.NET Backend Engineer - Cloud, AI & AWS (Hybrid, Krakow)

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

Job summary

Cornerstone Research is seeking a Software Engineer with 1–2 years of professional experience to design, build, and maintain cloud-native backend services in C#/.NET Core, deployed on AWS. You will also contribute to frontend work in React or Angular and integrate AI-enabled features into production systems.

The role emphasizes delivering well-structured APIs, robust data access via SQL Server, and collaborating across teams to ensure reliable, scalable software.

Qualifications

• 1–2 years of professional software development experience building applications in C#/.NET.
• Demonstrated experience designing and consuming RESTful APIs.
• Strong SQL skills against SQL Server: data modeling, joins, stored procedures, indexing, and query optimization.
• Hands-on experience deploying or operating workloads on AWS.
• Solid grasp of object-oriented design, SOLID principles, and common design patterns.
• Working experience with a modern front-end framework such as React or Angular, plus HTML/CSS/JS basics.

Responsibilities

• Design, develop, and maintain backend services and RESTful APIs in C# / .NET Core, deployed on AWS.
• Write, review, and optimize SQL — queries, stored procedures, views, and schema changes.
• Build and deploy cloud-native components on AWS using Lambda, ECS/Fargate, API Gateway, S3, RDS, and CloudWatch.
• Develop front-end features using React or Angular and integrate with backend APIs.
• Own delivery of assigned features end to end: design input, implementation, tests, review, deployment via CI/CD.
• Monitor, debug, and improve application performance, security, and reliability.
• Investigate issues, perform root cause analysis, implement durable fixes.
• Participate in agile ceremonies, contribute to estimations and design reviews.
• Develop and integrate AI-powered features using AWS Bedrock and LLM frameworks.
• Collaborate with QA, product, operations, IT security, and release management.

Skills

C#/.NET

REST APIs

SQL Server

AWS

React/Angular

Git workflows

Unit testing

Secure coding

Design patterns

AI basics

JavaScript/TypeScript

HTML/CSS

Education

Bachelor's degree in CS or related

Tools

AWS Lambda

S3

ECS/Fargate

API Gateway

RDS

DynamoDB

SQS/SNS

CloudFormation/CDK/Terraform

Job description

Cornerstone Research is seeking a Software Engineer with 1–2 years of professional experience to design, build, and maintain cloud-native backend services in C#/.NET Core, deployed on AWS. You will also contribute to frontend work in React or Angular and integrate AI-enabled features into production systems.

The role emphasizes delivering well-structured APIs, robust data access via SQL Server, and collaborating across teams to ensure reliable, scalable software.