Senior Software Engineer .NET C#

Rydoo Inc.; Warszawa; On-site; PLN 210,792 - 295,109; Full time

Benefits offered by this job

Competitive salary and benefits

€1000/year learning and development budget

Flexible work policy

International mobility program

Upskilling through training programs

Regular company events

Spectacular onboarding program

Job summary

A leading financial technology firm in Warsaw is seeking a Software Engineer to design backend systems that enhance expense management efficiency for users worldwide. This role involves working in a cross-functional team to improve features and drive innovation. Candidates should have solid experience in backend development, excellent knowledge in .NET and C#, and a degree in computer science or a related field. Enjoy a competitive package, flexible work environment, and opportunities for professional growth.

Qualifications

• Several years of experience with backend development.
• Good knowledge of Entity Framework, SQL Server or similar.
• A team player with a passion for writing clean and testable code.

Responsibilities

• Design backend systems for expense management.
• Work in a cross‑functional team focused on user efficiency.
• Improve pre‑filling and automate hotel itemization.

Skills

.NET

C#

Entity Framework

SQL Server

Service Oriented Architecture

Azure Cloud

Agile

DevOps

LLMs

Angular

Education

Degree in Computer Sciences or related field

Job description

At Rydoo, we make expense management simple, so people can focus on the important work, not their receipts. More than one million users trust us to submit, approve, and control expenses faster and smarter.

Semine shares that same mission. Since 2015, the team has been building AI technology that removes the repetitive, time‑consuming parts of accounting, helping finance teams work smarter.

In July 2025, Semine joined forces with Rydoo to shape the future of financial automation. Together, we’re creating a complete, AI‑powered platform that simplifies accounts payable and expense management, helping businesses run simpler, faster and smarter financial operations.

We’re a global team of +200 people who believe great tech should make life easier. If you have big ideas and want to build something that actually helps people, you’ll fit right in.

Rydoo in a snapshot

• Ambitious international team
• 33 nationalities speaking over 15 languages
• 6 hubs across 3 continents
• Easy‑to‑use spend management app available on iPhone and Android
• Supporting over 10,000+ clients and 1 million+ users worldwide
• 4.6 employer score on Glassdoor>
• Hybrid work policy

The Role

At Rydoo, we build smart, simple solutions that help people spend less time on expenses and more on what matters. As a Software Engineer in our G6 squad, you’ll shape the core of our product — designing backend systems that make expense management faster and smarter for thousands of users worldwide.

You’ll work in a cross‑functional, autonomous team focused on saving time for our end users. From improving pre‑filling and automating hotel itemisation to exploring AI‑powered features, your work will directly influence how companies experience automation every day.

AI is reshaping expectations, and G6 is leading that charge. This mission is just the starting point — as the squad grows, you’ll refine it together to maximise alignment, innovation and impact.

• Several years of experience with backend development.
• Excellent knowledge of .NET, C#.
• Good knowledge of Entity Framework (or any ORM like NHibernate), SQL Server or similar.
• A team player with a passion for writing clean and testable code within a cross‑functional team.
• Experience in optimising the performance and scalability of applications to support our ever‑growing user base.
• Experience with Service Oriented Architecture using Service Bus to connect everything is a plus.
• Knowledge of Azure Cloud (or AWS, GCP) is a plus.
• Agile and DevOps experience is a plus.
• Experience with LLMs is a plus.
• Ability to stay up‑to‑date with industry trends, best practices, and emerging technologies to continuously improve our development processes and drive innovation.
• If you would want to contribute as a Full Stack engineer, knowledge of Angular would be a plus, but it is not necessary.
• A degree in computer sciences or a related field is preferred, but any equivalent experience is just as valuable.

Next to our amazing team, informal & international company culture and our mission to become the number 1 spend and invoice management platform in Europe, we offer some nice benefits that make working at Rydoo / Semine even more fun:

• A competitive package, including salary and benefits
• €1000 / year learning and development budget
• Rydoo Hybrid Work Policy: flexibility to work from home while also fostering team collaboration in our Warsaw hub 1x a week.
• Rydoo On Tour: our international mobility program that gives employees the possibility to temporarily relocate to one of the countries we have a Rydoo office.
• Professional freedom and a flexible work environment
• Upskilling through training and coaching programs
• Regular company and team events
• Wonderful international team with more than 33 different nationalities
• Spectacular onboarding program for all new Rydooer’s
• Permanent contract

Why Join Us

At Rydoo / Semine, we celebrate diversity and are committed to creating an inclusive environment for all employees. We value and encourage ongoing learning opportunities and career progression.

Even if you don't tick every box but see yourself contributing, we encourage you to apply. We're more interested in finding a well‑rounded individual with a can‑do attitude. Your passion, dedication and desire to learn are what matter most to us.

Check us out

LinkedIn: https://www.linkedin.com/company/rydoo

Glassdoor: http://bit.ly/2UujjWJ

Instagram: https://www.instagram.com/rydoo/

YouTube: https://www.youtube.com/channel/UCTZYj7vm_ZcsGFL18jWHt_A