Plugins and links / FOSSBilling

FOSSBilling

Adds Mintage Pay as a payment gateway for FOSSBilling invoices. The client pays in USDC or USDT on the Mintage Pay payment page, the money goes straight to your own wallet, and the invoice is marked Paid by itself when the payment is final.

What you need

FOSSBilling 0.8 or later.
File access to the FOSSBilling folder, and an admin who can manage payment gateways.
FOSSBilling reachable on public https, so Mintage Pay can send it payment updates.
Invoices in a currency Mintage Pay supports: USD, EUR, GBP, CAD, AUD, CHF, JPY, MXN, BRL, INR, SGD, AED, PLN, SEK, NOK, DKK, NZD, ZAR, TRY, KRW, HKD, NGN, ARS, PHP, IDR, VND, PKR, EGP, BDT, KES, GHS, TZS, COP, CLP, PEN, UYU, PYG, BOB, DOP, GTQ, CRC, THB, MYR, TWD, LKR, NPR, KZT, UAH, ILS, SAR, QAR, CZK, HUF, RON, ISK, XAF or XOF. A client in another currency sees a message asking them to choose another method. Clients always pay in US dollar stablecoins: a price in another currency is converted when the payment is started.
A Mintage Pay account with at least one payout address set.

Install

Download mintagepay-fossbilling.zip and unpack it.
Copy its library folder into your FOSSBilling folder, merging it with the library folder already there. This must exist afterwards: library/Payment/Adapter/MintagePay/MintagePay.php.
In FOSSBilling, go to System > Payment gateways, open New payment gateway and install MintagePay.
In the Mintage Pay dashboard, open Developers > API keys and create a key. Copy it: it is shown only once.
In the same dashboard, open Developers > Webhooks, add an endpoint with this address and copy its signing secret:
```
https://<your FOSSBilling address>/ipn.php?gateway_id=<the gateway's ID>
```
The gateway's ID is the number in its edit link in System > Payment gateways.
Edit the gateway in FOSSBilling: paste the API key and the Webhook signing secret, tick Enabled and Allow one time payments, and save.

Try it first with test money

Create a free account at sandbox.mintagepay.com, set a payout address, and create a key (it starts with mp_test_) and a webhook endpoint there.
Put the sandbox key and its webhook secret in the gateway, and save.
Create an invoice for a test client, for example 1.00 USD.
Open the invoice as the client, click the Mintage Pay tile, then Pay Now. You land on a payment page with a Test mode banner.
Pay with free test money: the payment page has a button to get some.
Within a minute or two the invoice is Paid, and Invoices > Transactions shows the payment as processed.
When you are happy, put your live key and the live endpoint's secret in the gateway.

What you will see

What happened	In FOSSBilling
The client paid in full	The invoice is Paid. The transaction note says "Paid with Mintage Pay" and the payment's reference.
Paid only in part, or not yet final	The invoice stays unpaid; the transaction shows the payment's status.
The invoice was edited after the client started paying	The transaction shows an error: the amount paid and the new total. Credit the client by hand.
The same payment update arrives twice	It is credited once.
An update that is not signed with your secret	Refused; nothing changes.

Good to know

A second click on Pay Now reuses the same payment, so a client never pays twice by mistake.
Each payment is tied to its FOSSBilling invoice by the invoice's own random reference, so a staging and a live FOSSBilling on one Mintage Pay key never mix up invoices.
Refunds are made from the Mintage Pay dashboard; record them in FOSSBilling yourself.
Subscriptions (automatic renewals) are not supported yet: renewal invoices are paid one by one.

Last updated 25 October 2026. This page as Markdown. Something missing or wrong? Write to hello@mintagepay.com.