Once advice has been given to the customer Brilliant Solutions will receive the application electronically.
Brilliant will send out the initial regulatory documents and processes the application before passing it back to an FBS underwriter to approve the offer.
Mark Bogard, chief executive of Family Building Society, said: “Brilliant was the perfect match for our needs. As mortgage experts the company not only has the knowledge but also the most impressive mortgage processing software system in the marketplace.
“Leveraging these key skills allows us to expand our underwriting team internally and use more staff to build the society.
Brilliant’s software allows FBS to track the application through each stage of the process.
Matthew Arena, managing director of Brilliant Solutions, said: “It is a fantastic project to be involved in. The team at FBS has brought real innovation to the market and between us we have developed one of the most efficient and knowledgeable mortgage operations in the market.”
The two companies are already discussing other ways of working together to enhance the building society’s offering further.
FBS, set up by the National Counties Building Society, launched this month with a range of mortgage products intended to allow families to financially support each other.
The building society plans to extend the mortgage outsourcing service to intermediary applications.