The latest investment follows an initial seed funding round of £2.5m in 2017 and current partnership with fintech firm GoCompare Group, as the robo-adviser moves to "revolutionise" the UK mortgage market.
The funding will be used to develop the robo-adviser and invest further in artificial intelligence, after launching earlier this year.
Regulated by the Financial Conduct Authority, MortgageGym offers consumers a free 60-second "mortgage-matcher" - a platform it supports via integration with Experian credit files and lenders' live scorecards.
John Ingram, co-founder of MortgageGym, said the company has seen strong demands from its customer base for human advice to remain part of the mortgage process and therefore all customers receive independent intermediary advice following the matching service.
Mr Ingram said: "The process means that all of the slow work that would be time consuming for both broker and customer to get to the point of advice has been done by a computer.
"We do not expect to see human intermediary advice disappear from the mortgage process - our plan is to very much embrace consumer demand for the human experience but to enhance it with technology."
Mr Ingram said he believes MortgageGym’s platform answers the FCA's call in its mortgage market study to further support mortgage applicants in identifying and comparing products available to them.
He said: "It offers people greater visibility of the mortgage market and what is available to them - technology enables both the adviser and consumer to make better decisions."
At the Financial Services Expo in London last week, HSBC’s head of intermediary mortgages said the mortgage industry needed to embrace technology as a "friend not foe" to create a hybrid model in which digital capability helps brokers offer the best possible advice.
Mr Ingram said: "We have carefully chosen investors that not only bring funds, but invaluable, symbiotic business models and expertise - as a result, we do not need to invest in costly customer acquisition or building a broker-base.
"This places us in a much stronger position than our peers as it allows us to invest the new capital in improving our technology – thereby improving customers’ choices."
He added: "The UK mortgage market is poised for digital revolution, and we are here to drive it."
Sebastian Riemann, mortgage consultant at Libra Financial Planning, said robo-advisers seemed to be going down the hybrid proposition route rather than actual robo-advice with little human input.
He said: "This is not anything new - any broker in essence uses some form of technology to streamline the mortgage process, it is just the extent to which you do that."