In a short statement, the supplier confirmed Buckley will "remain available to the board for a period of time" and expects to make a further announcement in due course.
Gary Shaw, Nektan Founder and Executive Director, has taken up the role of Interim CEO.
Buckley said: "As part of the recent restructuring of the business, now is the right moment for me to step away from the role of CEO.
"The business has a solid foundation of proprietary technology and a fast-growing B2B business that will help it capitalise on the many global opportunities ahead."
Buckley previously stated her hope Q4 would produce improved financial results for Nektan; the improvements did not come as the supplier saw overall Q4 revenue fall 29% year-on-year, to £4.1m ($5m).
During that trading update, Buckley said: "A number of steps to enhance our product offering, including the launch of bingo and improved player journeys, have been completed in Q4 and we look forward to the new financial year with optimism."
Buckley’s resignation comes less than two weeks after Nektan posted the update.
