Backend Software Engineer - .NET, AWS & AI Features

Cornerstone Research; Kraków; Hybrid; PLN 121,000 - 193,000; Full time

Job summary

Cornerstone seeks a Software Engineer to join a hybrid Krakow team building cloud-based applications on the .NET stack. You will own features from design to production support, mainly in C#/.NET, with AWS and SQL Server, and contribute to frontend with React or Angular.

The role emphasizes designing robust backend APIs, optimizing queries, and integrating AI-powered capabilities using modern tooling. Collaborative, agile environment with production releases.

Qualifications

• Bachelor's degree or equivalent practical experience.
• 1-2 years of professional software development with C#/.NET.
• RESTful API design and consumption experience.
• Strong SQL skills with SQL Server.
• Hands-on AWS deployment/operations with multiple services.

Responsibilities

• Design, develop, and maintain backend services and RESTful APIs in C#/.NET Core on AWS.
• Write, review, and optimize SQL queries, stored procedures, views, and indexing.
• Build and deploy cloud-native components on AWS (Lambda, ECS/Fargate, API Gateway, S3, RDS).
• Develop frontend features with React or Angular and connect to backend APIs.
• Own delivery of features end-to-end: design, implementation, tests, review, and CI/CD deployment.
• Monitor, debug, and improve performance, security, and reliability; participate in production support.
• Drive root cause analysis and durable fixes.
• Participate in agile ceremonies and design reviews.
• Develop AI-powered features using AWS Bedrock and LLM frameworks.
• Collaborate across QA, product, operations, IT security, and release management.

Skills

C# & .NET

REST APIs

AWS

SQL Server

React/Angular

AI/LLMs

Git workflows

CI/CD

OWASP security

Agile/Scrum

Education

Bachelor's degree

Tools

AWS Lambda

AWS S3

ECS/Fargate

API Gateway

RDS

DynamoDB

SQS/SNS

IAM

Terraform

CloudFormation

Job description

Cornerstone seeks a Software Engineer to join a hybrid Krakow team building cloud-based applications on the .NET stack. You will own features from design to production support, mainly in C#/.NET, with AWS and SQL Server, and contribute to frontend with React or Angular.

The role emphasizes designing robust backend APIs, optimizing queries, and integrating AI-powered capabilities using modern tooling. Collaborative, agile environment with production releases.