Question 1

Does payfjord hold my money?

Accepted Answer

No. You enter your own wallet address and customers pay straight into it. The system only reads public blockchain data to know the money arrived — it has no private key for your wallet, so it could not withdraw anything even if it wanted to.

Question 2

How do you tell which payment belongs to which invoice on a shared wallet?

Accepted Answer

Each invoice gets its own decimal ending. The customer must send exactly that amount — 25.03 rather than 25.00 — and the system matches on that number. That is why the checkout page is so insistent: one wrong digit and it cannot match automatically.

Question 3

What do I need to know about blockchain to use this?

Accepted Answer

Nothing. You need a USDT wallet address and the ability to call an API. Reading the chain, counting confirmations and handling duplicate transactions all happen on our side.

Question 4

How does my website know when a customer has paid?

Accepted Answer

Two ways, either is fine. Pass callback_url when creating the invoice and we send a GET there when it completes. Or keep the trans_id and call /api/GetInvoiceStatus whenever you like. Status has exactly three values: waiting, completed, expired.

Question 5

Where does the customer go after paying?

Accepted Answer

The checkout page remembers where the customer came from and shows a return button on both the success and the expired screen. You can also set it explicitly with return_url, success_url and cancel_url when creating the invoice.

Question 6

I use another gateway — do I have to rewrite anything?

Accepted Answer

Endpoint names, parameter names and JSON field names match FPayment exactly, so in most cases you only change the domain and the API keys.

Question 7

How is the fee calculated?

Accepted Answer

A percentage of the amount actually received, deducted from the credit you topped up, and only when an invoice is genuinely paid.

Question 8

Do expired invoices cost anything?

Accepted Answer

No. Expired invoices, cancelled ones, and unpaid ones are all free.

Question 9

Where does the money go if a customer pays after the invoice expired?

Accepted Answer

It is still in your wallet — it went there directly from the start. The system logs it under unmatched payments with its transaction hash, and you attach it to an invoice in one click. No fee for this, because you did the reconciliation yourself.

Question 10

Do I have to give you my wallet's private key?

Accepted Answer

Absolutely not, and there is nowhere to enter one. All we need is the wallet address — something anyone can look up on a block explorer. If any service asks for your private key, walk away.

Question 11

What about Binance API keys?

Accepted Answer

Enable Reading permission only. Do not enable trading or withdrawal — that way a leaked key still cannot touch your money. The secret is AES-256-GCM encrypted before storage and never shown again.

Frequently asked questions

Basics

Integration

Money

Security

Frequently asked questions

Basics

Integration

Money

Security