Frequently Asked Questions

General

What is QuantaPay?

QuantaPay is a non-custodial cryptocurrency payment gateway. It allows businesses to accept Bitcoin, Ethereum, USDT, and 30+ other cryptocurrencies as payment. "Non-custodial" means QuantaPay never holds your funds — payments go directly to your wallet.

How much does it cost?

QuantaPay charges a flat 0.8% fee per successful transaction, deducted from your Credits balance. There are no monthly fees, setup fees, or withdrawal charges.

What is the Credits system?

Credits are your prepaid balance used to cover transaction fees. When a payment is completed, the 0.8% fee is deducted from your Credits. You can check your balance via the dashboard.

Is QuantaPay safe?

Yes. QuantaPay is non-custodial — your funds go directly to your wallet address. We never have access to your private keys or funds. All API communications use HTTPS, and webhooks include a secret key for verification.

Which cryptocurrencies are supported?

QuantaPay supports 30+ cryptocurrencies including:

• Major: BTC, ETH, USDT, USDC, BNB, SOL, TRX
• Altcoins: LTC, DOGE, XRP, BCH, XMR, LINK, SHIB, BAT, ALGO, AVAX, DOT, XLM, XTZ, POL, and more
• Stablecoins: USDT (ERC-20, TRC-20, BEP-20, TON), USDC
• TON: Toncoin and USDT on TON network
• L2 Networks: Ethereum on Base, Arbitrum, Optimism
• Custom Tokens: Add any ERC-20 or BEP-20 token (Pro plan)

What currencies can I price in?

You can set your checkout price in any of 160+ fiat currencies (USD, EUR, GBP, JPY, CNY, etc.). QuantaPay automatically converts to the customer's chosen cryptocurrency using real-time exchange rates.

Payments

How long does a payment take?

Payment speed depends on the cryptocurrency:

• Solana: ~1-2 seconds
• Tron (USDT TRC-20): ~3-10 seconds
• Ethereum / ERC-20: ~30 seconds to 3 minutes
• Bitcoin: ~10-30 minutes (1-3 confirmations)

These times can vary based on network congestion.

What happens if the customer underpays?

By default, underpayments are marked as "underpaid" and not completed. You can enable Accept Underpayments in Settings → Payments → Payment Options to automatically accept slight underpayments.

What is the payment timeout?

Checkout sessions expire after 60 minutes. If the customer doesn't complete payment within this window, the session expires. The customer can create a new session to try again.

Can customers pay with MetaMask?

Yes. Enable the Pay with MetaMask option in Settings → Payments → Payment Options. This adds a MetaMask button on the payment page for Ethereum-compatible cryptocurrencies.

What if the exchange rate changes during payment?

The exchange rate is determined when the customer selects a cryptocurrency on the payment page. The customer has 60 minutes from session creation to complete the payment. If the session expires, a new session with updated rates can be created.

Technical

Why isn't my webhook receiving notifications?

Common causes:

1. Wrong URL — Verify the webhook URL in Settings → Payments → Webhook.
2. Firewall blocking — If using Cloudflare or a WAF, allow the webhook endpoint.
3. HTTPS required — Webhook URLs must use HTTPS.
4. Server error — Check your server logs for 500 errors on the webhook endpoint.
5. Not completed — Webhooks only fire for completed transactions (status C).

Why does my transaction stay "Pending"?

• The customer may not have sent the payment yet.
• The blockchain may be congested, causing slow confirmations.
• The payment amount may not match the expected amount.
• The confirmation count hasn't reached your configured minimum.

Use check-transaction to force a re-check, or wait for the automatic cron check.

What address format should I use?

Can I use QuantaPay on localhost?

You can make API calls from localhost, but webhooks require a publicly accessible URL. Use a tunneling service like ngrok for local development.