ReByteIT: Microsoft security consulting with personal responsibility
ReByteIT supports small and medium-sized companies with Microsoft Security, Microsoft 365, identities, and technical compliance topics. Sebastian Kerssen is your direct point of contact – from the first assessment through to the agreed next steps.
ReByteIT stands for focused Microsoft security consulting
Microsoft 365 security is not a single product. Identities, access, endpoints, data, and security capabilities all interlock. ReByteIT helps you understand these connections and set sensible priorities.
Looking at Microsoft 365 in context
What matters is how identities, permissions, endpoints, data, and Microsoft capabilities work together in your environment.
Combining security and usability
Protective measures should be effective without making everyday work unnecessarily difficult. Operations and user experience are always considered.
Making recommendations actionable
Risks, dependencies, and next steps are prepared so that decisions can be made on a transparent basis.
Personal consulting with a clear technical focus
Managing Director and direct point of contact
I am Sebastian Kerssen, Managing Director of ReByteIT. My technical focus is on Microsoft Security, Microsoft 365, identities, and technical compliance topics.
It is important to me to structure complex requirements in an understandable way and to derive measures from them that fit the specific environment and the company’s day-to-day work.
Technical focus
The focus is on securing identities and access, protecting endpoints and data, and systematically evaluating existing Microsoft 365 security capabilities. This also includes securely preparing Copilot and agent scenarios where permissions, data access, and governance need to be clarified before rollout.
Experience in the Microsoft ecosystem
I have been working in the Microsoft ecosystem since 2014. My areas of responsibility include leading and delivering projects as well as developing security concepts for mid-sized companies and large enterprise customers.
My professional career includes OEDIV, Wipro, and Atruvia. I currently also work at Microsoft as a Security Cloud Solution Architect.
Over the course of my career, I have supported more than 0 Microsoft 365 environments and carried out more than 0 security reviews.
View profile on LinkedIn →How I work with companies
The starting point is not a product, but your situation. Together we clarify requirements, relevant risks, and the next sensible step.
Understand the situation
Goals, Microsoft environment, constraints, and specific questions are assessed together.
Evaluate risks
Findings are ordered by relevance, dependencies, and need for action.
Plan implementation
Recommendations show which measures make sense first and which prerequisites apply.
Continue the support
On request, ReByteIT can support the technical implementation or further optimization under a separate agreement.
Microsoft security capabilities
A compact overview of the technical focus areas. You will find more detail on the respective service pages.
Microsoft Security Assessments
Systematically review existing Microsoft environments, make risks visible, and prioritize actions.
View Assessment →Entra ID and identities
Evaluate and secure identities, administrator accounts, roles, MFA, and Conditional Access in context.
View Entra ID →Defender and endpoints
Develop Defender capabilities, endpoint protection, and security-relevant configurations sensibly.
View Defender →Purview and compliance
Structure sensitive information, data classification, protection policies, and technical compliance requirements.
View Purview →Microsoft 365, Copilot, and agent governance
Prepare Copilot and agent scenarios with identities, permissions, data access, and governance in mind.
View Agent 365 →CSP and licensing guidance
Understand licenses and security capabilities clearly, so that technical needs and operations fit together.
View CSP →Microsoft certifications
Current certifications document the technical focus on architecture, security, information protection, and cloud solutions.
A transparent way of working instead of big promises
Trust is built through technical focus, clear responsibilities, and understandable recommendations – not through the largest possible project numbers.
Your benefits in working with us
One point of contact
Goals, questions, and decisions do not pass through changing responsibilities.
Understandable explanations
Technical findings are explained so that decision-makers can follow them too.
Fitting recommendations
Measures are based on your situation, your requirements, and the agreed objective.
Clear boundaries
You can see transparently what analysis, implementation, and ongoing support each include.
Remote or on site
Collaboration is flexible from Münster and throughout Germany.
Who this collaboration is suited to
Let us assess your situation together
In a free and non-binding initial consultation, we clarify which Microsoft 365, security, or compliance topics are relevant for your company and which next step makes sense.