Senior Software Developer
Calling All Senior Software Developers!
Ready to make a real impact?
We're on the lookout for a Senior Software Developer to join our dynamic team.
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.
Your Role in Our Mission
As a Senior Software Engineer at TellJO, you’ll lead the design and delivery of robust, secure, and scalable technology that directly improves people’s lives.
This is more than coding — you’ll:
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Architect and build complex, maintainable systems using C#, NET, and React (ASP Net is a plus).
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Set technical standards for clean, testable, and efficient code, using nUnit, Moq, and modern CI/CD pipelines (Azure DevOps).
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Own deployment pipelines, ensuring secure, reliable, and timely releases to Azure.
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Champion security best practices, performance optimizations, and database efficiency — from query tuning to thread management.
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Drive technical excellence, providing mentorship, conducting code reviews, and guiding team members on best practices and modern patterns.
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Collaborate with stakeholders to shape the roadmap, break down complex problems, and deliver high-impact solutions.
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Working from the Lancing office 5 days a week.
What You Bring
You’re an experienced engineer ready to step up, lead by example, and drive meaningful change. You have:
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Extensive experience building full-stack applications, with a strong focus on front-end (React, TypeScript) and modern C# ( NET Core preferred).
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Proven ability to architect, refactor, and migrate legacy solutions ( NET 4.8 experience a plus).
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Solid grounding in unit testing, mocking, CI/CD, and cloud deployments (Azure).
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Deep knowledge of security principles, scalability, and performance tuning in production environments.
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Strong analytical and problem-solving skills — you tackle complex challenges with a pragmatic mindset.
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A passion for mentorship and technical leadership, with experience guiding less-experienced engineers to success.
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A collaborative, proactive attitude — you thrive in cross-functional teams where your expertise shapes products that matter.
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Proficiency and experience using modern LLMs to assist with software development.
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Experience with Entity Framework Core ORM or similar, against MS SQL Server or similar RDBMS, is essential.
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Experience with Wordpress is a bonus.
Why TellJO?
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Purpose-Driven Work - Help vulnerable people avoid crisis and regain control
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Innovative Tech - Work on meaningful, modern software that makes a difference
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Growth & Learning - Be part of a team that supports continuous development
- Proven Results - Be proud of the measurable social impact you help create
- Company
- TellJO
- Location
- Lancing Business Park, Lancing, West Sussex, England, United Kingdom
- Employment Type
- Full-Time
- Salary
- £45,000 - £57,000 per annum
- Posted
- Company
- TellJO
- Location
- Lancing Business Park, Lancing, West Sussex, England, United Kingdom
- Employment Type
- Full-Time
- Salary
- £45,000 - £57,000 per annum
- Posted