Add EIP: Subscription-Based Token

EIPS/eip-360.md

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+---
+eip: 360
+title: Subscription-Based Token
+description: access to a service or product that requires recurring payments.
+author: 360 Core <[email protected]>, Robin Rajput (@0xRobinR)
+discussions-to: https://ethereum-magicians.org/t/erc-subscription-based-erc20-token/13964
+status: Draft
+type: Standards Track
+category: ERC
+created: 2023-04-25
+requires: 20
+---
+
+## Abstract
+
+The subscription-based [ERC-20](./eip-20.md) token extends the basic [ERC-20](./eip-20.md) token standard with a `subscribe` and `unsubscribe` function, which allow users to subscribe or unsubscribe from the subscription service. The `subscriptionFee` and `subscriptionFrequency` variables define the cost and frequency of the subscription. The `nextPaymentDate` mapping keeps track of the next payment date for each subscriber.
+
+This EIP also proposes adding `renewSubscription` functions to the token contract, that can be used by token holders to renew their subscription to a service or product that requires recurring payments in the form of the token.
+
+## Motivation
+
+The subscription-based [ERC-20](./eip-20.md) token provides a more flexible and convenient way to manage recurring payments. It can be used for a wide range of services and products that require regular payments, such as subscription-based content platforms, gaming services, and more.
+
+## Specification
+
+### SubscriptionToken
+
+#### subscribers
+
+subscribers list for the subscription
+
+#### subscriptionInfo
+
+struct containing metadata of the subscription, ex, `subscriptionID`, `subscriptionName`, `subscriptionDesc` and `subscriptionTandC`, and many more fields if reqd.
+
+#### subscriptionFee
+
+the fee amount for the subcription
+
+#### subscriptionFrequency
+
+frequency of subscription, interval at which the `subscriptionFee` will be charged.
+
+#### subscribe
+
+function to subscribe toh the subscription
+
+#### unsubscribe
+
+revoke subscription
+
+```solidity
+interface ISubscriptionERC20 {
+ /// @dev map subscribers address, returns address(0) if `idx` is not found
+ /// @param idx: the index of the map values
+ /// @return the address at index `idx` of subscribers
+ function subscribers(uint idx) external view returns (address);
+
+ /// @dev can be extended accorging to the requirements
+ /// @return subscriptionID, and metadata payload provided, may vary
+ function subscriptionInfo() external view returns ( uint, string memory, string memory, string memory );
+
+ /// @dev subscribes to the subscription, can be payable
+ function subscribe() external;
+
+ /// @dev unsubscribe the subscription
+ function unsubscribe() external;
+
+ /// @dev view or pure can be used
+ /// @return the subscription fee
+ function subscriptionFee() external view returns (uint256);
+
+ /// @dev view or pure can be used
+ /// @return get the subscription frequency
+ function subscriptionFrequency() external view returns (uint);
+}
+```
+
+## Rationale
+
+TBD
+
+## Backwards Compatibility
+
+No backward compatibility issues found.
+
+## Security Considerations
+
+Needs discussion.
+
+## Copyright
+
+Copyright and related rights waived via [CC0](../LICENSE.md).