Cryptocurrency Payment Gateway Development

I need a seasoned blockchain developer to build a robust cryptocurrency-based payment gateway for an upcoming project. The gateway must let online merchants accept and settle payments directly in crypto, handle real-time confirmations on-chain, and expose a clean REST/JSON API so that checkout pages (web and mobile) can call a single endpoint to create, query, and confirm transactions.

Here’s what I’m after:

• Core service that listens to the chosen blockchain network, generates unique deposit addresses per order, watches for confirmations, and notifies my platform with webhooks.
• Secure key management: hot wallet for automated payouts, cold-wallet sweep logic configurable by threshold.
• Dashboard (simple but functional) where I can view live and historical transactions, resend callbacks, and set fees.
• Clear developer documentation and sample code snippets in JavaScript or Python so my front-end team can integrate quickly.
• Dockerised deployment scripts plus instructions for running the nodes and the service on Ubuntu.

Acceptance criteria
1. End-to-end test: create a payment request, broadcast a real transaction on testnet, receive webhook after the required confirmations, and see the status update in the dashboard.
2. Code passes static security scan and basic unit tests.
3. All external dependencies are listed with their OSS licences.

If you’ve previously shipped a crypto payment processor, especially one written in Node.js, Go, or Rust, your experience will be invaluable. Let’s talk about the chain(s) you prefer working with and any existing libraries we can leverage to accelerate delivery.