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# Senior Software Engineer (Web & Cloud)

- **Company:** Certara
- **Location:** Sheffield, UK
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** ASP.NET, HTML, JavaScript (Programming Language), .NET Framework, Application Programming Interfaces (APIs), Amazon Web Services, Automation of Tests, Microsoft Azure, C Sharp (Programming Language), Cascading Style Sheets (CSS), Software as a Service, Cloud Computing, Cloud Engineering, Code Review, Databases, Cursor, DevOps, Amazon DynamoDB, Entity Framework, Design of User Interfaces, PostgreSQL, Microsoft SQL Server, MongoDB, NoSQL, Nunit, Mockito, SQLite, SQL Databases, TypeScript, Web Applications, Postman, ReactJS, Delivery Pipeline, AWS Lambda, Cloudformation, Xunit, Event Driven Architecture, Material UI, Kubernetes, Cosmos DB, Graphql, Front End Software Development, Claude, Api Design, Restful APIs, Amazon Simple Queue Service (SQS), Terraform, Webhooks, Serverless Computing, Jasmine, Azure Resource Manager
- **Published:** October 23, 2026
- **Apply:** https://www.indeed.com/viewjob?jk=187f60aeb8049679

## About the Role

Essential

 * .NET and C#: extensive proficiency in .NET, C# and ASP.NET, with a strong track record of delivering complex web solutions.
 * Distributed cloud architecture: designing and building distributed, event-driven cloud architectures on AWS or Azure, using container orchestration (e.g. Kubernetes) and/or cloud-native serverless tools (e.g. AWS Lambda, SQS/SNS, or Azure Functions, Service Bus, Event Grid).
 * Databases and ORMs: proven experience with SQL databases (e.g. SQL Server, PostgreSQL, SQLite) and/or NoSQL databases (e.g. MongoDB, AWS DynamoDB, Azure Cosmos), and .NET ORMs (e.g. Entity Framework, Dapper).
 * API development: advanced understanding of good-practice API development, integration and testing (e.g. RESTful services, GraphQL), with security, performance and scalability in a SaaS or public-cloud-facing system.
 * Automated testing: strong expertise writing and maintaining automated tests (e.g. unit, integration or component tests using NUnit, xUnit, Jest or Jasmine).
 * Front-end competence: capable across the front end, building and integrating UI components with React and TypeScript to a solid, functional standard (you'll be a competent consumer of our UI design system, not a CSS/visual-design specialist).
 * AI-assisted development: fluency with AI-assisted development tools (e.g. Cursor, Claude) as part of everyday engineering, using them to design, write and review code well.
 * Communication and judgement: excellent communication and leadership skills in a collaborative team, with strong problem-solving, sound architectural judgement and attention to detail.

Desired

 * Experience of Infrastructure as Code (e.g. Terraform, AWS CloudFormation, Azure Resource Manager).
 * Experience relating front-end work to API consumption good practices such as schema validation, or event-driven architectures (e.g. webhooks).
 * Deeper front-end and modern web expertise (e.g. JavaScript, HTML, CSS, component libraries, design systems) beyond functional competence.
 * In-depth understanding of CI/CD pipelines and DevOps practices, particularly in Azure.
 * Extensive experience with automated testing frameworks for APIs (e.g. Postman, NUnit).
 * Expertise with external dependency mocking tools (e.g. TestContainers, Wiremock).
 * Prior experience mentoring developers or leading technical initiatives.

## Description

* Lead the design, development, testing, and deployment of cloud-native, scalable, high-performance solutions and platforms, including web applications, APIs, services, databases, event buses and other infrastructure.
 * Provide collaborative expertise and consultancy on distributed event-driven cloud architecture good practices.
 * Partner with internal stakeholders to define, analyse, and architect technical solutions that meet complex requirements.
 * Diagnose and resolve advanced issues related to functionality, performance, scalability, and user experience.
 * Collaborate with the DevOps team to design and optimize deployment pipelines and maintain robust cloud-hosted solutions.
 * Oversee the integration of APIs and third-party services, ensuring seamless functionality and performance.
 * Drive the development and maintenance of automated tests for APIs to guarantee reliability and efficiency.
 * Provide expert technical support and mentorship to internal teams, customers, and junior developers.
 * Enhance and maintain existing applications, implementing improvements in performance, reliability, and scalability.
 * Enforce security best practices and ensure applications meet stringent protection standards.
 * Proactively stay ahead of development trends, frameworks, and emerging technologies, recommending innovative solutions.