Senior Software Engineer (Web & Cloud)

Certara; Sheffield; On-site; GBP 90,000 - 120,000; Full time

Job summary

Certara is building the next generation of cloud-based workflow tools for biopharma, delivering scalable web apps, APIs and services. A Senior Software Engineer will help design, develop, and optimize solutions that enable AI-assisted engineering and reproducible results for complex drug development workflows.

You will work across cloud platforms, mentor peers, and shape technical direction in a fast-paced, collaborative environment with a focus on security, performance and reliability.

Qualifications

• Proven mastery of .NET/C# and ASP.NET for complex web solutions.
• Experience designing distributed, event-driven cloud architectures.
• Strong SQL/NoSQL database and ORM expertise (EF, Dapper).
• Advanced API development with REST/GraphQL and security considerations.
• Extensive automated testing (unit/integration) experience.
• Frontend skills with React/TypeScript within a UI design system.
• Fluency with AI-assisted development tools (Cursor, Claude).
• Excellent communication and architectural judgement in teams.

Responsibilities

• Lead design, development, testing and deployment of cloud-native, scalable solutions.
• Provide consultancy on distributed event-driven cloud architecture best practices.
• Partner with stakeholders to architect technical solutions meeting complex requirements.
• Diagnose and resolve advanced performance, scalability and UX issues.
• Collaborate with DevOps to optimize deployment pipelines and maintain cloud-hosted solutions.
• Oversee API integration and third-party service integrations.
• Drive automated tests for APIs to ensure reliability and efficiency.
• Mentor junior developers and provide technical leadership across teams.
• Improve existing applications for performance, reliability, and security.
• Stay ahead of trends, recommending innovative solutions.

Skills

.NET and C#

Distributed cloud architecture

Databases and ORMs

API development

Automated testing

Front-end competence

AI-assisted development

Communication and judgement

Tools

Terraform

AWS CloudFormation

Azure Resource Manager

Job description

Overview

About Certara

Certara accelerates the potential of bringing medicines to market and to patients using biosimulation software, technology, and services to transform traditional drug discovery and development. Our clients include more than 2,400 biopharmaceutical companies, academic institutions, and regulatory agencies across 70 countries.

Our goal is to enable the life sciences industry’s use of data, modeling, and analytics to make better decisions across the various phases of discovery and drug development. Our software and scientists incorporate modern advances in scientific understanding, drug development experience, data analysis, and AI resulting in significant opportunities to decrease the cost and increase the probability of success for new drug approval and commercialization.

A Senior Software Engineer at Certara, you will lead the design, development, and optimization of cloud-native, scalable web applications, APIs and services. Collaborating with developers, IT, DevOps, and science teams, you’ll drive technical solutions, mentor others, and ensure high-quality deliverables that support our business operations and customer needs in a dynamic, forward-thinking environment.

This is a greenfield opportunity to help build the future of the organisation. Our established desktop products have a long and respected history, but our future is in web, cloud and software-as-a-service, delivered to major pharmaceutical companies and regulators. You’ll help design and build that new platform from the ground up: high-profile work that sits right at the centre of the company’s direction.

AI-assisted engineering is core to how we work. We use tools such as Cursor and Claude every day to design, write and review code, and we expect everyone on the team to be fluent with them and to keep pushing how AI helps us build better software, faster. This is central to the role, not an optional extra.

About the project

We’re building the next generation of cloud-based workflow tools for our Simcyp products, the modelling and simulation software that pharmaceutical companies and regulators rely on to understand how drugs behave in the body long before they reach a patient. Today, modelling teams set up and run that work in many different ways, and results aren’t always easy to reproduce or share. Our goal is to change that: to make sophisticated simulation workflows straightforward to build, share and run reliably at scale, with AI woven through the experience. This is greenfield work, and it’s the future of our business: high-profile, technically ambitious, and genuinely meaningful, because the faster and more reliably our customers can run their science, the sooner they can develop and deliver new medicines.

What you’ll achieve (first 6-12 months)

• Delivered scalable, cloud-native features and services into production, trusted to own them end to end from design through to deployment. Raised the engineering bar around you through strong API and architecture decisions, solid automated testing, and mentoring of other developers. Become a trusted voice on distributed, event-driven cloud architecture, helping shape technical direction beyond your own work. Embedded AI tools (Cursor, Claude) into how you and the team work, demonstrably accelerating delivery without compromising quality.

Responsibilities

• 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 optimise 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.

Qualifications

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.

Certara bases all employment-related decision on merit, taking into consideration qualifications, skills, achievement, and performance. We treat all applicants and employees without regard to personal characteristics such as race, color, ethnicity, religion, sex, sexual orientation, age, nationality, marital status, pregnancy, physical or mental condition, genetic information, military service, or other characteristic protected by law.