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Engineering/January 25, 2025

Building Marketcap.guide: Real-time Crypto Data Architecture

Technical breakdown of building a real-time cryptocurrency data platform - data ingestion, processing, caching, and serving millions of price updates.

Data ArchitectureReal-time SystemsCrypto DataPerformanceScalability

Share the technical details of building your crypto data platform - from data sources to serving users.

Project Overview and Requirements

What to write about:

  • What marketcap.guide provides to users
  • Performance and reliability requirements
  • Scale considerations (number of tokens, update frequency, users)
  • Competitive landscape and differentiation
  • Technical constraints and budget considerations

Explain what you built and why it required a sophisticated data architecture.

Data Source Strategy

What to write about:

  • Which APIs and data providers you chose
  • Evaluation criteria for data sources
  • Handling multiple sources and data conflicts
  • API rate limiting and cost management
  • Backup strategies for data source failures
  • Data quality and validation approaches

Discuss how you sourced and validated cryptocurrency market data.

Real-time Data Ingestion Pipeline

What to write about:

  • Architecture for ingesting live price feeds
  • Technologies used (WebSockets, message queues, etc.)
  • Handling different update frequencies across tokens
  • Batching vs real-time processing trade-offs
  • Error handling and retry mechanisms
  • Monitoring data ingestion health

Explain how you built the data ingestion system to handle continuous updates.

// Example of WebSocket data ingestion
const priceSocket = new WebSocket('wss://api.exchange.com/v1/stream');

priceSocket.on('message', (data) => {
    const priceUpdate = JSON.parse(data);
    
    // Validate and process price update
    if (isValidPriceUpdate(priceUpdate)) {
        updateQueue.push({
            symbol: priceUpdate.symbol,
            price: priceUpdate.price,
            timestamp: Date.now(),
            volume: priceUpdate.volume
        });
    }
});

Database Design and Storage Strategy

What to write about:

  • Database technology choices (SQL vs NoSQL, time-series DBs)
  • Schema design for price history and metadata
  • Indexing strategies for fast queries
  • Data retention and archival policies
  • Backup and disaster recovery
  • Scaling database reads and writes

Detail your database architecture and how you optimized for both writes and reads.

Caching and Performance Architecture

What to write about:

  • Multi-layer caching strategy
  • Cache invalidation and consistency challenges
  • CDN usage for global performance
  • In-memory vs distributed caching
  • Cache warming strategies
  • Performance monitoring and optimization

Explain how you achieved fast response times for users worldwide.

API Design and Rate Limiting

What to write about:

  • REST API design principles you followed
  • Rate limiting implementation and strategy
  • Authentication and API key management
  • Response format optimization
  • Error handling and status codes
  • API versioning strategy

Share how you designed the public API for developers and applications.

Frontend Performance and Real-time Updates

What to write about:

  • Technology stack for the frontend
  • Real-time price updates to users
  • Optimizing for mobile performance
  • State management for thousands of tokens
  • Progressive loading and lazy loading
  • SEO considerations for crypto data

Discuss the frontend challenges of displaying real-time financial data.

Monitoring, Alerting, and Observability

What to write about:

  • Key metrics you track (latency, accuracy, uptime)
  • Alerting for data quality issues
  • Performance monitoring across the stack
  • Log aggregation and analysis
  • Error tracking and debugging
  • Business metrics and user analytics

Explain how you monitored the health and performance of your data pipeline.

Scaling Challenges and Solutions

What to write about:

  • Traffic spikes during market volatility
  • Database scaling strategies
  • Auto-scaling infrastructure decisions
  • Cost optimization techniques
  • Performance bottlenecks you discovered
  • Architecture evolution as you grew

Share specific scaling challenges and how you solved them.

Data Quality and Accuracy

What to write about:

  • Detecting and handling bad data
  • Cross-validation between data sources
  • Handling market manipulation and flash crashes
  • Data audit trails and corrections
  • User reporting of data issues
  • Regulatory and compliance considerations

Discuss how you ensured data accuracy and reliability.

Lessons Learned and Architecture Evolution

What to write about:

  • Major architectural decisions you'd change
  • Technologies that worked well vs disappointments
  • Unexpected challenges and solutions
  • Cost vs performance trade-offs
  • What you learned about crypto market data
  • Future improvements and features

Reflect on the technical journey and what you'd do differently.


Include architecture diagrams, performance metrics, and code examples. Share specific numbers around throughput, latency, and scale to make this a practical reference for others building similar systems.