The move is part of measures being implemented following the murder of Sir David Amess.
Sir David, a Conservative MP, was fatally stabbed during a constituency surgery in Leigh-on-Sea, Essex, in October last year.
The new role, which has a salary of between £29,850 and £37,007, will be a temporary, two-year post as the service is trialled.
A spokesman said the Scottish Parliamentary Corporate Body “is acutely aware of the rising level of online abuse and intimidation towards elected representatives”.
He said: “From April 2023, we will be trialling an in-house service that will identify key words and potentially threatening language relating to MSPs on social media platforms.
“Members will expressly have to opt into the service, which would operate on their behalf.
"Any issues of concern picked up by the service would be escalated to Police Scotland as appropriate.”
An email to MSPs explained: “The software operates by searching for threatening and abusive language across social media platforms.
"The aim is to provide early notice to those members of any potential online threats towards them and to work with partner organisations, including Police Scotland, to offer tailored advice and support.”
It said the move “will complement our existing member security service, which includes the provision of lone worker devices for you and your staff and Police Scotland security surveys of your local offices and homes”.
A job advert says the new role would “assist with setting up a social media monitoring service within the security office, aimed at identifying potential threats to members”.
It adds: “This is a temporary post as we trial this new service. You will be responsible for using the chosen platform to scan for threats.
"You will create daily reports, highlighting any potential concerns and engaging with relevant stakeholders recommending actions to be taken.
"You’ll be the point of contact for service users by offering an effective client management service and play an active role in the members’ staff security engagement network.
"You’ll also build and maintain effective relationships with members, members’ staff, the Parliament’s web and social media team and the Parliament police unit.
"At the end of the trial period, you will support the evaluation of its effectiveness.”
Holyrood’s security office is made up of around 90 staff.