Senior Software Developer

If you're passionate about coding and eager to tackle exciting challenges, this is the opportunity for you. As a Senior Software Developer, you'll lead the charge on our most innovative product development, collaborating with a talented team to bring game-changing ideas to life.

Forget the corporate jargon - we're all about getting things done and making a difference. If you're ready to roll up your sleeves, we want to hear from you. Let's build the future together.

TellJO is a for-profit, mission-driven company proactively supporting people susceptible to vulnerability. TellJO puts purpose before profit and believes in a fair and equal society for all.

Working for a startup is not easy. TellJO is seeking an individual who wants to have a tangible impact on our business and has the courage and determination to drive the product development forward at pace.

Role and Responsibilities

What You'll Do

· Design, develop, and maintain applications using C#, .NET, React, and TypeScript

· Own and improve our Azure-hosted SaaS platform

· Manage deployment pipelines and release processes using Azure DevOps

· Ensure the platform remains secure, reliable, scalable, and performant

· Manage Cloudflare WAF, Microsoft Defender for Cloud, and security monitoring

· Apply secure-by-design principles throughout the software development lifecycle

· Support ISO 27001 and Cyber Essentials compliance activities

· Troubleshoot issues across application, infrastructure, and security layers

· Contribute to product direction, technical architecture, and continuous improvement

· Use modern AI-assisted development tools to improve productivity and code quality

Essential Skills & ExperienceSecurity & Platform

Do you have experience in Software development?, · Strong understanding of OWASP Top 10 and secure software development practices

· Experience with Cloudflare WAF and web application security

· Experience with Microsoft Defender for Cloud (Azure Defender)

· Experience identifying, prioritising, and remediating security vulnerabilities

· Strong understanding of authentication, authorisation, MFA, and least-privilege access principles

Microsoft Azure

· Experience managing Azure-hosted applications and services

· Experience with Azure App Services, Azure SQL, Key Vault, Blob Storage, and monitoring tools

· Experience with Azure DevOps and CI/CD pipelines

· Understanding of cloud security, resilience, and operational best practices

Software Engineering

· Strong commercial experience with C# and modern .NET

· Strong React and TypeScript experience

· Experience with Entity Framework Core and SQL Server

· Experience building and maintaining REST APIs

· Experience designing scalable and maintainable software solutions

· Strong debugging, troubleshooting, and problem-solving skills

Working Style

· Comfortable operating independently and taking ownership

· Able to balance strategic thinking with hands-on delivery

· Strong communication skills and a pragmatic approach to problem solving

Desirable Skills

· ASP.NET Core MVC

· Microsoft Entra ID / Azure AD

· ISO 27001 or Cyber Essentials

· WordPress

· SaaS platform experience

· Experience working within regulated or security-conscious environments