The person said the company is expected to announce the plans on Monday. The new capabilities would let third-party developers build services that access content uploaded by Facebook users such as pictures and videos with the users' permission.
Facebook, which has more than 200 million active users worldwide, does not plan to charge for the service.
The company is expected to brief developers on the plan, first reported by the Wall Street Journal on Sunday, at an event it is hosting for developers at its Palo Alto, California headquarters on Monday.
Facebook would not comment on the plans to open its service to outside developers, but the company said it was preparing an announcement on Monday related to developer opportunities.
(Reporting by Alexei Oreskovic; Editing by Diane Craft and Anshuman Daga)