Crypto Payment Gateway: An Advantage that is worth adding

How Modern Payment Systems Actually Work

Money is borderless now. If your support keeps hearing the same line: “Do you accept crypto?” — crypto payment gateway fixes that: one more way to pay, under your brand, with the operations you already have.

This piece shows how a crypto payment gateway works across multiple chains, and the advantages of a white-label setup.

Read the full article, where we break down every part of the ready-made crypto payment solution for your business.

Two ways to accept crypto

• Direct acceptance will work if you have a small number of transactions or work with regular clients. But volume increase turns manual checks into mistakes because tracking and reporting are done manually.
• A crypto payment gateway handles the entire payment process for you. It shows customers how much to pay, accepts the payment, and notifies you when it’s completed.

Crypto payments gateway flow in 5 steps

Here is the flow your users will feel and your team will run.

1. Create invoice. Your backend requests an invoice for the order and amount and locks the quote for a predefined period of time.
2. Show the invoice. The page shows payment details. Asset and amount are prefilled.
3. Wait for confirmations. The gateway reads the payment address and marks the invoice paid only when the transaction is confirmed (after N confirmations).
4. Fulfill automatically. Your backend receives a signed notification and flips the order to “paid”. No manual checks.
5. Sweep. Funds are consolidated to your main wallet or to your settlement partner on your schedule. Your finance team stays in control.

How Crypto Payment Gateways Work Across Multiple Chains

Our ready-made solution has two parts:

• The Indexer Core turns raw blockchain data into a clean stream of payment events.
• The Invoices App consumes that stream, updates invoice states in real time, and tells your backend when to fulfill.

Indexer Core:

• Chain RPC. Multiple RPC endpoints feed data; the system rate-limits and health-checks to prevent brief node issues from escalating into incidents.
• Chain Poller. Reads blocks in order, tracks a checkpoint in Redis, and retries with backoff — so progress is predictable and restarts are quick.
• Chain Decoder. Extracts only payment-relevant data — currency, amount, from, to, time, block, txHash — and emits corrections if a reorg happens.
• NATS JetStream. A durable event log that smooths spikes (back-pressure) and supports replay after fixes. Output: one reliable event stream for the business side.

Invoices App.

• REST + SSE. Your backend creates an invoice and gets an address plus a TTL (Time-to-Live). The browser subscribes via SSE and sees states flow “created → pending → confirmed → paid” without polling; extra states include “expired, underpaid, overpaid.”
• Queue Processor. Expires invoices when TTL ends or extends the window on partial payments.
• Transfer Handler. Matches payments to invoices, writes to Postgres, moves state, pushes live UI updates, and triggers signed webhooks so your order flips to “paid” automatically. If a reorg hits before finality, it rolls back to “pending” and promotes the invoice again after sufficient confirmations.
• Postgres. Whenever an invoice crosses a meaningful boundary (e.g., reaches finality), the app triggers webhooks to your backend. Webhooks are idempotent so retries don’t double-fulfill.
• Notifications. Optional bot/alerts for operations and to start settlement workflows.
• Client Management Proxy. Allows to run multiple brands/regions using one solution.

Chain-agnostic

Buyers use different assets on different networks. Your crypto payment gateway should handle that.

For each order, the gateway offers one or more supported assets. The quote is updated for a predefined TTL. The buyer chooses, pays, and sees the progress.

Two non-negotiables:

• Finality before “paid.” If a chain is congested or a reorg happens, the invoice stays in “confirming” until the transaction is actually completed. Any invoice is marked “paid” only after chain finality + N confirmations.
• Fix the rate. The system fixes the payment rate for a predefined period of time. The buyer sees a countdown and pays within that term. If time runs out, the invoice expires, and the buyer can request a new quote in one click. No arguments about “the rate moved.”
• TTL (time-to-live). Every invoice has a timer. It protects the price and the buyer’s expectations. If time runs out, the invoice expires and offers a fresh quote. If a small “test” payment came in on time, the policy can extend the window. This one rule prevents a lot of support tickets.

Addresses

There are two practical address models.

• Per-user address. The easiest way to match invoices and analyze users’ behaviour. However, on chains with high fees, it can be costly to sweep every small balance.
• Rotating pool. Reduces sweeping costs in bursty workloads. The UX must be designed carefully to avoid people paying to “old” addresses and set minimums because dust is not worth moving.

Pick the model per product line. For higher-value carts, per-user works great. For micro-transactions or in-app balances, a pool can save costs.

Security & Settlement

Keep private keys out of the payment core. The core only needs public keys to create addresses. Signatures for outbound transfers happen in a separate process under your control.

Read the full article for a better understanding of security and the benefits for your business of using this ready-made solution.

Integration & Checkout UX

Integration is common: one API call to create invoices, one SSE subscription for status. The modal shows payment details, countdown, and retry logic. Back office gets webhooks and maps “paid, expired, underpaid” to familiar order states. That’s integrating cryptocurrency payment solutions on your website without rebuilding checkout.

Finance & Reporting

A good gateway writes every change to a log your back office trusts:

• Daily totals by asset and chain.
• Fees and spreads so you know the real cost to move and convert.
• Refunds and exceptions that tie back to original invoices.
• Reconciliation that matches wallet balances.

You can export reports without pulling an engineer into a meeting. That saves time and reduces risk.

Edge cases that matter

Real traffic is messy. People overpay or underpay. Chains slow down. Your design should treat these not as “gotchas,” but as normal states.

• “Underpay” becomes a state with a clear policy: accept as paid, request a top-up, or refund, and log the action.
• “Overpay” gets the same treatment, with a partial refund or a credit.
• If a chain is congested, your TTL policy allows creation of a new quote automatically.
• Any invoice is marked “paid” only after chain finality + N confirmations.

White-label solution advantages

A white-label crypto payment gateway gives you control over branding, policy, and change velocity. You can add chains, tune confirmation rules, change TTLs, and update sweep thresholds. And because the core is modular, you can put your risk controls where they matter.

About Rock’n’Block

Rock’n’Block is a Web3-native development company. We build crypto payment systems end-to-end: a white-label, self-hosted gateways that give businesses full control over the process, without third-party delegation and no extra commissions.

We’ve contributed to over 300 projects that collectively reached 71M+ users, raised $160M+, and hit $2.4B+ in peak market cap. Our role is to handle the backend complexity so teams can move faster and ship with confidence.

We ♥️ Development

Rock’n’Block