What is SaaS?

In short

SaaS (software as a service) is software you use over the internet on a subscription basis, while the supplier hosts, maintains and updates it. You install nothing on your own servers and usually pay per user per month.

By Auke Westra, founder of SoftwareWatcher
Sources checked on 19 October 2026

How does SaaS work?

With SaaS, the software runs in a data centre of the supplier or a cloud platform. You log in via the browser or an app. The supplier takes care of servers, security, backups and updates, and all customers work with the same version. The US standards institute NIST describes SaaS as the service in which the customer uses the provider's applications but does not manage the underlying infrastructure.

The opposite of SaaS is software you install yourself on your own servers or computers (on-premise), where you are responsible for management and updates.

Advantages and disadvantages

Advantages: quick to start, access anywhere, no servers of your own, always the latest version and costs that grow with the number of users.
Disadvantages: you pay for as long as you use it, you depend on the internet connection and the supplier, and updates arrive even when they are inconvenient. Customisation is more limited than with your own software.

What should you arrange with SaaS?

If the software processes personal data, the supplier is a processor under the GDPR and you conclude a data processing agreement. Also ask:

where the data is stored and whether the supplier has a certificate such as ISO 27001;
what availability the supplier promises and what happens in an outage;
how you export your data if you cancel, and in what format;
whether there is an API to connect the package to your other software.

Which software helps with this?

Most of the packages on SoftwareWatcher are SaaS. Compare by category and, for each package, check the data processing agreement, where the data is stored and how you get it back when you leave.

See the overview of all software categories.