On-premises / On-premise
Different formsUse on-premises for the location or deployment model. Premises means a building or property; premise means an idea, assumption or proposition. The shortened technical form on-prem is common and useful where the audience understands it.
On-premises
Use when
You mean software or infrastructure hosted, or equipment located, at an organisation's own physical site rather than in an external cloud or hosted environment.
Example
“The application is hosted on-premises in the agency's data centre.”
On-premise
Use when
Avoid this form in formal writing when referring to infrastructure located on an organisation's premises.
Example
“Replace 'on-premise server' with 'on-premises server'.”
Quick check
on-premise server, on-premise deployment, on-premise infrastructure, off-premise environment
Usage note
On-premise is widespread in technology writing and will usually be understood, but Microsoft's technical style guide recommends on-premises for the location sense.