docs/token-standards.md

Pezkuwi Token Standards (PEZ-20 & PEZ-721)

Pezkuwi defines a small, familiar family of token standards so that anyone coming from Ethereum (ERC-20 / ERC-721), BNB Chain (BEP-20), or Tron (TRC-20) immediately understands how tokens work on Pezkuwi:

Standard	What it is	Backed by
PEZ-20	Fungible tokens (currencies, stablecoins, LP tokens)	pallet-assets on Asset Hub
PEZ-721	Non-fungible tokens (NFTs, collectibles, certificates)	pallet-nfts on Asset Hub

Important — these are not smart-contract standards. Pezkuwi Asset Hub has no EVM and no smart-contract layer. PEZ-20 and PEZ-721 are runtime-native standards: a token is not a deployed contract with an address — it is a registered asset with an on-chain ID managed directly by the runtime. This makes tokens cheaper, faster, and impossible to brick with buggy contract code. The interface below is the conceptual equivalent of ERC-20/721, mapped to native runtime calls.

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PEZ-20 — Fungible Token Standard

A PEZ-20 token is a fungible asset registered in the Assets pallet on Pezkuwi Asset Hub. Each token is identified by a numeric Asset ID (the equivalent of an ERC-20 contract address).

Identity

Concept	Ethereum (ERC-20)	Pezkuwi (PEZ-20)
Token identity	Contract address 0x…	Asset ID (u32)
Where it lives	A deployed contract	The Assets pallet registry
Native coin	ETH is not an ERC-20	The native gas token (Balances) is not a PEZ-20

Just as ETH itself is not an ERC-20 token, the Pezkuwi native/gas token is not a PEZ-20 token — it lives in the Balances pallet. PEZ-20 covers all issued fungible assets.

Required metadata

Every compliant PEZ-20 token MUST set asset metadata via assets.set_metadata:

Field	Type	ERC-20 equivalent
name	bytes	name()
symbol	bytes	symbol()
decimals	u8	decimals()

Interface

ERC-20 method	PEZ-20 (extrinsic / storage)	Notes
totalSupply()	Assets.Asset(id).supply	read
balanceOf(owner)	Assets.Account(id, owner).balance	read
transfer(to, amount)	assets.transfer(id, to, amount)	also transfer_keep_alive
approve(spender, amount)	assets.approve_transfer(id, spender, amount)	allowance
allowance(owner, spender)	Assets.Approvals(id, owner, spender)	read
transferFrom(from, to, amount)	assets.transfer_approved(id, from, to, amount)	spend allowance
mint (if mintable)	assets.mint(id, to, amount)	issuer/admin only
burn	assets.burn(id, who, amount)	admin, or assets.transfer to a burn flow

Roles

PEZ-20 inherits the pallet-assets role model, which is richer than ERC-20:

• Owner — can reassign the other roles and set metadata.
• Issuer — may mint.
• Admin — may burn, freeze, and force transfers.
• Freezer — may freeze individual accounts or the whole asset.

A token MAY renounce roles (e.g. set issuer to a burn address) to make supply fixed — the equivalent of an ERC-20 with mint removed.

Events

Assets.Transferred, Assets.Issued, Assets.Burned, Assets.ApprovedTransfer, Assets.MetadataSet — the audit trail equivalent of ERC-20 Transfer / Approval events.

Variants

Variant	Pallet	Use case
PEZ-20	Assets	Locally-issued fungibles (default)
PEZ-20-F (foreign)	ForeignAssets	Bridged / XCM assets, keyed by origin location instead of a u32 ID
PEZ-20-LP (pool)	PoolAssets	Automatically-minted liquidity-provider tokens from on-chain pools

All three share the PEZ-20 interface; they differ only in how the asset is keyed and who can issue it.

Compliance checklist

A token is PEZ-20 compliant if it:

1. is registered in Assets (or ForeignAssets / PoolAssets),
2. has name, symbol, and decimals metadata set,
3. exposes transfers and the approve / transfer-approved allowance flow,
4. publishes its role policy (mintable vs fixed supply).

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PEZ-721 — Non-Fungible Token Standard

A PEZ-721 token is a non-fungible item in the Nfts pallet on Pezkuwi Asset Hub. NFTs are grouped into collections; each item is unique within its collection.

Identity

Concept	Ethereum (ERC-721)	Pezkuwi (PEZ-721)
Collection	Contract address	Collection ID (u32)
Token	tokenId (uint256)	Item ID (u32) within a collection
Full identity	(contract, tokenId)	(collectionId, itemId)

Interface

ERC-721 method	PEZ-721 (extrinsic / storage)
ownerOf(tokenId)	Nfts.Item(collection, item).owner
balanceOf(owner)	Nfts.Account(owner, collection, item) (iterated)
mint(to, tokenId)	nfts.mint(collection, item, to, …)
transferFrom(from, to, tokenId)	nfts.transfer(collection, item, to)
approve(spender, tokenId)	nfts.approve_transfer(collection, item, spender, …)
tokenURI(tokenId)	nfts.set_metadata(collection, item, data) → item metadata
collection metadata	nfts.set_collection_metadata(collection, data)

Capabilities beyond ERC-721

pallet-nfts gives PEZ-721 features ERC-721 needs extra contracts for:

• Royalties / attributes — native per-item and per-collection attributes.
• Trading — on-chain set_price / buy_item without a marketplace contract.
• Locks & soulbound — items or metadata can be made non-transferable.

Legacy: Uniques

Older NFTs minted via the Uniques pallet are also considered PEZ-721 (legacy profile). New collections SHOULD use Nfts.

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Naming & branding conventions

• Always written hyphenated: PEZ-20, PEZ-721 (never PEZ20).
• In wallets/explorers, show a small PEZ-20 / PEZ-721 badge next to the asset, the same way wallets show ERC-20.
• The family is intentionally parallel to the ERC family so the mental model transfers for free: ERC-20 → PEZ-20, ERC-721 → PEZ-721.
• Reserved for future use: PEZ-1155 (multi-token / semi-fungible) if a combined fungible+NFT pallet is adopted. Not active today.

Worked example

A community token "Bereketli Points" issued on Asset Hub:

• Registered in Assets with Asset ID N, symbol: BRP, decimals: 2.
• Issuer set to the program treasury; admin can freeze on abuse.
• Wallets display it as BRP · PEZ-20.
• Transfers use assets.transfer(N, …); allowances use assets.approve_transfer / assets.transfer_approved.

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This document defines a naming and interface convention only. It introduces no new runtime code and requires no chain upgrade — PEZ-20 and PEZ-721 describe the pallet-assets and pallet-nfts interfaces that already exist on Pezkuwi Asset Hub.