Senior Infrastructure Engineer

Senior Infrastructure / Application Migration Engineer

£600–£700 per day | Inside IR35 | 6+ months | London | 3 days per week onsite

We are looking for a Senior Infrastructure Engineer to support a large-scale merger programme, helping assess and plan the migration of a portfolio of enterprise applications into a new environment.

This is a hands-on technical role focused on understanding how applications are currently configured and determining the best way to migrate them, particularly around identity, permissions, authentication and infrastructure.

Key responsibilities

• Assess applications and determine the appropriate migration approach
• Review Entra ID, Active Directory, SSO, permissions and authentication requirements
• Understand application dependencies across SQL Server, IIS, SharePoint, DNS and certificates
• Assess existing integrations and determine how these should be migrated or reconfigured
• Define changes required to permissions, service accounts, groups and access models
• Work with application owners, infrastructure, identity, security and vendors to agree migration plans
• Provide technical input into current-state/target-state designs, testing and cutover

What we're looking for

A strong Senior Infrastructure Engineer with experience across:

• Entra ID / Active Directory
• SSO – SAML, OAuth and/or OpenID Connect
• Application permissions and access control
• SQL Server
• IIS / web application infrastructure
• SharePoint
• DNS, certificates and application integrations
• PowerShell / scripting

Experience working on application migrations, M&A or large-scale infrastructure transformation programmes is highly beneficial.

The key requirement is someone who can look at an application, understand its identity, permissions, infrastructure and integration dependencies, and determine the best way to migrate it into the target environment.