CrossMeter

Integrating crypto payments today is messy — developers juggle chain-specific SDKs, figure out bridging, and spend days patching together infrastructure that should really “just work.” We built a billing infrastructure that abstracts all that into a single API key and a few lines of code.

At its core, our system relies on PayPal’s PYUSD and Circle’s multichain USDC swaps as the settlement rails. This means that no matter which chain a customer decides to pay from, the vendor reliably receives stablecoins on their preferred destination chain. The complexity of bridging and routing is handled invisibly in our backend.

For authentication and wallet management, we integrated Dynamic.xyz. Vendors and customers interact with our app without ever exposing private keys, while our system handles signature verification and secure session management under the hood. This enables non-custodial login, wallet identity, and transaction signing without burdening developers with security plumbing.

On top of this foundation, we deliver Billing-as-a-Service. Vendors sign up through our web dashboard, define what they want to charge (one-time, subscription, or usage-based), and instantly receive an API key. That key powers our billing SDK — a lightweight integration where payments, invoices, and analytics flow seamlessly into our platform. All transactions are logged and surfaced in an intuitive dashboard, so vendors can see revenue, subscription activity, and payment success rates without touching chain explorers or custom scripts.

The result: developers integrate payments in minutes instead of weeks, their users pay from any chain they prefer, and settlement lands exactly where the vendor wants it. We abstract away the hardest parts of crypto payments, delivering what we call a true “single-line billing infra” for stablecoin transactions.

Integrating crypto payments today is messy — developers juggle chain-specific SDKs, figure out bridging, and spend days stitching together infrastructure that should really “just work.” Our approach was to collapse all that complexity into a billing platform that runs on stablecoin rails, exposed through a clean SDK and API key.

At the settlement layer, we built on PayPal’s PYUSD and Circle’s multichain USDC swap infrastructure. This lets us accept payments on any supported chain while ensuring vendors always settle in stablecoins on their preferred destination chain. Bridging, routing, and unit conversion (from user-facing cents into chain-specific minor units) are handled entirely in our backend, so developers never need to write swap or bridging logic.

For authentication and wallet management, we integrated Dynamic.xyz. Vendors and customers connect wallets through Dynamic’s UI, and our backend consumes Dynamic-issued JWTs for signature verification and secure sessions. This gave us non-custodial login, wallet identity, and transaction signing without ever touching raw private keys.

On top of this foundation, we deliver Billing-as-a-Service. A vendor registers through our web dashboard, sets their wallet address (where they’ll receive all funds), and defines products with chosen billing models — one-time, subscription, or usage-based. Once configured, the vendor gets an API key, which powers our lightweight billing SDK. Using just a vendor ID + product ID, they can spin up fully functional payments inside their app with a few lines of code.

Here’s how the flow works under the hood:

• The vendor requests a new charge → our backend generates a payment_intent.
• The customer hits the transaction interface, sees how much they’ll pay and where it’s headed, then chooses the chain they want to pay from.
• The transaction is executed and attestations (success/fail, tx hashes) are posted back to our backend.
• We record the final state of the transaction, including both source and destination tx hashes, and mark the payment as settled.
• This information syncs back into the vendor dashboard, where they can track revenue, adjust pricing, or review subscription activity — all without ever opening a block explorer.

From a stack perspective:

• Backend: FastAPI + Postgres, deployed on Render + Supabase
• Frontend: Next.js + Dynamic.xyz
• Smart Contracts: Solidity, Circle swap + PayPal PYUSD