Payment Infrastructure

Complete Payment Infrastructure for USDT

Everything you need to accept USDT payments. Non-custodial by design, deterministic by nature.

Overview

What is a non-custodial USDT payment gateway?

q8qpay is a non-custodial USDT payment gateway: it lets a business accept USDT payments without q8qpay ever taking custody of the funds. Merchants connect their own USDT wallet addresses for the Tron (TRC20), Ethereum (ERC20), or BNB Smart Chain (BSC) networks. When a customer pays, USDT moves directly from the customer's wallet to the merchant's wallet — q8qpay never stores private keys, never holds a merchant's funds, and never initiates a transaction on the merchant's behalf. Its role is limited to watching the blockchain for the incoming transfer, verifying it matches the invoice exactly (network, address, and amount to four decimal places, within the expiry window), and sending the merchant an HMAC-SHA256-signed webhook confirming payment. Because funds never pass through q8qpay's own accounts, a merchant's money is never exposed to the gateway's downtime, security incidents, or insolvency.

Comparison

Non-custodial vs. custodial payment gateways

The difference is who controls the money. With a custodial gateway, funds land in the provider's accounts first; with q8qpay, they never do.

Aspect	Custodial gateway	q8qpay (non-custodial)
Who holds funds	The provider, until payout	The merchant — funds arrive directly in your wallet
Private keys	Held by the provider	Never stored or requested
Counterparty risk	Provider downtime or insolvency can freeze funds	None — money never touches the gateway
Payout delay	Withdrawal/settlement window	Instant — the payment is the payout
Supported assets	Often many tokens	USDT only, on TRC20, ERC20, and BSC

Networks

USDT networks compared: TRC20 vs. ERC20 vs. BSC

q8qpay accepts USDT on three networks. They differ in address format, decimal precision, and how many confirmations q8qpay waits for before marking a payment final.

Network	Chain	Address format	Decimals	Confirmations
TRC20	Tron	Starts with “T”, 34 characters	6	20
ERC20	Ethereum	Starts with “0x”, 42 characters	6	12
BSC	BNB Smart Chain	Starts with “0x”, 42 characters	18	15

Same asset (USDT), same exact-match rules on every network — only the underlying chain differs.

Core Architecture

Non-Custodial By Design

Your funds never touch our servers. We watch the blockchain, match payments, and notify you. That's it.

No Private Keys

We never ask for or store your wallet private keys. You maintain full control.

No Fund Holding

Payments go directly to your wallet addresses. No intermediary accounts.

No Transactions Initiated

We only read blockchain state. We never send transactions on your behalf.

Architecture Overview

Your Customer

Sends exact USDT amount

Blockchain (Direct)

TRC20 / ERC20 / BSC

Your Wallet

Funds arrive directly

We watch the blockchain and send you a webhook when payment is confirmed. We never touch your funds.

Payment Matching

Exact Match Invoice System

No guesswork. No partial payments. Every condition must match exactly for an invoice to confirm.

Network Match

Payment must be on the same network as the invoice (TRC20, ERC20, or BSC)

Address Match

Payment must go to the exact wallet address specified in the invoice

Amount Match

Amount must match exactly to 4 decimal places. No rounding tolerance.

Time Match

Payment must arrive before invoice expiry. Configurable from 5 min to 2 hours.

What We Don't Do

No underpaid invoice acceptance
No overpaid invoice handling
No fuzzy amount matching
No guessing which invoice a payment belongs to

Why This Matters

Deterministic, auditable payment records
No manual reconciliation needed
Eliminates payment disputes
Clear audit trail for compliance

Network Support

Three Networks, One Integration

Let customers pay with USDT on their preferred blockchain. Same API, same webhooks, same experience.

USDT TRC20

Tron Network

Lowest transaction fees
Fast block confirmation
Highest USDT volume

Address format: T... (34 characters)

USDT ERC20

Ethereum Network

Most established network
Highest security
DeFi ecosystem access

Address format: 0x... (42 characters)

USDT BSC

Binance Smart Chain

Low fees like TRC20
EVM compatible
Binance ecosystem

Address format: 0x... (42 characters)

Invoice Management

Complete Invoice Lifecycle

From creation to confirmation. Every state is tracked, logged, and available via API.

Pending

Invoice created, awaiting payment. Customer sees payment page with countdown.

— Configurable expiry (5 min - 2 hours)
— Real-time countdown on payment page
— Auto-polling for status updates

Confirmed

Payment detected and matched. Webhook sent to your callback URL.

— Transaction hash recorded
— Webhook with payment details
— Immutable confirmation

Expired

No valid payment received before expiry. Invoice closed.

— Automatic status update
— Amount released for reuse
— Customer can start new payment

Notifications

Reliable Webhook Delivery

HMAC-signed webhooks with automatic retries ensure you never miss a payment confirmation.

HMAC-SHA256 Signatures

Every webhook is signed with your unique webhook_secret. Verify authenticity before processing.

Exponential Backoff Retries

Failed deliveries retry automatically: 30s, 1m, 2m, 4m... up to 10 attempts.

Full Delivery Logs

View every webhook attempt: status codes, response bodies, retry schedules. Debug with confidence.

Webhook Verification

const crypto = require('crypto');

function verifyWebhook(payload, signature, secret) {
  const expected = crypto
    .createHmac('sha256', secret)
    .update(JSON.stringify(payload))
    .digest('hex');

  return signature === expected;
}

// In your webhook handler
const sig = req.headers['x-webhook-signature'];
if (!verifyWebhook(req.body, sig, WEBHOOK_SECRET)) {
  return res.status(401).send('Invalid');
}

Administration

Full Visibility Admin Dashboard

Monitor everything. Invoices, transactions, webhooks, merchants. All in one place.

Dashboard Overview

Real-time stats: total volume, active invoices, success rates, recent activity.

Invoice Browser

Search, filter, and view all invoices. Check status, amounts, expiry times.

Transaction Logs

Every blockchain transaction detected. Hash, address, amount, confirmations.

Webhook Logs

Every webhook attempt logged. Status codes, payloads, retry schedules.

Merchant Management

View merchants, suspend accounts, manage access. Full control.

System Configuration

Adjust limits, expiry defaults, network settings. All configurable.

Ready to Get Started?

Create your free account and start accepting USDT payments in minutes.

Start Free Read Documentation