Senior Software Engineer (C# / .NET Core)

Wetelo is a software development company building custom SaaS products since 2010. We partner with startups and growing businesses to design and develop scalable, business-driven products, taking full ownership from idea to long-term support.

We are looking for a Senior Back-End Engineer (C# / .NET Core) to join a long-term fintech platform in the investment management domain.

Domain: FinTech / Investment Management

Experience: 5+ years

Project Overview
You will work on a financial platform that manages investment data, portfolio operations, and automated financial workflows. The platform consists of REST APIs and batch (command-line) applications.

Tech Stack
— C# / .NET Core
— SQL (relational databases)
— MongoDB, Firestore (or other NoSQL DB)
— REST API development
— Batch / background processing
— Cloud platforms (AWS / Azure / GCP)
— CI/CD pipelines
— Distributed systems concepts

Responsibilities
— Design and implement backend features and services in .NET Core
— Maintain and evolve the existing fintech platform
— Take ownership of backend components from design to production deployment
— Develop and extend REST APIs used by internal and external systems
— Implement integrations with brokers, payment providers, and third-party services
— Write high-quality, scalable, and fault-tolerant code
— Improve performance, reliability, and maintainability
— Troubleshoot and support production systems
— Participate in technical discussions and architectural decisions as a senior contributor
— Review code and collaborate closely with other senior engineers
— Contribute to CI/CD and cloud infrastructure improvements when relevant

Requirements
— 5+ years of backend development experience
— Strong experience with C# / .NET Core
— Strong experience with SQL (including performance optimization)
— Experience with MongoDB and/or other NoSQL databases
— Strong experience designing and implementing REST APIs
— Experience developing and operating applications in cloud environments (AWS, Azure, or GCP)
— Experience running and maintaining production systems
— Solid understanding of distributed systems and background processing
— Ability to work autonomously in a senior, flat team structure
— Good English (B2+)

Nice to Have
— Experience with CI/CD pipelines and Kubernetes
— Experience with event-driven systems (RabbitMQ or similar)
— Experience in financial services / investment platforms (non-crypto)
— Understanding of portfolio logic or financial data flows
— Experience with scalable, high-load systems

What We Offer
— Supportive and comfortable working environment
— Free online speaking club to practice English
— Training and self-development opportunities
— Team-building events and corporate parties
— Social security package and additional perks

Hiring Process
Pre-screen interview with a Recruiter → Technical interview → Interview with the client→ References → Job Offer