// Crypto Wallet is a SaaS custodial wallet platform that supports multiple blockchains
Overview:
Crypto Wallet is a SaaS custodial wallet platform that supports multiple blockchains (Ethereum, TON, BSC, Polygon, Tron, Polkadot, etc.). The system is designed with multi-tenant architecture so different businesses can securely manage wallets and transactions independently. It provides core wallet services such as deposits, withdrawals, address management, balance tracking, and notifications, all exposed through secure APIs.
My Role:
Designed and led the backend architecture with Node.js and TypeScript.
Implemented multi-tenant structure to isolate tenant data and enforce secure access.
Built APIs for account creation, deposit tracking, and programmable withdrawals.
Developed the blockchain integration layer with chain adapters to support multiple networks.
Designed and implemented hot/cold wallet strategy with automatic sweeping and signing services.
Integrated notification hooks (deposit confirmed, withdrawal processed, low balance alerts).
Defined API-first design, making the wallet consumable as a SaaS product.
Technologies:
Node.js, TypeScript, Express/NestJS, PostgreSQL (ledger), MongoDB, Redis, Kafka, Docker, Kubernetes, Vault/KMS, REST APIs, i18n
Challenges & Achievements:
Designed a secure, multi-tenant wallet service that supports multiple chains.
Built resilient deposit listeners with configurable confirmations and reorg handling.
Created a withdrawal flow with compliance checks, signing, broadcasting, and settlement.
Designed idempotent APIs with HMAC authentication and scoped API keys for tenants.
Delivered a scalable SaaS product where businesses can integrate wallet services directly into their platforms.