Selling and trading

Want to trade your NL crypto stamp? You can! You can transfer the digital stamp to other users or sell it directly.

How can I sell the digital twin via the blockchain?

You can transfer your NL crypto stamp to other users via the blockchain. For this you need the 'secret word list'. This becomes visible if you carefully remove the protective film on the back of the stamp at code [2]. Then scan the QR code or enter your secret word list at Keep this list in a safe place and do not share it with anyone.

How do onchain sales work?

You can also buy the digital twin of your NL crypto stamp directly via the blockchain like this:

  1. Go to the onchain store at the Austrian website at using a browser with a cryptocurrency wallet. Opera and Brave have this built in by default. Then connect to the appropriate network via If you are you using Chrome or Firefox, download the MetaMask extension to add a cryptocurrency wallet.
  2. Add the cryptocurrency Polygon (MATIC) to your wallet. You can buy this with a credit card at
  3. Use the Polygon in your wallet to buy the NL crypto stamp in the onchain store. Payment successful? The digital twin is now in your wallet!
  4. If you would also like to request the corresponding physical stamp, you can do this from 21 October 2022 via the onchain store. You have up to 5 years after your purchase to request your physical stamp.

What if my transaction in the blockchain has failed?

If you want to perform a transaction in the blockchain, you have to pay gas fees. These are the transaction fees that users pay to miners on a blockchain protocol to have their transaction included in a block. Only when a transaction is included in a block does it actually take place.?The amount you pay depends on exactly what you want to do and how busy it is at the time. You must pay the amount to the miners. You can adjust these gas fees to a lower amount yourself, but you do then run the risk of the transaction failing. Then you lose the cryptocurrency you paid to the miners. Please note: PostNL has no influence on this and receives benefit from this. And we cannot help you get back lost gas fees.