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Support

A tiered support system on the world computer.

Support is a minimal contract for recurring ETH-based patronage. Supporters choose a tier, pay in ETH (priced via Chainlink USD oracle), and receive a tradeable ERC-721 NFT representing their subscription. Subscriptions can be upgraded, downgraded, extended, or gifted. The NFT carries fully on-chain SVG metadata built dynamically from the subscription state.

Contract

The core is Support.sol, an abstract contract extended by SupportToken.sol which adds ERC-721 token representation via WithSupportTokens.

support

Subscribe an address at a given tier for a number of months. The payer (msg.sender) pays; the subscription and NFT go to the recipient. Third parties can extend or start subscriptions, but only the recipient (or owner) may change tiers.

function support(address recipient, uint8 tier, uint32 duration) external payable

Prices are set in USD and converted to ETH at the current Chainlink rate. Excess ETH is refunded.

grant

Owner can grant free subscriptions with an optional custom start time.

function grant(address recipient, uint8 tier, uint32 duration, uint64 startAt) external onlyOwner

estimate

Get the ETH cost and adjusted duration for a given tier, duration, and supporter (accounts for hooks).

function estimate(uint8 tier, uint32 duration, address supporter) external view returns (uint256 ethCost, uint32 adjustedDuration)

Subscriptions

Each subscription has a unique ID. An address can only have one active subscription at a time, tracked by subscription[address].

Subscription data is stored per ID:

struct SubscriptionData {
    uint64 createdAt;
    uint64 startedAt;
    uint64 expiresAt;
}

Tier changes are recorded as a history of TierPeriod { tier, startedAt } segments.

Tier Changes

• Same tier: extends the expiry. No new segment.
• Upgrade: tier switches immediately. Remaining time is converted at the rate ratio (remaining * oldPrice / newPrice), then new duration is added. If the result is under 30 days, extra is charged to guarantee the minimum.
• Downgrade: tier switches immediately. Remaining time converts to more time at the lower rate. duration = 0 is valid for a pure tier switch with no extension.

Gifting

Anyone can gift a subscription or extension by passing a different recipient to support(). Third parties can only extend at the same tier — only the recipient or owner may change an active subscription's tier.

NFT

A standard ERC-721 is minted on first support (one per wallet via OnePerWallet). Tokens are fully transferable — the subscription travels with the NFT. When transferred, the sender loses the active subscription and the receiver inherits it. After a subscription expires, calling support() again mints a new NFT — the old one stays in the wallet as a historical record.

Token metadata is fully on-chain via a pluggable ISupportRenderer. The default SupportRenderer generates a data:application/json;base64 URI with a dynamically built SVG showing the project name, supporter address, tier badge, subscription status, and duration.

ERC-4906 MetadataUpdate is emitted on every subscription change so marketplaces refresh.

Hooks

Subscription behavior can be customized via the ISubscriptionHook interface, set with setHook(). Hooks can adjust pricing, duration, start time, block subscriptions, and react to tier changes.

interface ISubscriptionHook {
    function beforeSubscribe(uint8 tier, uint32 duration, uint256 baseUSD, address supporter, bool isNew, uint8 previousTier) external view returns (Adjustments memory);
    function canSubscribe(uint8 tier, address supporter) external view returns (bool);
    function onSubscribe(uint8 tier, address supporter) external;
    function onRelease(uint8 tier, address supporter) external;
}

Built-in hooks:

Hook	Description
DiscountHook	Configurable bulk discount (min months + percent off)
MaxSlotsHook	Limits active subscribers per tier
EvmNowSupporterHook	20% discount for 12+ months, blocks partner tier

Owner Functions

Function	Contract	Description
setTierPrice(tier, priceUSD)	Support	Update a tier's monthly USD price
addTier(priceUSD)	Support	Add a new tier
setHook(hook)	Support	Set the subscription hook (address(0) to disable)
withdraw()	Support	Withdraw all collected ETH
setLogo(logo)	WithSupportTokens	Update the logo SVG content
setRenderer(renderer)	WithSupportTokens	Update the metadata renderer contract
transferOwnership(newOwner)	Support	Transfer contract ownership (two-step)

Events

event Supported(address indexed supporter, uint8 indexed tier, uint256 indexed subscriptionId, uint32 duration, uint256 paid, uint64 startedAt, uint64 expiresAt)
event TierPriceUpdated(uint8 indexed tier, uint128 priceUSD)
event HookUpdated(address hook)
event Withdrawal(address indexed to, uint256 amount)
event MetadataUpdate(uint256 tokenId)

Packages

Monorepo managed with pnpm workspaces.

Package	Description
packages/contract	Solidity contract, tests, and deployment
packages/indexer	Ponder-based indexer for subscriptions and events

Contract

Built with Hardhat 3 and viem.

cd packages/contract
npx hardhat test

Indexer

A Ponder indexer that watches Supported and Transfer events, maintaining a queryable database of supporters, subscriptions, and events. Exposes GraphQL and SQL APIs.

Setup

pnpm install

License

MIT