HCL Domino is the server behind HCL Notes. It stores mail and applications, controls access and replicates data between servers and users.
HCL Domino is the server behind HCL Notes. It stores mail and applications, controls who may see what, and replicates data between servers and users. Without Domino, the Notes client is just an empty program.
What does a Domino server do?
Domino is at once a mail server, application server, web server and directory server. It is unusual for one server to cover so many roles, and it is one reason the platform became so widespread in companies and public institutions.
- Mail: Domino receives, sends and stores mail. Mailboxes are NSF files on the server.
- Applications: All Notes applications live as databases on the server and can run agents and scheduled jobs.
- Web: Domino has a built in HTTP server, so applications can be shown in the browser through XPages or Domino REST API.
- Directory: Domino Directory holds users, groups and server settings.
- Replication: Domino keeps copies of databases synchronised across servers and clients.
Which operating systems does Domino run on?
Domino is available for Windows Server and Linux. Most new installations run on Linux, often in Docker containers. That means lower licence costs and easier updates. Many companies still run on older Windows servers, and moving to Linux is a typical task for a Domino administrator.
Versions and support
HCL releases new versions regularly. Domino 12 arrived in 2021, Domino 14 in 2023 and Domino 14.5 in 2025. Older versions such as 9 and 10 are out of support. If you still run them, it is both a security risk and a problem for a later migration. We always recommend upgrading before moving data off the platform.
Common questions about HCL Domino
What is the difference between Notes and Domino?
Notes is the client on the user's PC. Domino is the server. You can have Domino without the Notes client, for example if users only use web and mobile, but not the other way round.
How many servers do you need?
A small company can manage with one server. Larger organisations typically have separate servers for mail, applications and web, often in two data centres to stay up during an outage.
Can Domino run in the cloud?
Yes. Domino can run at Hetzner, Azure, AWS or a local hosting provider. We offer Domino hosting and monitoring around the clock.
Help with Domino operations
We monitor Domino servers for companies and take operational responsibility, so the IT department can spend its time elsewhere. Read about server monitoring and Notes support.