Meta API

Browser-compatible meta-transaction client for AzothPay Gasless UX for subscriptions, payments, deposits & withdrawals – powered by EIP-712 and a relayer network.

✅ No axios – uses native fetch()

✅ Full EIP-712 signing (ethers-compatible)

✅ Non-custodial: user signs off-chain, relayer broadcasts on-chain

✅ Works in modern browsers and bundlers (Webpack, Vite, etc.)

---

📦 Installation & Initialization

npm install @azothpay/api ethers

import { AzothPayMetaApiClient } from '@azothpay/api/browser';

const metaClient = new AzothPayMetaApiClient(
  'https://azothpay.com',     // production endpoint
  'bsc-usdt',                 // 'bsc-usdc' | 'bsc-usdt' | 'pol-usdc'| 'pol-usdt'
  'your-api-key'              // issued after KYB and onboarding
);

Constructor Parameters

Param	Required	Description
baseUrl	✅	API base URL, e.g. 'https://azothpay.com'
contract	❌	Contract identifier: 'bsc-usdc' | 'bsc-usdt' | 'pol-usdc'| 'pol-usdt'
apiKey	✅	API key (issued by AzothPay during onboarding)
provider	❌	Optional ethers.Provider, can be set later via .setProvider()

🔐 All requests automatically include the header: x-api-key: <your-api-key>

---

🔑 Meta-Transaction Concept in AzothPay

Meta-transactions allow users to perform operations without paying gas themselves:

1. Client → API: call prepare*MetaTransaction(...) → get structured transactionData

2. Client → Wallet: call signMetaTransaction(...) → sign EIP-712 message with traits

3. Client → API: call executeMetaTransaction(...) → relayer submits the tx on-chain

Result: the user does not pay gas; they only pay according to your business logic (subscriptions, payments, etc.). Gas is paid by the relayer, which you or AzothPay control.

---

📚 Method Overview

1. Prepare Meta-Transactions (off-chain)

These methods prepare data for EIP-712 signing and later execution.

Method	Params	Returns
prepareSubscriptionMetaTransaction(params)	{ from, author, subscriptionRate, projectId }	{ from, method, data }	Prepares subscribe(...) call
prepareCancelSubscriptionMetaTransaction(author, params)	author, { from }	{ from, method, data }	Prepares unsubscribe(author) call
preparePaymentMetaTransaction(params)	{ from, to, amount }	from, method, data }	Prepares pay(to, amount) call
prepareDepositMetaTransaction(params)	{ from, amount, isPermit2? }	{ from, method, data }	Prepares deposit(amount, isPermit2) call
prepareWithdrawMetaTransaction(params)	{ from, amount, to? }	{ from, method, data }	Prepares withdraw(amount) or withdrawTo(to, amount) call

📌 amount and subscriptionRate in token smallest units (wei-like). For USDT/USDC (18 decimals), multiply USD amount by 1e18: 50 USDT → '50000000000000000000'. 📌 amount in prepareDepositMetaTransaction() in token should be same as for native token. example: USDT on Polygon (6 decimals), multiply USD amount by 1e6: 50 USDT → '50000000'.

---

2. Signing (client-side, EIP-712)

signMetaTransaction(transactionData, signer, contractAddress, chainId, relayerAddress)

Signs prepared meta-transaction using EIP-712.

Param	Type	Description
transactionData	object	Result of any prepare*MetaTransaction() call
signer	ethers.Signer	Ethers signer, e.g. provider.getSigner() from MetaMask
contractAddress	string	AzothPay contract address (0x...)
chainId	number	Chain ID (e.g. 137 for Polygon)
relayerAddress	string	Address of the relayer (operated by you or AzothPay)

Returns:

{
  from: string;
  data: string;      // JSON string, e.g. { "data": "0x..." }
  nonce: number;
  signature: string; // EIP-712 signature
  deadline: number;  // unix timestamp
}

---

3. Execute Meta-Transaction (via relayer)

executeMetaTransaction(signedTransaction)

Sends signed meta-transaction payload to the relayer API. The relayer then broadcasts the corresponding on-chain transaction.

Returns (typical):

• txHash: transaction hash after broadcast

• status: 'pending' | 'confirmed' | 'failed'

• On error – HTTP 4xx/5xx with error description

⚠️ The relayer must be authorized in the AzothPay contract.

Contact AzothPay if you want to use the shared relayer or run your own.

---

🚀 Convenience “All-in-One” Methods

These helpers encapsulate: prepare → sign → execute.

Method
createSubscriptionViaMetaTransaction(params, signer, contractAddress, chainId, relayerAddress)	Gasless subscription creation
cancelSubscriptionViaMetaTransaction(author, params, signer, contractAddress, chainId, relayerAddress)	Gasless subscription cancellation
makePaymentViaMetaTransaction(...)	Gasless one-off payment
depositFundsViaMetaTransaction(...)	Gasless deposit
withdrawFundsViaMetaTransaction(...)	Gasless withdraw

Example: Gasless Subscription

import { ethers } from 'ethers';
import { AzothPayMetaApiClient } from '@azothpay/api/browser';

const provider = new ethers.providers.Web3Provider(window.ethereum);
const signer = provider.getSigner();
const [account] = await provider.listAccounts();

const metaClient = new AzothPayMetaApiClient(
  'https://azothpay.com',
  'pol-usdt',
  'your-api-key'
);

const result = await metaClient.createSubscriptionViaMetaTransaction(
  {
    from: account,
    author: '0x742d35Cc6634C0532925a3b8D4C9f2a93A9E3F1A',
    subscriptionRate: '50000000000000000000', // 50 USDT (18 decimals)
    projectId: 0
  },
  signer,
  '0x8F7d7e3F56c3A71E4f3B58A0E77a0A873c52bF05', // AzothPay USDT contract
  137,                                           // Polygon
  '0xD9147F139980cFcB552Fcae2f3c9b7B215ACE850'  // Relayer address
);

console.log('Meta tx sent:', result.txHash);

---

🔁 Additional Methods

Method	Description
getNonce(address)	Returns the current nonce for given address (for replay protection)
setProvider(provider)	Sets/updates ethers.Provider (useful to fetch chainId etc.)

---

⚠️ Important Notes

1. Relayer security

   Only trusted relayers should be allowed to execute meta-transactions.

   AzothPay can provide a shared relayer or help you deploy your own.

2. Signature deadline

   Each meta-transaction has a deadline (unix timestamp). After that time, the contract rejects the signature.

3. Replay protection

   Contracts validate (nonceType, nonce) pairs – each combination is unique and can be used only once.

4. EIP-712 support

   Wallet must support eth_signTypedData_v4 (MetaMask, WalletConnect, Coinbase Wallet, etc.).

---

🛡️ Security & Compatibility

• ✅ Supports ethers.js v5 and v6

• ✅ Uses native fetch() only (no axios)

• ✅ Compatible with modern bundlers (Webpack, Vite, etc.)

• ✅ Relies on BigInt – runtime will check for availability

• ✅ Default HTTP timeout: 10 seconds for API calls

---

💡 AzothPay is non-custodial, audited, and stablecoin-native infrastructure for: adult, iGaming, VPN, donations.