FinTech / Blockchain

Crypto Payments – Stablecoin Gateway

Data Cell (internal R&D)·6 months

Angular 12TypeScriptWeb3.jsSolidity.NET 5PostgreSQLWebSocket

The Problem

An R&D initiative to explore stablecoin payments for B2B invoicing. Needed to prototype a merchant dashboard handling multi-chain transactions with compliance guardrails.

Constraints

Multi-chain: Ethereum + Polygon + BSC
KYC/AML compliance requirements
R&D budget – prototype quality, not production
Team of 2 developers + 1 blockchain specialist

My Role

Frontend & Research Lead

Architecture

Angular dashboard → .NET Core API → PostgreSQL with blockchain listeners. Web3.js for wallet interactions. Event-driven architecture with WebSocket feeds for transaction status updates.

Key Decisions

USDC/USDT Focus over Multi-Token

Limited support to only USDC and USDT stablecoins.

Reduced complexity significantly. These two stablecoins covered 85%+ of the target market volume, making the prototype viable without handling hundreds of token standards.

Highlights

Built a real-time transaction tracker with block confirmation progress
Created a merchant onboarding flow with KYC document upload
Designed a webhook system for payment notifications to merchant backends

Results

Concept only

Working demo

Prototype Delivery

N/A

< 30s on Polygon

Transaction Speed

3 (ETH, MATIC, BSC)

Chains Supported

Lessons Learned

Blockchain UX requires very different loading/error patterns than traditional web apps – users need visibility into transaction states.
Scoping R&D projects tightly (USDC/USDT only) enabled delivery within budget.

What I'd Do Differently

Would use account abstraction for better wallet UX (no MetaMask required).
Would explore Layer 2 rollups for lower fees and faster confirmation.