Smart Contracts

useContent uses two smart contract managers:

• SubscriptionManager for reader-to-author subscriptions;
• PlatformSubscriptionManager for author-to-platform billing and storage quota payments.

Both contracts are deployed per supported EVM network and discovered by the backend through the deployment registry. Current runtime configuration includes test networks such as Sepolia, Base Sepolia, Optimism Sepolia and Arbitrum Sepolia, plus production-oriented chain ids for Base, Optimism and Arbitrum.

SubscriptionManager

The contract supports native token payments and ERC-20 payments. For ERC-20 plans, the reader approves the manager contract before calling subscribe. For native token plans, the reader sends msg.value with the subscription transaction.

The important contract state is intentionally small: registered plans and paidUntil by subscriber and plan key. Rich product state such as comments, access policy names, tier descriptions and content metadata remains off-chain.

Reader payment verification

The backend checks the manager address, subscriber wallet, plan key, token, amount and paid-until value before updating MongoDB.

PlatformSubscriptionManager

This contract does not split revenue with creators. It represents author-to-platform billing: plan tier, extra storage and paid-until state.

Contract responsibilities

SubscriptionManager
Reader pays an author plan. The contract stores plan data and paid-until state, splits payment between author and platform treasury, and emits `SubscriptionPaid`.

PlatformSubscriptionManager
Author pays the platform for a tier and extra storage. The contract transfers the full amount to the treasury and emits `PlatformSubscriptionPaid`.

Native vs ERC-20 payments

Payment type	User action	Contract behavior
Native token	Call payable subscribe with msg.value	Contract validates the sent value and transfers native funds.
ERC-20 token	Approve manager, then call subscribe	Contract uses transferFrom to move tokens.

Reader subscription plans may accept native token or ERC-20 payments depending on the author configuration. Platform billing v1 uses ERC-20 payment flow because author billing needs predictable pricing semantics for tiers and extra storage.

Backend confirmation rules

The backend validates contract events before updating MongoDB. It checks:

• manager address from the deployment registry;
• subscriber or author wallet;
• plan key or platform tier key;
• token address and amount;
• chain id and transaction hash idempotency;
• paid-until timestamp emitted by the contract.

This makes MongoDB an operational projection of verified on-chain events rather than a source of payment truth.

Deployment

Contracts are deployed through manual GitHub Actions workflows. This keeps private deploy keys and RPC configuration outside runtime application containers.

The deployed manager addresses are synced to the backend registry so the application can resolve the active manager per chain.