Search
K

Payments

Overview

The Payments module facilitates commerce within games. Developers can effortlessly process payments in a variety of ERC-20 currencies that leverage equivalent exchange rates for smooth transactions. For example, the payments module is used to define the cost of an asset to be, for example, the MAGIC equivalent of 10 USDC.

Key Features

  1. 1.
    In-game Commerce Support: The Payments module facilitates commerce within games, allowing developers to integrate a dynamic and engaging economy system within their gaming universe.
  2. 2.
    Effortless Payments Processing: Developers can easily process payments using the Payments module. It streamlines the usually complex process and allows for efficient and seamless transactions.
  3. 3.
    Multiple Currency Support: The module supports a variety of ERC-20 currencies, accommodating a diverse range of users and transactions. This feature broadens the scope of in-game purchases, making it more accessible for players around the globe.
  4. 4.
    Equivalent Exchange Rates: To ensure smooth transactions, the Payments module leverages equivalent exchange rates. This feature ensures fairness and consistency in transactions, making the trading process transparent and reliable.
  5. 5.
    Asset Pricing: The Payments module allows developers to define the cost of an asset in terms of another currency. This feature provides a flexible pricing mechanism that can cater to a wide range of pricing scenarios.
  6. 6.
    Flexibility and Adaptability: The Payments module allows developers to adapt to changing market conditions by adjusting asset prices or introducing new currencies. This flexibility allows for continual adaptation and improvement, ensuring the in-game economy remains engaging and dynamic.

Integration Guide

  1. 1.
    The process of configuring a payment starts by calling a method on the game development suite. The method called depends on the payment currency and the currency used to determine the value.
The methods are:
  1. 1.
    makeStaticGasTokenPayment: Accepts payment in ETH (gas token) with the price also in ETH. For instance, if you want exactly 1 ETH.
  2. 2.
    makeStaticERC20Payment: Takes payment in an ERC20 token, which is a flat amount. For example, if you want exactly 10 $MAGIC.
  3. 3.
    makeGasTokenPaymentByPriceType: Receives payment in ETH (gas token), priced in another currency. For instance, if you want ETH equivalent to $10 USD.
  4. 4.
    makeERC20PaymentByPriceType: Accepts payment in an ERC20 token, priced in another currency. For example, if you want $MAGIC equivalent to $10 USD.
These conversions are powered by ChainLink's Price Feeds. Currently, our game development suite supports the following feeds:
  • $MAGIC <-> USD
  • $ARB <-> USD
  • ETH <-> USD.
If you want us to add another currency supported by ChainLink, please contact us via Discord or at [email protected].
  1. 2.
    To receive payments with the payment module, you need to deploy a contract for your project that implements the IPaymentsReceiver.
IPaymentsReceiver has two key methods: acceptERC20 and acceptGasToken. These methods should verify all received parameters (price, token, etc.), and also act on the payment (like minting the user's NFT, emitting an event for external services to acknowledge the payment, recording the payment in the receiver contract, etc.). If you won't use a specific payment type, the method can revert safely.
An example of IPaymentsReceiver is available via PaymentsReceiver. You can inherit directly from this contract or use it as a guide to create your own.

Technical Cheat Sheet / Quick Reference

NOTE: See Relevant Contract Addresses for the correct contract addresses to use for tokens / Payments Module. All addresses below will reflect Arbitrum Mainnet

Calculating Payment Amounts

Get $10 USD worth of MAGIC: calculatePaymentAmountByPriceType(0x539bdE0d7Dbd336b79148AA742883198BBF60342, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Example cast: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" 0x539bdE0d7Dbd336b79148AA742883198BBF60342 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc
Example cast formatted (assumes you have bc command): echo "scale=18; $(cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" 0x539bdE0d7Dbd336b79148AA742883198BBF60342 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc | awk '{print $1;}') / 1000000000000000000" | bc
Get $10 USD worth of ARB: calculatePaymentAmountByPriceType(0x912CE59144191C1204E64559FE8253a0e49E654, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Get $10 USD worth of ETH: calculatePaymentAmountByPriceType(0x0000000000000000000000000000000000000000, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Example cast: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" 0x0000000000000000000000000000000000000000 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc
Example cast formatted (assumes you have bc command): echo "scale=18; $(cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" 0x0000000000000000000000000000000000000000 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc | awk '{print $1;}') / 1000000000000000000" | bc

Making Payments

For these I will use a dummy contract address (0x1337000000000000000000000000000000001337) that is assumed to implement the IPaymentsReceiver interface and otherwise be a valid receiver.
For the example casts I will use a dummy bob address (0x0000000000000000000000000000000000000b0b)
Make a 10 $MAGIC payment: makeStaticERC20Payment(0x1337000000000000000000000000000000001337, 0x539bdE0d7Dbd336b79148AA742883198BBF60342, 10000000000000000000)
Example cast: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "makeStaticERC20Payment(address,address,uint256)" 0x1337000000000000000000000000000000001337 0x539bdE0d7Dbd336b79148AA742883198BBF60342 10000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc --from 0x0000000000000000000000000000000000000b0b --trace --verbose
Make a MAGIC payment equal to $10 USD: makeERC20PaymentByPriceType(0x1337000000000000000000000000000000001337, 0x539bdE0d7Dbd336b79148AA742883198BBF60342, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Example cast: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "makeERC20PaymentByPriceType(address,address,uint256,uint8,address)" 0x1337000000000000000000000000000000001337 0x539bdE0d7Dbd336b79148AA742883198BBF60342 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc --from 0x0000000000000000000000000000000000000b0b --trace --verbose
Make an ARB payment equal to $10 USD: makeERC20PaymentByPriceType(0x1337000000000000000000000000000000001337, 0x912CE59144191C1204E64559FE8253a0e49E654, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Make a 0.01 ETH payment (note different function than erc20): makeStaticGasTokenPayment(0x1337000000000000000000000000000000001337, 10000000000000000)
Example cast: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "makeStaticGasTokenPayment(address,uint256)" 0x1337000000000000000000000000000000001337 10000000000000000 --rpc-url https://arb1.arbitrum.io/rpc --value 10000000000000000 --from 0x0000000000000000000000000000000000000b0b --trace --verbose
Make an ETH payment equal to $10 USD (note different function than erc20): makeGasTokenPaymentByPriceType(0x1337000000000000000000000000000000001337, 1000000000, 2, 0x0000000000000000000000000000000000000000)
Example cast (assuming $10 USD is .006 ETH): cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "makeGasTokenPaymentByPriceType(address,uint256,uint8,address)" 0x1337000000000000000000000000000000001337 1000000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc --value 6000000000000000 --from 0x0000000000000000000000000000000000000b0b --trace --verbose

Example CLI Commands

The following are scripts to assist in ensuring your contract is set up correctly and can use the Payments module. It is assumed that you have Foundry/Cast installed.

Check if your contract supports the IPaymentsReceiver interface:

cast call {your_contract_address} "supportsInterface(bytes4)(bool)" 0x298508df --rpc-url {your_network_rpc_url}
NOTE: 0x298508df is the value of type(IPaymentsReceiver).interfaceId
Working example:
cast call 0xb2e806a80D9328b3dC3787313588CE18A44B8653 "supportsInterface(bytes4)(bool)" 0x298508df --rpc-url https://arb1.arbitrum.io/rpc

Check if making a payment through your contract will succeed

  1. 1.
    Get the necessary payment amount if you are pinning your payment to USD/some other second token: cast call {spellcaster_address} "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" {payment_token} {price} {price_type} {priced_token} --rpc-url {your_network_rpc_url} Working example for getting $25 worth of ETH: cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "calculatePaymentAmountByPriceType(address,uint256,uint8,address)(uint256)" 0x0000000000000000000000000000000000000000 2500000000 2 0x0000000000000000000000000000000000000000 --rpc-url https://arb1.arbitrum.io/rpc
  2. 2.
    Use cast call to simulate the makePayment transaction with your preferred payment token. To follow the example in #1 above, I will continue the gas token pinned to USD example (note --value XXXXX must match the output from #1 or you will get IncorrectPaymentAmount: cast call {spellcaster_address} "makeGasTokenPaymentByPriceType(address,uint256,uint8,address)" {your_contract_address} {price} {price_type} {priced_token} --from {your_sender} --value {value_from_step_1} --rpc-url {your_network_rpc_url} --trace --verbose Working example for seeing if an address with sufficient eth can mint a kaiju card pack during their event (will NOT work in the future when minting disabled / eth changes price): cast call 0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194 "makeGasTokenPaymentByPriceType(address,uint256,uint8,address)" 0xb2e806a80D9328b3dC3787313588CE18A44B8653 2500000000 2 0x0000000000000000000000000000000000000000 --from 0x9b56E90e52070e307B66f8777d7FD572cF2FE464 --value 15214238096918503 --rpc-url https://arb1.arbitrum.io/rpc --trace --verbose NOTE: If you get IncorrectPaymentAmount after plugging in the correct value from step #1 you may have hit a price feed update change, rerunning #1 to get the new value will fix this. This is only remotely likely to happen with gas token price feeds as they are more real-time and require precise value matching vs erc20 tokens only taking what is calculated.

Relevant Contract Addresses

Arbitrum Mainnet

Contract
Address
Payments Module
0xF325aC5c9dc74A3c3b7F2474A709154E9F6bc194
MAGIC
0x539bdE0d7Dbd336b79148AA742883198BBF60342
ARB
0x912CE59144191C1204E64559FE8253a0e49E6548

Arbitrum Goerli

Contract
Address
Payments Module
0x366A17839a625b87B114bE0aB5a45A979959702B
MAGIC
0x88f9eFB3A7F728fdb2B8872fE994c84b1d148f65
ARB
0xF861378B543525ae0C47d33C90C954Dc774Ac1F9
Arbitrum Sepolia
Contract
Address
Payments Module
0x06E308c2ED6168AfD158A4B495b084E9677F4E1D
MAGIC
0x55d0CF68a1Afe0932Aff6F36C87eFa703508191C
ARB
N/A
Last modified 1mo ago