MSSP vs MSP vs MDR: What Each One Does, How They Charge and Which You Need

The short version: An MSP runs your IT day to day. An MSSP runs security tools and monitoring for you. MDR is a narrower service inside that space: analysts watch your endpoint, identity and email alerts and respond to real threats. Most small and mid-sized companies need an MSP with solid security basics first, and add MDR when nobody is watching alerts outside office hours.

This guide is for owners and IT managers who have been told they need "an MSSP" or "MDR" and want to know what that means for their budget and their team. You will leave with a side-by-side comparison, the usual charging methods and decision rules you can apply to your own company.

What are the three, in one line each?

1. MSP (managed service provider): runs your IT operations: service desk, devices, patching, backups, accounts, with some security included. See what is a managed service provider.
2. MSSP (managed security service provider): takes on security functions: managing and monitoring security tools, vulnerability scanning, log review, security reporting.
3. MDR (managed detection and response): a service where analysts triage alerts, investigate and respond to threats on your systems.

The labels overlap in the market. Some MSPs run a security team, some MSSPs sell MDR, and some MDR vendors do not manage your IT at all. Read the scope, not the label.

How do they compare, point by point?

MSP

1. Main job: keep IT working and up to date.
2. What it watches: devices, servers, network, backups, user accounts.
3. Who acts on a problem: the provider's service desk and engineers, usually inside the contracted hours.
4. Security depth: baseline controls such as MFA, patching, endpoint protection and email filtering.
5. Typical charging: per user, per device or a tiered package.
6. Best fit when: you need the whole IT function covered.

MSSP

1. Main job: operate and monitor security controls.
2. What it watches: firewall and security tool logs, vulnerability scan results, sometimes a security information and event management (SIEM) system.
3. Who acts on a problem: varies. Some alert you and stop; others take defined actions. Ask which.
4. Security depth: broad. Often includes scanning, reporting and policy support.
5. Typical charging: per monitored device or log source, per user or a fixed package by service level.
6. Best fit when: you already have IT support and want to add security operations or reporting.

MDR

1. Main job: find and stop active threats.
2. What it watches: alerts from endpoint, identity, email and cloud tools, according to what the service covers.
3. Who acts on a problem: the analysts investigate, then act or guide your team through the response. Check which actions they may take without asking you.
4. Security depth: deep on detection and response, narrow elsewhere. It does not patch your laptops or reset passwords.
5. Typical charging: per user or per endpoint, sometimes with tiers for coverage or hours.
6. Best fit when: you have the tools but nobody to watch and respond to alerts.

As one example of how a vendor describes MDR, Microsoft Learn says Microsoft Defender Experts MDR has analysts manage your incident queue around the clock, triage and investigate incidents on your behalf, and either take action or guide your team through the response. It also says the service augments your security operations centre rather than replacing it, and that it is not an incident response engagement for an active compromise (checked against Microsoft Learn, 28 October 2026). Microsoft also says the service is sold separately from other Defender products, and Plan 2 requires a minimum of 1,500 licensed seats, so it is aimed at larger deployments. Other MDR offers differ, so compare scope in writing.

Which one do you need?

Use these rules in order:

1. You have no outsourced or internal IT team. Start with an MSP that includes security basics. Buying MDR first leaves the devices and accounts unmanaged.
2. You have an MSP, but nobody reads security alerts after hours. Add MDR, or ask the MSP whether it provides alert monitoring and response and what the hours are. See our security operations centre service.
3. You must show regular security reporting, log review or scanning to customers or auditors. Look at an MSSP service, check what your customer contract actually requires, and confirm the specific reports you need are in the scope.
4. You have an internal IT team that runs devices well but lacks security specialists. look at MDR or an MSSP before adding another MSP.
5. You run a small company and the budget is tight. Fix the basics first: MFA, patching, backups, endpoint protection. Our managed IT security services page shows how we package these.

If you are choosing between antivirus, EDR and MDR on the endpoint, read antivirus vs EDR vs MDR.

Questions to ask any of the three

1. Which of my systems are inside the scope, and which are outside?
2. Who sees an alert first, and in what hours?
3. What actions can you take without asking me, and what needs approval?
4. How fast do you respond to a confirmed threat, in writing?
5. What do I receive each month, and can I see a sample?
6. Who owns the security tools and the data, if I leave?
7. How do you pass information to my MSP or internal team?

Common mistakes

1. Buying by label. Two providers with the same label can offer very different scope.
2. Assuming MDR replaces an MSP. It does not manage devices or users.
3. Assuming alerts mean action. A monitoring-only service tells you about a problem; it may not act on it.
4. Overlapping tools. Paying twice for endpoint protection from the MSP and the MDR vendor causes conflicts and cost.
5. No agreed hand-off. When the MDR analyst says "isolate this laptop", someone with authority must be reachable at 3 a.m. Write the contact path down.

How to check it worked

1. Ask for a test alert or a tabletop exercise and see who responds and how long it takes.
2. Compare the first monthly report with the scope you signed.
3. Confirm the named approvers on your side can be reached out of hours.

FAQ

What does MSP stand for, and what does IT mean?

MSP stands for managed service provider. It is a company that runs part or all of your IT under a written scope and service levels.

What are some examples of managed service providers?

They range from general IT providers that run service desks and devices, to security-focused providers, to firms that specialise in one industry. Compare by scope and service levels.

What is MSSP security?

It is the work an MSSP does for you: operating and watching security tools, scanning for weaknesses, reviewing logs and reporting on risk.

What is SIEM, and does an MSSP use it?

SIEM stands for security information and event management. It collects logs from many systems so patterns can be seen in one place. Some MSSPs operate a SIEM for clients; ask whether yours does and who owns the data.

What is the difference between MSSP and MDR?

An MSSP covers a broad set of security operations, often including reporting and scanning. MDR focuses on detecting and responding to active threats. Some providers sell both.

To see how we combine IT support and security under one scope, read about our managed IT security services.