SHKeeper

SHKeeper is a self‑hosted, open‑source cryptocurrency payment processor that functions both as a gateway and a merchant. From a technical standpoint, it exposes a RESTful API that allows developers to generate payment addresses, monitor transactions, and orchestrate payouts across a wide array of blockchains. The core engine is written in Go, chosen for its lightweight runtime, concurrency primitives, and native support for cross‑platform binaries—making it ideal for running inside containers or on bare metal. A PostgreSQL database stores transactional state, user accounts, and configuration; all interactions are secured via TLS and JWT‑based authentication.

• Language & Runtime: Go (1.22+), compiled to static binaries for minimal dependencies.
• Web Framework: net/http with a lightweight router (chi) to keep the service lean and highly testable.
• Database: PostgreSQL 15+, accessed through pgx for high‑throughput, connection pooling, and support for advanced features like JSONB columns.
• Cache & Pub/Sub: Redis is optional; it can cache exchange rates and push transaction events to downstream services.
• Blockchain Interaction: The system uses dedicated RPC clients per coin (e.g., btcd, geth, monero-rpc) or third‑party services (e.g., BlockCypher) to poll for new transactions. Each coin has its own wallet module that abstracts address generation, balance queries, and transaction signing for cold‑wallet payouts.
• Containerization: A Dockerfile is supplied, and the service can be orchestrated via Kubernetes or Docker Compose. The image is small (~60 MB) due to static linking.

SHKeeper is designed for self‑hosting on any Linux server, VPS, or cloud instance. Key requirements:

• CPU & Memory: 1 vCPU and 2 GB RAM are sufficient for a small shop; scale vertically or horizontally by adding replicas behind a load balancer.
• Storage: PostgreSQL requires 10 GB for moderate traffic; use SSDs for low latency.
• Network: Public HTTPS endpoint (TLS termination can be handled by the service or an external reverse proxy).
• Backup: PostgreSQL dumps and wallet key backups should be stored encrypted off‑site.
• Scaling: Stateless API workers can be replicated; stateful components (wallet RPC clients) should use a shared Redis queue to coordinate payouts.

The public API follows RESTful conventions and returns JSON payloads. Developers can:

• Embed payment buttons or QR codes directly into web pages using the /invoice endpoint.
• Consume transaction events via webhooks for automated accounting or CRM updates.
• Leverage the payout API to move funds into cold wallets programmatically, using a secure decryption key that never leaves the server.
• Extend functionality by writing custom plugins that hook into lifecycle events; the open‑source codebase exposes interfaces for adding new coins or payment processors.

• Documentation: Comprehensive API reference (https://shkeeper.io/api/), a knowledge base, and tutorial videos are available. The README includes clear sections on payment flow, API usage, and ready‑made modules.
• Community: The project is hosted on GitHub with an active issue tracker; contributors can submit pull requests for new coins or features.
• Configuration: Settings are driven by a YAML/JSON file and environment variables, allowing CI/CD pipelines to deploy consistent instances.
• Licensing: The source is MIT‑licensed, giving developers full freedom to modify and redistribute.

1. E‑commerce Platforms – Integrate via the WooCommerce or PrestaShop modules to accept crypto payments without additional fees.
2. SaaS Billing – Use the API to generate invoices and auto‑credit overpayments to user balances.
3. Marketplace Operators – Route payments through SHKeeper and automatically split proceeds via the multipayout feature.
4. Financial Services – Build a custodial‑free wallet service that aggregates multiple coins and offers instant payouts to customers.

• Zero Transaction Fees – All payments are processed directly on the blockchain; no intermediary commissions.
• Full Control & Privacy – Self‑hosted architecture eliminates KYC/AML constraints and gives developers ownership of keys.
• High Performance – Go’s concurrency model ensures low latency even under