Backend Developer with experience in C#/.NET (On-site)

Description

**Location:** El Prat de Llobregat, Barcelona (on-site position – no remote work option) We are an innovative company transforming the digital development landscape. We are looking for a **Backend Developer**, *Mid-level or Senior*, with experience in **C# and .NET**, to join our team. If you are passionate about building robust architectures, efficient APIs, and scalable solutions, this role is for you. Ideal for candidates with **minimum 2 years of experience**. Responsibilities * **Design and develop secure, efficient, and well-structured REST APIs**. * Work with **C# and .NET** in modern and scalable environments. * Manage **PostgreSQL** databases, optimizing queries and structures. * Use **Entity Framework / EF Core** for data management. * Collaborate on projects using **Blazor**, or learn this technology for new developments. * Integrate external services, including **payment gateways and third-party providers**. * Incorporate **AI tools applied to development** (Copilot, Claude, Codex, etc.). * Validate, review, and improve AI-generated code before integrating it into the project. * Participate in **CI/CD pipelines** for efficient deployments. * Collaborate with frontend, product, and QA teams. Requirements * **Minimum 2 years of experience** in Backend development with **C# and .NET**. * Experience with **REST APIs** (design, development, and consumption). * Solid knowledge of **PostgreSQL**. * Proficiency with **Entity Framework / EF Core**. * Knowledge of **Blazor**, or willingness to learn it. * Experience integrating **third-party services** and **payment gateways**. * Use of **AI tools for development** (Copilot, Claude, Codex, etc.). * Ability to **analyze, validate, and improve** AI-generated code. * Interest in staying updated on new tools and best practices for AI-assisted development. * Experience with **JIRA** and agile methodologies. * Knowledge of **CI/CD** and tools such as Bitbucket. * Excellent communication and problem-solving skills. * Spanish required. Benefits Opportunity to grow within innovative digital projects. Access to training and professional development. Pet-friendly environment. Working hours: Monday–Thursday 8:30–16:30, Friday 8:30–15:00. Sweets, fruits, and coffee available in the office. Conditions * Employment type: Full-time, on-site. Send your CV to info@onliners.es Work location: On-site employment