Senior Software Engineer (.NET)

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

Job summary

BlackLine is hiring for an early shaper of our Krakow Engineering Hub. You will build and ship high-impact features for a market-leading AI-powered Invoice-to-Cash platform, using Cursor and Claude to accelerate development.

Join a fast-moving team that values quality, performance, and enterprise-scale security. You will mentor teammates, influence the technical roadmap, and help define the engineering culture in Krakow.

Qualifications

• Strong experience building production-grade SaaS apps.
• Proficiency in C# and software architecture.
• Experience with AI-assisted development tools (Cursor, Claude).
• Familiarity with CI/CD, automated testing, and infrastructure-as-code.
• Knowledge of cloud-native architectures.
• Experience in regulated industries such as finance.

Responsibilities

• Build and ship high-impact features from concept to production.
• Embrace AI-accelerated development using Cursor and Claude.
• Drive technical design for scalable, maintainable SaaS core.
• Collaborate with product, design, and engineers on roadmaps.
• Engineer for enterprise scale focusing on performance and security.
• Mentor teammates and promote best practices via reviews.

Skills

C# expertise

SaaS architecture

CI/CD & automated testing

Observability & tracing

Regulated industry experience

Tools

Cursor

Claude

AWS

Azure

GCP

Job description

It's fun to work in a company where people truly believe in what they're doing! At BlackLine, we're committed to bringing passion and customer focus to the business of enterprise applications.

Since being founded in 2001, BlackLine has become a leading provider of cloud software that automates and controls the entire financial close process. Our vision is to modernize the finance and accounting function to enable greater operational effectiveness and agility, and we are committed to delivering innovative solutions and services to empower accounting and finance leaders around the world to achieve Modern Finance.

Being a best-in-class SaaS company, we understand that bringing in new ideas and innovative technology is mission critical. At BlackLine we are always working with new, cutting-edge technology that encourages our teams to learn something new and expand their creativity and technical skillset that will accelerate their careers.

This role is specifically for our AI-powered Invoice-to-Cash (I2C) solution, a market-leading platform that uses intelligent automation to help companies collect cash faster, unlock working capital, and supercharge efficiency in their accounts receivable processes.

Work, Play and Grow at BlackLine!

As one of the founding engineers of our new Engineering Hub in Krakow, you are joining at a moment that rarely comes twice in a career. You will be an early shaper of this hub's engineering culture, setting standards, mentoring future teammates, and leaving a mark on a product used by finance teams across the globe.

You will bring strong hands‑on engineering skills and a growth mindset to a team that moves fast and takes quality seriously. In our mission to deliver autonomous finance, you will leverage modern AI development tools like Claude and Cursor as force multipliers, shipping high‑impact features on a mission‑critical enterprise platform.

You'll Get To

• Build and Ship High-Impact Features: Take full ownership of complex features from concept to production, writing clean, performant, and well-tested code for a mission‑critical enterprise application.
• Embrace AI-Accelerated Development: Utilize agentic development tools (e.g., Cursor, Claude) to radically accelerate the design, coding, and testing lifecycle for your team.
• Drive Technical Design: Design and implement scalable, robust, and maintainable solutions for our core SaaS platform, ensuring the long‑term health of our codebase.
• Collaborate and Influence: Partner closely with product managers, designers, and other engineers to refine requirements, contribute to the technical roadmap, and deliver exceptional value to our customers.
• Engineer for Enterprise Scale: Ensure our systems are built with a relentless focus on performance, reliability, and security to meet the demands of a global user base.
• Mentor and Elevate: Act as a technical leader and mentor within the team, elevating the engineering bar through code reviews, knowledge sharing, and establishing best practices

Technical/Specialized Knowledge, Skills, and Abilities

• Demonstrated expertise in using AI-driven development tools (e.g., Cursor, Claude) to significantly improve software engineering velocity and quality
• Strong experience designing, building, and deploying production‑grade, scalable, and secure SaaS applications.
• Proficiency in C# is required, with a deep understanding of software architecture, data structures, and algorithms.
• A proven track record of driving complex projects from ambiguous requirements to successful launch.
• A strong foundation in modern software development practices, including CI/CD, automated testing, and infrastructure-as-code.
• A strong observability mindset - logging, metrics, and distributed tracing across microservices.
• Proven ability to translate complex business problems into simple, elegant technical solutions.
• Experience building software in a regulated industry, such as finance or accounting.
• Knowledge of cloud-native technologies and experience building applications on platforms like AWS, Azure, or Google Cloud.
• Familiarity with the principles of Responsible AI and how to apply them in a software development context.