The present report is a comprehensive overview of undulator technologies, which are either already exploited at fully operating free-electron laser facilities or going to be available within the forthcoming 5 years. Main emphasis is given to devices based on permanent magnets and on superconducting technologies, scrutinised in terms of status and perspectives, but also novel concepts with a different readiness level are addressed. A technology comparison based on expected performance and a cost estimate of the undulator system are drawn.

On behalf of the CompactLight Collaboration