Useful information about taxi services in Amsterdam
Every official taxi must have blue number plates, a price list available from both inside and outside the taxi, and a taxi-driver's pass on the dashboard with photo and name.
At a taxi rank you DO NOT have to take the first taxi waiting - by law you have a free choice to choose the one you prefer.
If you need to run in somewhere, you will need to negotiate a waiting fee with the driver. Around 50 cents per minute is customary.