Why NFTs need to be graded? (1/2)

Franck Dupont
OpenGem • GEM score
4 min readJun 15, 2021


There is a problem with NFTs. A big problem.

First, let’s remember why we all love NFTs: we are closer than ever to the persistence and decentralization of an asset.

Why data included in a Non-Fungible Token has a greater value than the data itself? Because of its persistence and its decentralization until the token lives on a decentralized and public blockchain.

As you should know, NFT can attach media like pictures, videos, or even music. So we got so many NFT applications: video game items, digital arts, lottery tickets… But some technical blockchain limitations force NFT platforms to find different ways to store the data depending on its size.

The external storage of assets

Most of the blockchains ask users for “gas fees” to write into it — a kind of contribution to remunerate those who run the chain. The more you want to write into it, the more you have to pay. Today, on Ethereum, a simple transaction costs ~$30, an NFT minting costs around $100…

As the ETH pumped a lot, storing data in an NFT is expensive. Storing 1 Mb costs ~$40k… Guess the price for 1 Gb 😅.

Storing text in the token is ok. This is very light. But storing a picture or a video can be very expensive. So NFT platforms were compelled to find a new way to store media assets. The problem is here: some storage methods make lose the benefit of blockchain persistence & decentralization. So it could decrease the value of an NFT.

What the AFA score takes into account

Each platform that mints NFTs chose its own method to attach an asset to the token. The problem is that these methods don’t offer the same level of decentralization and persistence. That’s why we built the AFA score.

👉 The AFA score evaluates the decentralization and the persistence of NFT assets.

Here are the most used storage methods:

🟢 Stored on the same blockchain as the NFT: you can write what you want in an NFT (ERC-20, for example).
😎 : data gain great decentralization and great persistence.
: the blockchain usually asks for gas to write data. It could be expensive.

🟢 Stored on another blockchain than the NFT: some blockchains have been optimized for heavy assets like video. Blockweave is an example.
😎 : cheaper storage and great data decentralization & persistence.
: the fact that NFT data are stored in different places (2 blockchains) doubles the risk of losing data.

🟡 Stored on IPFS: a distributed system for storing and accessing files or assets.
😎 : the decentralization and the data persistence are greater than storing it on a server.
: it does not guarantee data decentralization & persistence. Somebody needs to “pin” the data to keep it available. Most of the case the platform does it for you. Also, the data can be stored on a unique node.

🟠 Stored via a CDN hosting: a geographically distributed group of servers that works together.
😎 : the data is stored on several computer nodes.
: the owner of the hosting has total control over the data. It can be altered or deleted at any moment.

🔴 Stored on a private server: a traditional private server.
😎 : nothing.
: the owner of the hosting has total control over the data. It can be altered or deleted at any moment. Also, the data is stored on a unique server.

So we classified these methods by data persistence level & data decentralization level:

The AFA score is based on these two scales.

We need to take into account something else

On traditional blockchains like Ethereum or Binance Smart Chain, some NFT platforms let artists upload their own creations (e.g. Rarible). To keep its value, the asset must not be reduced or altered. So the platform doesn’t have control over the asset size. The money needed to store a large-sized asset on those blockchains can reach millions of dollars 😰.

👉 We are aware of this difficulty. So we consider that the best storing method for uploaded content is a cheaper media-storing oriented blockchain like Blockweave.

“phew…! Guys, we still can reach a high AFA score!”

We’re not here to judge

We built a scoring scheme to let non-technical users know exactly where are the data they own from their NFT and how it can be altered and persistent.

As the technology keeps moving on, we need to be up-to-date about all the new storage methods that try to ensure great decentralization & data persistence. We are excited to see teams like Arweave trying to reach this step, and we need you, the NFT community, to let us know when something new is showing up 👋.

We are deeply in love with the NFT ecosystem and the blockchain. We love how the dapps are growing. We want the NFTs democratization, and we believe the AFA score can really help reach this step.

Now that you have all this in mind, get ready to deep dive into the AFA scoring scheme.

🧐 Next article: “How the AFA score is calculated? 2/2”