Crypto Composables — Building Blocks and Applications

Matt Lockyer
Published in
5 min readMay 1, 2018


Image: Canva

The first post introducing the ERC-998 Composable Non-Fungible Token Standard for Ethereum gained a lot of traction. Lots of members of the community reached out with some awesome comments including: @atphyses, Mikhail Larionov, Maciej Górski. After a number of phone calls and emails regarding the post, everybody wanted to know… What’s the project?

There is no project… and no token sale.

My passion lies in expanding the standard components of Ethereum so developers can use them to create amazing, inter-operable experiences. This will spur adoption of crypto and blockchain technologies. A great example of this mental model is Trent McConaghy’s recent tweet on analog computing circuits. Staring into your computer screen right now, think how it all came to be from tiny components and transistors.

Okay. You’re making a standard for composing fungible ERC-20 tokens (FTs) and non-fungible ERC-721 tokens (NFTs) into complex sets and hierarchies. So what? There are many use cases, some practical and some fun (perhaps equally profitable). A JavaScript hero of mine, Eric Elliott, has spent many years beating a concept into our heads from the Gang of Four

Favor object composition over class inheritance

I’m going to walk through a few use cases introducing the concept of object composition on the blockchain. These examples will be using the pre-existing standard Ethereum tokens and a new extension of NFTs called Composables.

Use Case — Legal

Legal contracts are a mess. They’re long, incomprehensible and bespoke. Knowledge arbitrage has served the legal system for centuries. Now the nerds are banging at the door trying to automate agreements and legal processes for the people. How does this relate to composables?

Most legal contracts are nothing more than a set of clauses binding two or more parties into an agreement. Legal contracts could easily be composed from a set of standard clauses with inputs for parties. The clauses would be non-fungible tokens, unique and able to be custom fitted to the overall goals of the contract. The contract itself would be an ERC-998 composable defining metadata about parties involved. The composable and the clauses owned by it can now form a complex legal agreement.

Use Case — Supply Chain Provenance

Lots of projects in blockchain are exploring supply chain management and provenance. An immutable shared record is a logical fit for this industry. An implementation that is narrow in scope or bulky will have a hard time gaining traction with application developers and businesses seeking to adopt a standard. It may not be obvious how composables fit in here, but take a look.

A coffee farmer harvests a field into 500, 25kg bags of beans. They go off on different trucks to different roasters. At the roasters, bags receive data about the roast type. They end up on different trucks, on their way to shops. Once at the shop the beans are used, producing delicious coffee. A Brooklyn hipster scans a QR code and sees the beans she is drinking, where they were roasted, the roast type, the field, the farmer… You get the point. A tremendous amount of perceived value.

We can track several fields of coffee, from harvest to cup. By minting a new ERC-998 Composable for each harvest, we can then attach ERC-721 Non-Fungible Tokens to represent the bags, and if the bags also support the composable interface, we can place fungible ERC-20 tokens inside. This way, a cup of coffee can be seen as spending an amount of “bean” tokens from a specific bag, roast, roaster, harvest, farmer. Phew.

Use Case — Virtual Assets

If you’ve been in crypto for a minute, you’ve heard about CryptoKitties. Bringing the ERC-721 standard forward was a solid move by Dieter Shirley and parent company Axiom Zen. It forced the community to come together around a standard interface for NFTs. This meant companies like could easily bring on new digital assets and could build a layer 2 social network for users who owned digital NFT avatars like CryptoKitties.

Imagine an in-game item like a shield, with 5 mounts for special gemstones. You find a few stones, mount them, and decide to sell the shield. You can take this composition to a decentralized market. Thanks to the composable interface all the assets can be enumerated for the sale. Only a single purchase is needed to trade the shield to it’s new owner. Once received, the new owner can transfer the stones from the shield, perhaps equipping them to special armor where the combination is more powerful than it was with the shield. Lots to ponder.


Composable crypto assets are the next evolution of non-fungibles for the Ethereum blockchain and community’s decentralized applications. There are practical use cases that solve real world problems and fun use cases that give virtual game assets a whole new level of depth both in-game and in markets. Standard interfaces make it easier than ever to mix and match assets across protocols and decentralized applications. This is leading to more cross over, experimentation and communication in the community. Join the discussion here and help move this standard forward.



Matt Lockyer

Building Blockchain Solutions to Real World Problems - "The revolution will not be centralized."