Flash Infrastructure

Learn about the technical architecture powering Flash's Bitcoin, Lightning, and NOSTR capabilities

How Flash Works Under the Hood

Flash combines open-source technologies to create a seamless financial application. This page explains the technical infrastructure powering Flash.

Core Technology Stack

1. Bitcoin Core Integration

Flash connects to the Bitcoin network through:

  • Bitcoin Core nodes for blockchain validation
  • Electrum Server for efficient data access
  • Address indexing for fast balance lookups

This provides on-chain Bitcoin functionality with self-custody withdrawals, transaction verification, and deposit detection.

2. Lightning Network Implementation

Flash uses LND for Lightning functionality:

  • LND nodes provide core Lightning capabilities
  • Custom middleware manages channel liquidity

Enabling instant payments, sub-cent micropayments, and cross-border transactions.

3. NOSTR Protocol Integration

Flash incorporates NOSTR via:

  • Multiple relay connections for censorship resistance
  • Client-side key management for identity control
  • End-to-end encryption for private messages

Powering direct messaging, group chats, and business communication.

4. eCash System

Flash implements a chaumian eCash system offering:

  • Full transaction privacy
  • Off-chain scaling
  • Offline payment capabilities

5. BTCPay Server Integration

Flash leverages BTCPay Server for:

  • Flash Cards payment processing
  • Rewards system management
  • Merchant services infrastructure

System Architecture

Flash’s architecture is designed for reliability, scalability, and security with these key components:

Server Components

  • API Layer, Authentication Service, Lightning Service
  • Bitcoin Service, NOSTR Relay, eCash Mint
  • Database Cluster, Analytics Engine, BTCPay Server

Client Components

  • Secure Key Storage, Local Database, NOSTR Client
  • Backup Systems, Payment Logic

Security Model

Flash employs multiple security layers:

  • HSM-protected nodes for Lightning and Bitcoin keys
  • Multi-signature wallets for cold storage reserves
  • Regular security audits and encrypted databases
  • Rate limiting and anomaly detection systems

Open Source Components

Flash builds upon and contributes to:

  • LND - Lightning Network implementation
  • Galoy - Bitcoin banking infrastructure
  • NOSTR - Decentralized social protocol
  • Breez SDK - Lightning SDK components
  • Cashu - eCash implementation
  • BTCPay Server - Self-hosted payment processor

Developer Resources

Flash is committed to open-source development and welcomes community contributions.