The guidelines have been developed based on submissions to a public consultation and feedback from initial users of the service, MAS said.
The guidelines give more information on MAS's expectations of the sandbox, including the criteria for entry, MAS said.
The sandbox will now offer greater flexibility to users, relaxing some of the initial criteria and allowing firms to adjust the work they are doing in the course of experiments, MAS said.
MAS will also work closely with applicants during the evaluation and experimentation process, and will publish information on approved applications on its website to increase transparency, it said.
Jacqueline Loh, deputy managing director of MAS, said: "Emerging financial products or services that utilise fintech are becoming more sophisticated. The guidelines reflect MAS’s commitment to building a smart financial centre where innovation is pervasive and technology is used widely. The regulatory sandbox provides a conducive environment where regulatory requirements will be relaxed to enable firms to experiment with promising innovations within boundaries."
The guidelines were announced on the same day as a UK initiative to help startup companies expand into Asia markets.
The Department for International Trade has launched what it calls a one-stop-shop to give advice to fintech businesses looking to scale up internationally, and to match investors with startups in need of investment, it said.
The initiative forms part of a fintech bridge program that the UK has developed with Singapore, Korea and China. These bridges aim to help UK fintech firms and investors access Asian markets, as well as attracting Asian fintech companies and investors to the UK.
Economic secretary Simon Kirby, who launched the initiative at Singapore's inaugural fintech festival, said: "This will be a dedicated service that will support fintech exports and inward investment flows to the UK. It will provide expert advice to those ambitious UK fintechs looking to set up operations in Singapore. And I hope some of you here today will successfully set up operations in this fantastic business environment here in Singapore."