Software Developer

  • Synergy Resourcing Solutions Limited
  • Chelmsford, Essex
  • Jan 15, 2026
Contractor I.T. & Communications

Job Description

We're looking to engage an experienced Full Stack Developer to deliver a defined package of security and compliance-focused enhancements to our client's web platform.

This is a short-term, well-scoped contract focused on strengthening authentication, auditing, and application security within an existing production system.

The Role
You will be responsible for implementing several targeted improvements to a live ASP.NET MVC application, including:

  • Adding multi-factor authentication (MFA) to user login
  • Implementing step-up verification for sensitive user actions to confirm user presence at the point of authorisation
  • Enhancing audit logging to capture user actions with timestamps
  • Reducing security vulnerabilities by updating legacy libraries and resolving AppCheck warnings
  • Producing clear technical documentation and handing over to the internal team


Tech Stack

  • ASP.NET MVC (.NET Framework 4.8)
  • C#
  • JavaScript, HTML, CSS
  • REST APIs


Required Experience

  • Strong background in authentication and authorisation patterns
  • Experience securing high-risk or regulated user actions (e.g. approvals, authorisations)
  • Comfortable working independently on well-defined enhancements
  • Ability to work within an existing codebase and platform constraints
  • Clear documentation and handover skills


Desirable

  • Experience in regulated environments
  • Familiarity with step-up authentication or electronic signature workflows
  • Pragmatic approach to improving security without large-scale rewrites


For more info, contact Ruben Davis at Synergy