from Hacker News

Here is the ndef record so you can do this yourself for free (we have an orderable product but it's not actually needed and we sell it at-cost):

ndef: { lock: false, // keeping it unlocked allows users to modify it to remove the android app link if needed // structure documentation: https://gitlab.com/gototags/public/-/tree/main/Desktop%20App... records: [ {type: 'WEBSITE', url: 'https://guavahealth.com/nfc/YOUR_ID'}, // create a random unique string ID per tag {type: 'AAR', packageName: 'com.guavahealth.app'} ] }

Fancy demo video: https://www.youtube.com/watch?v=018IItVGXvA

This started as my colleague Awadi hacking an NFC tag and sticking it to his water bottle and repeatedly showing us his cool blue checkmark animation. Then a couple more of us got involved and did a 5-day hackathon to make it work for all health log types in Guava, and got some stickers printed!

There's a lot of variety in the choice of NFC tag material, antenna, chip, etc., and we chose the more expensive sticker tags so they'd be waterproof and work on metal. For certain use cases you could use tags that are much cheaper and look different though. One thing you can do is create a huge board on your wall with all the 20-100 (???) things you log for biohacking or whatever, and use a unique NFC tag to log each one. We wrote the software to allow configuring custom types, so it's fairly unlimited.