For this part it is irrelevant which of our products you bought or how tech savy you are! We will lead you through this here or in our group linked in the menue.

Some like to read, some like to watch tutorials which is why you will find a variety of documentation available here on how to write different sorts of payment-links to your Plebtag. So lets first decide what to do :

Create or update a Boltcard – for bigger amounts

Write a paylink to generate simple Voucher- or Tippingcards

Batch-generate a bunch of cards for your event, contest or donation project

Create a Boltcard

The easiest way to create and run a Boltcard is with the BoltCard Wallet App. Be aware that this is a custodial solution. Heres the link from the apple store and here for Android. You can rund a BoltCard Hub yourself to make this a sovereign solution, see Links.

To write the BoltCard feature with LNbits you will need some things :

First of all an LNbits instance in clearnet* opened with chrome. First thing you want to do is install the boltcard extension for your wallet.

*If your node is a tor-only node it will otherwise generate links that can only be read with the tor-option set by merchants POS systems or other users´ wallets. Please consider running your own LNbits instance. You could as well use the official demo server of LNbits or one of your friends´ but these should not be used for high-availability or longterm production use cases nor for bigger amounts. Which ever you use, this is where we will produce the wallet and define the card and its keys to write to the tags.

If you installed LNbits, we can start with downloading the Boltcard app from the Play-Store or from github to write your keys to the tiny little tags within your card.

Note that because of limitations of iOS you will need either just an android phone. Instead of doing it on a mobile you can as well write to them from your dektop pc with google chrome + the boltcard app as well as a physical nfc-writer for NTAG424 cards(only!).

This method sets up the secure version of an NFC Tag that communicates to your lnbits boltcard webservice to authenticate each single request before allowing a payment. You will find a textual description of the process here and in the following video

🚨🚨🚨 The keys you generate are needed when you want to rewrite your card in the future,

DO NOT DELETE THOSE KEYS without a backup 🚨🚨🚨

A .json file will be force-downloaded in the end of the writing process with which you could recover those wallets but do not play with 🔥 deleting the keys, card or even the wallet because you have that file. IIf you delete the wallet or the card or if you regenerate new keys your old setup will be gone from the database and without backup cannot help you to rewrite your card ever again.

If you want to gift a card not with a plain voucherlink (recommended because of easier rewrite) but with a Boltcard, please include the following data for the user to be able to make full use of your present.

Change a Boltcard

Got a card from Coincorner or have written to your plebtag once and now want to write another wallet on it ? This is a bit tricky.

First you need to start deleting the old values ->where they were written<-. Means, if you have a CoinCorner Boltcard you will have to start the wiping process from there. If you have written a wallet to your tag with LNbits boltcard extension you will also need the old keys of this card to be able to do so – just that you yourself are responsible for storing them, so we hope you did 🙂 If you have deleted the card in the boltcard extension without making a key-backup the card is bricked.

If putting in the old keys fails x times you will have to succeed the same amount of taps with the right ones before it will be unlocked again. You can find more info on that in this document from NXP chapter 7.4.

To make all this easier LNbits offers a QR-Code to do so. Start the video fromon 2:40. Experts can do this manually according to this written tutorial.

You will need the BoltCard App / NXP-Write Tool to delete the old values as well as an android phone. Open LNbits through Chrome to not run into further issues.

If you don´t have the old keys there is no way of writing to those tags again.

Remember that this is a security feature of NTAG424 cards and has nothing to do with the boltcard-service or -app.

Simple printed tipping cards, voucher or contest

This use case does not require high security because the link might not be used for long like e.g. as long as your event goes or as a present that will be redeemed soon. The missing security features also lets you use Tags fromon NTAG21*.

Within this process we will write a simple LNURLw to the tag without any further security features. But for events it is the most common give-away voucher and can also be used for event games where some out of all cards have a winning-option. If you are into tinkering you can e.g. turn something on (lights, music, a confetti machine,..) when a certain card is used.

if you do speak german or spanish we recommend the following videos but since the process is not very complicated you might be able to make sense out of them whatever language you speak. Check out the links in the shownotes, too. You can also find a textual description on how to write those here.

Writing a lot of simple voucher tags at once

For a static paylink you can use this NFC-BRRR machine we made for Bitcoin Amsterdam. With this tool you can set up from 2-999 funded wallets and write them through a browser to each card in a very short timeframe. Note that this as well only works on android + chrome.

NFCCards with NTAG 216 can carry just 1 written link – usually this would be the one to pay with. But that´s not enough, right? To be able to refill the card or see the balance NFC-BRRR can generate stickers carrying an Import-Key for e.g. BlueWallet for those wallets. Put the right(!) sticker on each card or flyer and your guests are set to use some juice- or beertaps!

What this tool will do for you

NFC-Brrr does not only create voucher that can be used to redeem funds from 1 wallet by x vouchers but it creates a dedicated wallet for each set of voucher or set of links you generate. That enables your users to use those card not only via the given card but also via LNbits webintereface and by importing it to BlueWallet. We recommend this setup especially for NFC-Cards that you write for others. In detail you can

  • Create wallets and all links needed for each card
  • Fund the cards with your LNbits wallet
  • Write the chosen link onto a bunch of cards
  • Fill a sticker-template with the chosen link to import or top-up the wallet (Avery 25×25-S)

We recommend to write the LNURLw to the card, the LNDhub to a flyer and the LNURLp to a sticker you put on the cards. A common number will be created for all those links so that you know which belongs to the other when confectioning your NFC giveways 🙂 Please see the help section of the tool for further FAQs before you start.

Now let´s get your wallets ready and BRRRR some cards !

If you are interested in the github you can find it here.

Explanation on the tool


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