What is ERC404 and who exactly created it?

Everything you need to know about today's top meta in web3.

What do you get when you smash together an ERC20 fungible token contract and an ERC721/1155 non-fungible token contract?

ERC404. No, this is not an error, it is a new quasi-token standard that is drawing serious attention in the crypto world.

The Buzz: From Emerald to Pandora

This story effectively begins around the end of January 2024 when a project called Emerald was launched. It immediately began generating massive hype for its novel use of both fungible and non-fungible contracts, in a way that opened the door to entirely new market mechanics. No one, probably not even the dev knew how revolutionary it would become, but the market was intrigued and buyers were a plenty.

However, before it truly blasted off the contract was hacked, pulling the plug on the project’s rocket fuel before it made it into orbit. It’s worth noting that there is speculation that the dev was behind the hack. Hitting the self-destruct button as it were, costing investors thousands of dollars.

This is not where the story ends, because two enterprising devs reached out to the Emerald creator offering to help him resurrect the project. After what was apparently a quick consultation the fix was identified, but so too was something far more troubling. The Emerald dev was no dev at all. He was a guy with a little bit of know-how, and a whole lot of help from ChatGPT.

With this revelation, the real devs, who came to the rescue decided to go their own way and develop a new project using the newfound ERC404 standard. Their creation, Pandora. This project, helmed by a small but capable team did what Emerald couldn’t. Launch a project that wouldn’t just make it to orbit. They built a rocket ship that blasted a hole in the moon.

What makes Pandora so unique is the ingenious mechanic that allowed the fungible token to simultaneously exist as an NFT. Put simply, owning 1 Pandora token also gets you a “replicant” NFT associated with said token. This NFT is automatically minted to your wallet, complete with randomized traits you expect from an NFT collection. If you like your NFT, you can keep it or sell via an NFT marketplace. If you’re digging your new NFT, you can sell your Pandora token on a high-liquidity DEX such as Uniswap. Upon its sale, the NFT associated with it gets burned and a new NFT is minted for the subsequent owner.

Still with me? Good. Because this is some paradigm shifting ish.

What exactly are ERC404 tokens?

ERC404 is an experimental token standard has not gone through the usual Ethereum Improvement Proposal (“EIP”) process. It combines the characteristics of fungible tokens and NFTs.

Projects building on ERC404 offer ERC20 fungible tokens, programmatically connected NFTs. As seen with Pandora, 1 full ERC20 token will result in the minting of an NFT in their wallet. However, if a user has less than 1 full ERC20 token, no NFT will be generated.

Be warned, however, ERC404 has not been audited, so there may be vulnerabilities and exploits that have yet to be uncovered. Users should know and accept these risks before investing in any 404 projects.

Advantages of ERC404

Better Liquidity

ERC404 benefits from the higher liquidity of ERC20 tokens, effectively allowing NFTs to be traded through a liquidity pool of fungible tokens on any decentralized exchange. In the olden days, NFTs listed on marketplaces lay in wait for a buyer. Due to the illiquid nature of NFT markets, a sale can take a very long time.


Highly sought-after NFTs may be fractionalized through various protocols. But they still suffer from the liquidity issue. In these protocols, an NFT is locked in a contract and shares are issued against it. Now, ERC404 achieves native fractionalization of NFT collections where traders can buy fractions of an NFT in the form of an ERC20 token.


This novel dynamic will almost certainly open the door for a whole new frontier of interactive and gamified experiences. With ERC404 being fresh out of the blocks, only a few projects have emerged that have begun exploring the limits of what this standard can evolve into.

Who really created ERC404?

Many people believe that ERC404 was created by the Emerald “dev” and his ChatGPT copilot. Some people think that Pandora was the creator. The truth is, this groundbreaking contract was developed years ago by EthereansOS. It lay in wait for Emerald to bring it to the web3 world’s attention.

EthereansOS (Ethereans Labs AG) is an “Operating System” for Ethereum that empowers builders to create projects with no code and little technical ability. They launched the first ERC 404 token $OS on October 28th 2021, but have since grown their offerings substantially since then, including a Launch Factory to build and deploy your own 404 tokens.'

It’s worth noting that, according to this tweet there may have been tokens that launched even earlier in 2020 with these dual token features, but we couldn’t find much on these projects at the time of this writing. To us, it appears that EthereansOS was the first to solidify and subsequently improve the standard.

If you have any details on these projects please comment below or reach out to us so we can set the record straight.

Other ERC404 projects to watch

It didn’t take long for other devs in the space to see the potential in ERC404, and to begin creating their own projects. Here is a look at a few that have jumped head first into this new meta, and what makes their projects stand out.

In the style of DeGods, DeFrogs is a collection of 10,000 enabled by erc404. They claim they are the 1st ERC404 PFP. Whether or not that’s true, they are putting up a solid fight to be one of the top tokens in the category.

Non-Playable Coin (NPC) is a fusion of a memecoin and an NFT or as they call it, a meme-fungible token (MFT). Amusingly, the fixed supply of 8,050,126,520 NPC tokens was designed to ensure fair distribution and accessibility to all 8+ billion people on Earth. It’s operational on Ethereum, and tradable via Uniswap as well as on Coinbase’s highly gas efficient L2, Base.

Each NPC token can be redeemed for a custom non-playable character, presenting countless unique combinations for every individual on the planet. Furthermore, users are empowered to generate their own NPC-related images using AI, fostering creativity and engagement.

A collection of 10,000 pixel penguins, resurrected from the abandoned “Flippies” collection, originally on the Solana network, The founding team disappeared four months after its mint in 2022, but loyal holders retained these cute birds in their wallets through the bull and bear NFT markets.

For an update list projects, we refer you to the ERC404 category page on CoinGecko.

Our take

Spotting trends before they become popular is a hallmark of successful investors and enthusiasts in the crypto space. Recognizing the potential of ERC404 tokens early on can be a game-changer, providing an opportunity to ride the wave of their increasing popularity and potential for growth. The unique combination of token and NFT features within ERC404 tokens has set them apart from traditional cryptocurrencies, paving the way for exciting new possibilities in the market.

Whether or not this new standard will become a staple of the crypto world, or if it is just another short live narrative remains to be seen. Either way there are bound to be projects that put the standard to good use, becoming top performers in the coming years.

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