contribute to scalable, cloud-native systems that empower thousands of businesses worldwide.

We’re seeking a Senior .NET Developer to join our team, collaborating with talented engineers, product managers, and designers to deliver innovative financial technology.

At Sigma Software, we work with some of the most forward-thinking companies in the industry. This opportunity will let you grow professionally while making a tangible difference in a fast-paced, regulated environment.

Customer

Our customer is a leading FinTech company providing embedded financing solutions for platforms and marketplaces. Their mission is to enable businesses to offer flexible credit products to customers, helping SMEs access funding quickly and efficiently.

The customer is recognized for innovation in embedded finance, serving thousands of businesses globally and partnering with major platforms. They operate in a regulated environment with a strong focus on scalability, performance, and security.

PROJECT

The project involves enhancing and expanding customer’s embedded finance platform, which integrates directly into partner services to deliver fast, flexible funding to SMEs. You’ll work on a modern tech stack, building features that improve customer and partner experiences while ensuring reliability in production.

Key Technologies: C#, .NET Core, Angular 18, AWS, CI/CD, Docker/Kubernetes, Kafka/RabbitMQ, Datadog, relational & NoSQL databases.

Job Description

• Design, build, and deliver features and projects 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

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

WILL BE A PLUS

• Experience with Docker/Kubernetes
• Familiarity with event-driven architectures (Kafka, RabbitMQ)
• Proficiency with observability tools (Datadog or similar)
• Knowledge of domain-driven design (DDD) and complex domain modeling

Additional Information

PERSONAL PROFILE

• Growth mindset, curiosity, and proactivity
• Strong problem-solving skills balancing complexity and simplicity
• Feedback-oriented, open to giving and receiving constructive input
• Ownership & accountability in delivering commitments
• Team player with strong collaboration skills
• Adaptability to changing priorities
• Excellent communication skills across disciplines