Singapore has joined number of countries by ending passport stamping at exit effective today (April 22, 2019).
You still need to fill out an immigration form when entering the country and passport is stamped at that time.
Here’s an excerpt from the Jakarta Post (access their piece here):
Foreigners leaving Singapore will no longer need to have their passports stamped from next Monday.
The Immigration and Checkpoints Authority (ICA) said yesterday that it would, from April 22, “cease the issuance of departure immigration endorsements”, meaning stamps of departure dates on travel documents.
The move is part of ongoing efforts to streamline checkpoint procedures and make it more efficient to clear departure immigration, ICA added.
Since September 2016, foreign travelers whose fingerprints were enrolled via the BioScreen system on arrival in Singapore have been able to use automated lanes when they leave the country. Such travelers do not receive stamps in their passports.
Singapore immigration had a small display out at the exit today noting that passports are no longer stamped.
You could always ask why there is a need for that immigration form to be filled out when entering the country that would save more time, money and lessen lines that previously were non-existent (they are all scanned)?
Sometimes the stamp is good to have to prove that you have exited. For some reason, my exit from Australia was not once recorded last year (CX BNE-HKG flight) and I had issues checking for my DPS-SYD flight couple of months later. The agent had to call specific number and my exit information was updated, after which they were able to issue the boarding pass.