Payment Gateway Integration: Stripe, PayPal, Crypto, and Beyond

Payment processing is where hosting billing meets real money. Get it right, and clients pay seamlessly. Get it wrong, and you lose revenue to failed transactions, unsupported currencies, and checkout friction.

Most billing platforms take one of two approaches: they either hardcode a few popular gateways and call it done, or they offer a plugin marketplace where third-party developers build gateway integrations of varying quality and maintenance status.

FluxBilling does something different. Every payment gateway is a visual plugin — a configurable flow built with the same drag-and-drop editor used for provisioning automation. This means gateway behavior is transparent, modifiable, and extensible without writing code.

The Plugin-Based Gateway Architecture

Traditional billing platforms compile payment gateway logic into their core codebase. When Stripe changes their API, you wait for the billing vendor to release an update. When you need a niche regional gateway, you hope someone has written a module for it.

FluxBilling's approach separates gateway logic from the application core:

• Each gateway is a JSON-defined plugin with its own connection settings, flows, and webhook handlers
• The Flow Executor runs gateway operations node-by-node, executing API calls, conditions, and data transforms
• The Gateway Registry manages available gateways with priority ordering, currency support, and capability flags
• Connection management handles authentication, API keys, and mode switching (test/live)

This architecture means adding a new gateway does not require a software update. It requires a plugin definition and its operational flows.

Currently Supported Gateways

Stripe

Stripe is the primary card payment gateway for most hosting providers. FluxBilling's Stripe integration covers the full payment lifecycle:

• Checkout sessions — Redirect clients to Stripe's hosted checkout for PCI-compliant card collection
• Payment intents — Handle the complete payment flow including 3D Secure authentication
• Refunds — Process full or partial refunds directly from the admin panel
• Webhooks — Real-time notifications for payment success, failure, disputes, and refund events
• Multi-currency — Process payments in 135+ currencies using Stripe's native currency support
• Saved payment methods — Clients can save cards for faster future payments
• Test and live modes — Switch between Stripe test and production environments with a toggle

PayPal

PayPal remains essential for clients who prefer wallet-based payments:

• Checkout flow — Redirect to PayPal for payment approval and capture
• Multi-currency — Support for 25+ currencies
• Saved payment methods — PayPal account linking for recurring payments
• Refunds — Full refunds with reason tracking (duplicate, fraudulent, customer-requested)
• Webhooks — Event handling for payment completion, cancellation, and refund processing
• Sandbox mode — Full testing environment with PayPal's sandbox accounts

CoinGate

For cryptocurrency payments, CoinGate provides a bridge between traditional billing and crypto:

• Multiple cryptocurrencies — Accept Bitcoin, Ethereum, Litecoin, and dozens of other coins
• Fiat settlement — Receive payouts in your preferred fiat currency regardless of which crypto the client pays with
• Automatic conversion — No cryptocurrency management required on your end

Additional Gateways

Beyond the core three, FluxBilling supports additional gateways through the visual plugin system:

• 2Checkout — Global payments with localized checkout
• Authorize.net — Card processing popular in North America
• BitPay — Alternative cryptocurrency payment processor
• Mollie — European payment methods (iDEAL, Bancontact, SOFORT)
• Skrill — Wallet-based payments popular in gaming and hosting
• GoCardless — Direct debit payments for recurring billing
• Bank Transfer — Manual bank transfer with invoice matching

More gateways are being added regularly. The visual plugin architecture means new integrations can be built and deployed without waiting for a platform update. If your preferred gateway has an API, it can be integrated.

How the Visual Flow Builder Works

Each gateway operation (create checkout, process webhook, issue refund) is a visual flow:

1. Start node — Triggered by an event (client clicks "Pay", webhook received, admin clicks "Refund")
2. HTTP request nodes — Make API calls to the payment provider with dynamic field mapping
3. Condition nodes — Branch based on API response (success? error? 3DS required?)
4. Transform nodes — Map response data to FluxBilling's internal format
5. End node — Return the result (redirect URL, success confirmation, error message)

For example, a Stripe checkout flow looks like:

1. Start: Client initiates payment
2. HTTP POST: Create Stripe Checkout Session with line items, currency, and success/cancel URLs
3. Condition: Was the session created successfully?
4. Yes: Extract session URL, redirect client
5. No: Log error, show payment failure message

Each node is configurable through the admin panel. If Stripe changes an API endpoint or adds a new parameter, you update the flow directly — no code changes, no waiting for a patch.

Gateway Configuration for Admins

Setting up a payment gateway in FluxBilling:

1. Install the gateway plugin from the visual plugin library
2. Configure connection settings — API keys, webhook URLs, mode (test/live)
3. Set gateway properties — Display name, priority order, supported currencies, transaction limits
4. Test — Process a test payment in sandbox mode
5. Enable — Make the gateway available at checkout

Admins can manage gateway priority to control which options appear first at checkout. For example, you might prioritize Stripe for card payments and show PayPal as a secondary option.

Multi-Currency Gateway Support

Payment gateways and multi-currency billing work together in FluxBilling:

• Each gateway declares which currencies it supports
• At checkout, only gateways supporting the invoice currency are shown
• Currency conversion happens at the billing level, not the gateway level
• Gateway-specific currency formatting is handled automatically

This prevents the common problem where a client in Japan sees a PayPal button, clicks it, and gets an error because PayPal does not support JPY for that merchant account. In FluxBilling, that button simply would not appear.

Webhook Handling

Webhooks are critical for payment reconciliation. When a client pays, the gateway sends a webhook notification to FluxBilling confirming the transaction. FluxBilling's webhook system:

• Verifies signatures — Each gateway's webhook verification is handled in its plugin flow
• Processes events — Payment completed, payment failed, refund issued, dispute opened
• Updates records — Invoices are marked paid, services are activated, and email notifications are sent
• Logs everything — Full webhook payload logging for debugging and auditing

Why Plugin-Based Gateways Matter

The traditional approach to payment gateways creates vendor lock-in. You depend on the billing platform vendor to support your preferred gateway, update it when APIs change, and fix bugs when payments fail.

FluxBilling's visual plugin approach shifts control to you:

• Transparency — You can see exactly what API calls the gateway makes
• Customizability — Modify flow behavior without waiting for a vendor update
• Extensibility — Build integrations for any gateway with an API
• Independence — Your payment processing is not locked to the billing vendor's development roadmap

For hosting providers accepting payments globally, this flexibility is the difference between "we support Stripe and PayPal" and "we support whatever your clients need."Start your free trial to explore the payment gateway system. All gateways are included in every plan at no extra cost.