What is ERC 404: Semi Fungible Tokens Explained

Written by
Shivam Srivastava
May 17, 2024
min. read

What is ERC-404 aka Semi-Fungible Tokens?

One the latest innovation to stir debate among blockchain developers is ERC-404, dubbed as Semi-Fungible Tokens (SFTs).

This new, yet unofficial token standard has emerged from the depths of the crypto community's collective ingenuity, promising to blend the best aspects of fungible tokens (like ERC-20) and non-fungible tokens (NFTs, such as those following the ERC-721 standard).

This article delves into the origin, mechanism, implications, and the cautious optimism surrounding ERC-404 and its first implementation project, Pandora.

ERC-404: The Origin Story

The narrative of ERC-404 is as captivating as it is instructive, unfolding in three distinct parts that highlight both the potential and pitfalls of rapid innovation in the blockchain space.

Part 1: The Diamond in the Rough

The genesis of ERC-404 can be traced back to a crypto project named Emerald. Launched amidst considerable hype, Emerald proposed an intriguing way to merge the functionalities of ERC-20 and ERC-721 tokens. This concept, while not fully understood, intrigued investors and enthusiasts alike, offering a glimpse into new market dynamics for NFTs. However, the project faced a significant setback when it was purportedly "hacked," leading to substantial financial losses for investors. The circumstances around this event remain murky, with speculations of a possible insider scam.

Part 2: The Truth is Revealed

In the aftermath, a group of crypto aficionados reached out to the Emerald developer, aiming to salvage and relaunch the project. This collaboration revealed a shocking truth: the developer had relied on ChatGPT for the project's development, casting doubts on their technical expertise and intentions.

Part 3: A New Beginning

Undeterred by this revelation, the group decided to abandon the dubious developer and instead forge a new path. This collective effort led to the creation of ERC-404 and its first use case, Pandora, marking a fresh start for the initial concept behind Emerald.

Understanding ERC-404 and Pandora

At its core, ERC-404 represents an innovative, albeit unofficial, token standard that amalgamates the characteristics of fungible and non-fungible tokens.

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The Mechanics of ERC-404 and Pandora

Pandora exemplifies the ERC-404 standard by offering a hybrid model where the purchase of a Pandora token grants the buyer not only a fungible asset but also a unique NFT with randomized traits. This model addresses one of the longstanding challenges in the NFT space: liquidity.

Traditionally, NFT owners had to navigate the cumbersome process of listing and selling their tokens on marketplaces, often facing uncertain demand. ERC-404 tokens, however, can be sold directly, with the associated NFT being burned upon sale, thereby providing a more fluid and dynamic market mechanism.

The Significance of ERC-404

The introduction of ERC-404 and projects like Pandora brings several implications for the crypto and NFT ecosystems:

  • Enhanced Liquidity: By enabling the fractionalization and easier transferability of NFTs, ERC-404 could significantly improve market liquidity.
  • Innovation in Token Standards: ERC-404 represents a step towards more complex and versatile token standards that can cater to a broader range of applications and use cases.
  • Experimental Nature: Being an unofficial and unaudited standard, ERC-404 invites both curiosity and caution. Its experimental status means that while it opens new avenues for creativity, it also poses risks, especially from potential scams.

Community Reactions and Considerations

The crypto community's response to ERC-404 has been a mix of excitement and skepticism. On one hand, the novelty and potential of combining fungible and non-fungible elements in a single token standard have garnered interest. On the other hand, the cautionary tale of its origins and the experimental nature of ERC-404 remind investors and developers of the need for diligence and the risks of untested innovations.

Cautionary Advice

As with any nascent technology or concept in the crypto space, due diligence is paramount. The allure of innovation should not overshadow the need for security, transparency, and accountability. Potential investors and participants in ERC-404 projects are advised to proceed with caution, mindful of the standard's experimental status and the inherent risks of emerging crypto technologies.


ERC-404, or Semi-Fungible Tokens, represent a fascinating development in the blockchain and crypto arena, offering a novel approach to blending the characteristics of fungible and non-fungible tokens. While the concept holds promise for enhancing liquidity and innovation in token standards, it also underscores the challenges and risks associated with rapid technological advancements. As the crypto community navigates this new terrain, the story of ERC-404 serves as a reminder of the importance of collaboration, transparency, and caution in the pursuit of blockchain innovation.