BlockWatch: Real-Time Blockchain Transaction Monitor
Enterprise-grade blockchain scanning service with instant notifications via Telegram and Discord for Ethereum network monitoring
The Challenge
A fintech startup specializing in cryptocurrency operations needed a robust solution to monitor blockchain transactions in real-time. Their team was manually tracking wallet activities and smart contract events, which led to delayed responses and missed critical transactions worth millions of dollars.
The challenges were multifaceted:
- Monitor thousands of Ethereum addresses simultaneously without delays
- Detect complex smart contract events and decode transaction data
- Provide instant notifications through multiple communication channels
- Handle high transaction volumes during network congestion
- Ensure zero downtime for mission-critical monitoring
- Create an intuitive interface for non-technical team members
Our Solution
We developed BlockWatch - a comprehensive blockchain monitoring platform that combines real-time scanning, intelligent alerting, and seamless integrations with team communication tools.
Architecture & Design
The system architecture was built on several key principles:
Real-Time Event Processing: We implemented a WebSocket-based connection to Ethereum nodes using Infura and Alchemy as redundant providers. The system processes block confirmations in real-time, with sub-second latency for new transactions.
Smart Detection Engine: Our custom transaction decoder analyzes both standard transfers and complex smart contract interactions. The engine recognizes ERC-20, ERC-721, and ERC-1155 token transfers, DeFi protocol interactions, and custom event signatures.
Multi-Channel Notifications: Integration with Telegram Bot API and Discord webhooks ensures teams receive instant alerts in their preferred communication platform. Notifications include formatted transaction details, USD values, gas fees, and direct links to block explorers.
Technical Stack
We selected technologies optimized for high-throughput real-time processing:
- Backend: Node.js with TypeScript for type safety, event-driven architecture using Bull for job queuing
- Blockchain Integration: Web3.js and Ethers.js libraries, WebSocket connections to multiple node providers
- Database: PostgreSQL for transaction history and alerts, Redis for caching and real-time data
- Messaging: Telegram Bot API, Discord.js for bot integration, custom webhook handlers
- Monitoring: Grafana dashboards, Prometheus metrics, PagerDuty for system alerts
- Infrastructure: Docker containers on AWS ECS, auto-scaling based on network load
Key Features
Flexible Watch Rules: Users can create sophisticated monitoring rules based on wallet addresses, contract addresses, token types, transaction values, gas prices, and custom event signatures. Each rule supports complex logic with AND/OR conditions.
Smart Filtering: The system intelligently filters out spam tokens and scam contracts while highlighting high-value or suspicious transactions. Machine learning models identify unusual patterns that might indicate security threats.
Historical Analysis: Complete transaction history with advanced search and filtering capabilities. Users can analyze wallet behavior patterns, track fund flows, and generate compliance reports.
Real-Time Dashboard: A responsive web interface displays live transaction feeds, network statistics, gas price trends, and alert history. The dashboard updates automatically using WebSocket connections.
Custom Alert Templates: Teams can design notification templates with dynamic fields, including transaction details, wallet balances, token prices from CoinGecko, and custom messages.
API Access: RESTful API and WebSocket endpoints allow integration with existing internal systems, trading bots, and analytics platforms.
Implementation Highlights
Performance Optimization: During mainnet congestion when gas prices spike and transaction volumes surge, our system maintains consistent performance. We implemented adaptive polling rates and intelligent caching strategies that reduced node API calls by 75% while maintaining real-time accuracy.
Reliability Engineering: The platform features automatic failover between multiple node providers. If one provider experiences downtime, the system seamlessly switches to backup nodes within seconds. We maintain 99.98% uptime through geographic redundancy and health monitoring.
Security Measures: All API keys and webhook URLs are encrypted at rest. The system includes rate limiting, IP whitelisting, and two-factor authentication. Audit logs track all configuration changes and alert dispatches.
Overcoming Challenges
Transaction Decoding: Ethereum transactions contain encoded data that requires specialized decoding. We built a comprehensive ABI decoder that automatically fetches and caches contract interfaces from Etherscan, enabling human-readable transaction descriptions.
False Positives: Initial alert volumes were overwhelming due to spam tokens and dust attacks. We developed a reputation system that learns from user feedback, automatically suppressing low-value alerts while ensuring critical transactions always trigger notifications.
Network Reorganizations: Blockchain reorgs can invalidate recent blocks. Our system waits for configurable confirmation depths before finalizing alerts, and automatically sends correction notifications if a transaction is removed from the canonical chain.
Result
The platform has been monitoring over 12,000 Ethereum addresses continuously for 6 months with 99.98% uptime. The client reports detecting critical transactions 95% faster than their previous manual process, saving an estimated $2.3M in potential losses. The team now processes 50,000+ daily notifications across 15 Telegram channels and 8 Discord servers, with an average notification delivery time of 800ms from blockchain confirmation.
