.NET Backend Engineer

• Senior-level experience building and maintaining production systems with.NET.

• Hands-on experience with.NET Framework (not only.NET Core /.NET 6+).

• Strong understanding of Windows Service lifecycles, installation, startup behavior, and recovery options

• Proficiency in using and integrating dynamic link libraries (DLLs) to interface with other Windows software

• Experience with Windows Installer (MSI/WiX/Inno Setup)

• Familiarity with inter-process communication (IPC) techniques

• Understanding of system-level Windows APIs

• Strong understanding of relational databases and transactional systems.

• Proven ability to work with legacy or constrained systems responsibly.

• Calm, methodical approach to debugging and problem solving. Comfortable working autonomously with high ownership.

• Professional level Spanish, and English (B1 should be enough).

• Above all, you're a reliable and trustworthy person

• Experience owning systems that are business-critical.

• Experience in financial, accounting, or regulated domains.

• Experience modernizing or stabilizing legacy systems.

• Exposure to system integration or migration projects.

Our goal is to become the go-to Financial Operating System for accounting firms and SMEs in Southern Europe, unifying accounting, tax, payments, planning, and banking into a single platform. We are currently a tight-knit team of 50+ people and plan to grow in 2026, with a strong focus on engineering, product design, and sales.

Today, Kabilio already runs three core products in production - Invoices Processing, Bank Transactions, and Invoicing - used daily by real customers. At the same time, we're building our Accounting platform, the product that defines our long-term vision and the reason Kabilio was founded. AI sits at the core of everything we build, from automating and categorizing financial data to enabling intelligent workflows and decision-making across the entire financial lifecycle. We rely on modern architectures and proven technologies to turn this vision into a scalable, production-ready platform.

As a Senior.NET Engineer at Kabilio, you will take ownership of a core backend system that is critical to the company and our customers. This system operates independently from our main platform and supports key business workflows under strict client and regulatory constraints.

Due to customer and compatibility requirements, this system is built on.NET Framework 4.8 and relies on mature, well-established libraries. This role requires strong engineering judgment, deep experience, and a pragmatic approach to maintaining and evolving software in real-world constraints. While the platform is constrained by customer requirements, there is room to improve internal structure, reliability, and tooling over time.

• Take technical ownership of a core, isolated.NET system used in production.

• Maintain, extend, and stabilize an existing codebase built on.NET Framework 4.8.

• Ensure reliability, performance, and correctness in a business-critical environment.

• Diagnose and resolve complex production issues.

• Collaborate with other engineering teams to ensure correct integration points.

• Make pragmatic decisions balancing risk, maintainability, and business needs.

• Gradually improve code quality and internal structure where possible.