Nannybag is a reputable service with hundreds of locations in dozens of cities in Europe. 

Nannybag allows travelers from all over the world to store their luggage in partner shops and hotels (called Nannies) to fully enjoy their day.

The service is available 24/7. The price for is 6€ per luggage for the first 24 hours and then 4€ per additional day. Reservations and payments are made through their website and there is no fee for canceling as long as your reservation time has not started. You only have to book online a luggage storage service in the area of your choice in Amsterdam.

Nannybag has some great features: 
No size/shape or weight limitation of your baggage. Some locations offer free wifi and use of restrooms. Book at the last minute, even 5 minutes before you need to drop your bags off! Locations are reviewed by users to help you decide which location you feel comfortable to use.

Two things to note: 
While it is easy to find their locations on their map, you won’t receive the exact name, address and contact of the shop/hotel until you have booked. 
Be sure to check the times you can drop off and pick up your bags.

Click here to learn more and find a convenient location near you. 
Safety is their priority! Nannybag carefully selects and checks every Nanny. However, it's always best to be prepared for the worst, so Nannybag includes insurance up to 1500€ on each luggage thanks to a partnership with AXA Insurance.