EXR NFT ecosystem technical deep dive — token supply, rarity system, and ERC721Fragementable extension
Our initial research proved that no other system could tie all our NFT collections together the way we wanted — so we architected our own.
Exiled Racers is not your average NFT collection — it’s far from it. The EXR ecosystem comprises 4 distinct NFT collections that all work together — a first ever on Moonbeam:
— Mint Keys [ERC1155]
— Pilots [ERC721)
— Racecraft [ERC721]
— Boosters (Inventory Items) [ERC1155]
All Mint Keys will eventually be burned in exchange for Pilots, Racecrafts, and Boosters, so for now we’ll focus on the Pilot and Racecrafts — we’ll cover the Boosters in a separate post.
We created the ERC721Fragmentable smart contract extension just for Exiled Racers
While the Exiled Racers NFT collections are first and foremost high-quality artworks, we’d be foolish to ignore the bonus racing manager game. We made the decision early on that we wanted to grow the community slowly and steadily, taking care not to flood the market with too many NFTs before the ecosystem, or the game, was ready to handle it. For this reason, we created our own ERC721Fragmentable extension. What does it do? The key is in the name — Fragmentable. The extension allows us to release the collection in “fragments’’. The Pilots and Racecraft contracts both make use of the extension, so when we refer to a “collection”, you can think of it as being applicable to either. Essentially, by using the extension we can release each collection in phases — you can think of them as “mini collections” within the main collection, as they all exist under the same collection in the contract.
For our first drop, ie. the first fragment of the collection, the fragment’s token supply is 3000 (remember this applies to the Pilots and Racecraft collections, so 3000 each). However, the MAX_SUPPLY of each collection is dictated by the contract and is set at 9000.
Put simply, what we’re doing is releasing the first 3000 of the 9000 tokens of each collection. The fragmentable extension allows us to treat each fragment’s metadata separately. So, if we wanted to introduce a new Faction to the story in the second fragment, we could do that without altering any of the first fragment’s (the first 3000 tokens) metadata.
If you’re interested in the technical details of the implementation, you can read the specification in the docs of our smart contracts — https://github.com/Sokoke-Labs/exr-contracts-public/blob/main/docs/erc721fragmentable_spec.md.
The ERC721Fragmentable extension has an impact on rarity, but not in the way you’d expect.
The Pilots and Racecrafts have a 1-to-1 relationship, after all every Racecraft needs a Pilot to fly it… So the explanation that follows applies to both the Pilot and Racecraft collections as they each implement the ERC721Fragmentable design.
The Exiled Racers universe currently has 3 factions — Mercenaries, Augments, and Serfs.
Mercenaries:
Once guns for hire, fighting on behalf of the highest bidder, now formidable components in The Races, known for their grit and aggression in the cockpit.
Augments:
Part human, part machine — casualties of war, or on the verge of death due to starvation and disease, they sold their souls (and bodies) to the Harumi corporation to become biosynthetically-engineered marvels. However, along with a new lease on life comes crippling debt, a burden that may take a lifetime to pay off.
Serfs:
Corporate espionage aimed at disrupting supply lines and critical infrastructure ended with unexpected consequences. A hack designed to override low-level droid and drone communication protocols inadvertently targeted and disabled sentience-safeguards in the Serfs; an autonomous labor force now imbued with consciousness and a newfound thirst for freedom.
Each faction has 5 ranks (with different ranks from each faction sharing a common tier).
EXR NFT rarity distribution is as follows:
That’s a pretty complicated table… what does it mean?
Firstly, the collection is split evenly between the factions, meaning there are an equal number of Mercenaries, Serfs and Augments in the collection. In general, a Mercenary Soldier will roughly have the same rarity (by faction) as a Serf Hauler, because they’re the same Tier, but individual rarity depends on their individual attributes.
The collection distribution by Tier is shown in the Rarity (Distribution %) column. As an example, 43% of the collection belongs to Tier 5. This means that there are an equal number of Soldiers (Mercenary), Haulers (Serf), and HC-AUG-XZ2000s (Augment) that collectively make up 43% of the collection. Technically Tier 5 is the “least rare”, but that’s only statistically speaking. Rarity is also affected by individual attributes, as well as aesthetics (which is for the most part subjective).
Okay, now that we’ve established how the rarity system works according to factions and ranks, how is it affected by the ERC721Fragmentable extension’s design?
Our first release has a supply of 3000 — but remember, this is essentially releasing 3000 out of a potential 9000 that the smart contract (ie the collection) can support. So, if you mint an Exiled Serf that happens to be the #1 ranked in rarity (for the fragment of 3000), will it still be #1 when the supply increases to say 6000? Not necessarily. It is possible that there might be a rarer token (which would be in Tier 1, ie an Exile) that would displace your #1 rank, however you’re still guaranteed to be in the top 2% of the collection (statistically), and given that yours is already highly ranked, it’ll likely still retain one of the top spots — but remember nothing is guaranteed. So, if the first fragment has a supply of 3000, that means there’s 60 Tier 1 Exiled (2% of supply). If fragment 2 also has a supply of 3000, then there are now 120 Tier 1 Exiled out of 6000 (ie. still 2%).
The best way to think of the fragmentable design is that it allows us to release a single collection slowly, in phases. This gives our creative team more time to work on the artwork, and contributes to an overall higher quality project. We could also, in theory, introduce a fourth faction, without diluting the overall supply, as it would use the same Tier system and exist on the same smart contract.
Thanks for listening to our TED talk.
EXR Team.
