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005 — Demos

Real Systems, Live

21 demos Betfair API · Apache Kafka · Spring Boot · Architecture
Live WeatherNew
Racecourse Weather & Going Conditions

Live weather at every UK horse racing venue — current conditions, 7-day forecast, and an estimated going condition (Firm through Heavy) derived from 72-hour Open-Meteo rainfall data. Click any of the 57 venues on the interactive UK map.

Open-Meteo API · Leaflet.js · OpenStreetMap · WMO Weather Codes · Vanilla JS
Horse Racing Going Conditions Open-Meteo UK Racecourses Weather API
Betfair ToolNew
Betfair BSP File Analyser

Upload a Betfair Starting Price CSV from the Historical Data Portal — analyse race results, BSP vs pre-play WAP drift/steam, and matched volume breakdown by phase. Zero server-side processing.

Betfair BSP Export · SP Drift Analysis · Canvas 2D · FileReader API · Vanilla JS
Betfair API Starting Price BSP Historical Data Market Analysis
Betfair ToolNew
Betfair Historical Data Parser

Upload a Betfair historical streaming file — extract price history, matched volume, market timeline, and runner summary to CSV. Parses the Streaming API NDJSON delta format entirely in your browser. No server required.

Betfair Streaming API · NDJSON Delta Format · FileReader API · Canvas 2D · Vanilla JS
Betfair API Streaming API Historical Data Market Analysis NDJSON
Observability
Spring Boot Observability

Watch the three pillars of observability — distributed traces, live Micrometer metrics, and structured MDC logs — update in real time as requests flow through a Spring Boot microservices system. Click Inject Error to trigger a failure cascade.

Spring Boot 3.4 · OpenTelemetry · Micrometer · Logback MDC · Jaeger · Loki
OpenTelemetry Micrometer Prometheus Loki Spring Boot
DevOps
CI/CD Pipeline Visualiser

Watch code flow from Git push through parallel tests, security scanning, Docker build, ECR push, and zero-downtime blue/green ECS deployment — with realistic timings, occasional failures, and auto-retry.

GitHub Actions · Maven · Testcontainers · Trivy · AWS CDK
GitHub Actions Docker AWS ECR ECS Testcontainers
Interactive
Event-Driven Architecture Visualiser

Animated canvas diagram of a production Apache Kafka microservices system — watch market data fan out through Spring Boot services, trigger trading signals, and complete the order lifecycle in real time.

Apache Kafka 3.7 · Spring Boot 3.4 · Java 21 · AWS ECS
Apache Kafka Spring Boot Architecture Java 21
AWS Cloud
AWS Serverless Architecture

Animated diagram of a production AWS serverless stack — watch API requests flow through CloudFront, API Gateway, Lambda Authorizer, Lambda Handler, SQS, DynamoDB, S3 and CloudWatch. Click any service to inspect it.

API Gateway · Lambda Java 21 · SQS · DynamoDB · S3 · CDK
AWS Lambda API Gateway DynamoDB SQS CDK
Backtest
Trading Strategy Backtest

Watch a WoM-driven trading strategy run on a real Betfair race — signals fire when back money dominates, orders place at the live price, and P&L resolves at the result. Adjust threshold and stake in real time.

Betfair Streaming API · WoM Signal · Java · Canvas API
Strategy Weight of Money Backtest Betfair API
Live Data
Betfair Exchange Market Replay

Replay of a real Betfair WIN market — live price ladder, order book depth, Weight of Money indicator, and LTP chart. Built directly on the Betfair Streaming API delta format.

Betfair Streaming API · Java · Canvas API · Vanilla JS
Betfair API Streaming API Java Canvas
Interactive
Betfair Price Ladder Simulator

Interactive Betfair price ladder — watch a live animated order book with back and lay depth, Weight of Money indicator, steam move signals, and a real-time tick rounding tool for all 10 price bands.

Betfair Tick Ladder · Order Book Simulation · WoM Signal · Vanilla JS
Betfair API Price Ladder Order Book Weight of Money
Resilience
Circuit Breaker State Machine

Watch the CLOSED → OPEN → HALF-OPEN state machine animate live — inject failures to trip the breaker, watch it protect the service, then recover through the half-open probe state. Tune thresholds in real time.

Resilience4j · Spring Boot 3.4 · Micrometer · Circuit Breaker Pattern
Resilience4j Spring Boot Architecture Distributed Systems
Tool
Betfair Overround Calculator

Enter prices for any Betfair market — see implied probabilities, overround percentage, market efficiency gauge, fair prices, and commission-adjusted returns. Six presets from 5-runner flat to football 3-way.

Implied Probability · Overround · Normalised Probability · Commission Adjustment
Betfair API Market Efficiency Probability Trading
Java 21
Platform Threads vs Virtual Threads

Drag a concurrency slider from 10 to 2,000 concurrent requests — watch Tomcat's fixed thread pool saturate and start rejecting requests while Java 21 virtual threads scale linearly. Tune pool size and I/O duration live.

Java 21 Virtual Threads · Project Loom · Spring Boot 3.2 · Tomcat
Java 21 Virtual Threads Project Loom Spring Boot Concurrency
Spring Boot
HikariCP Connection Pool Simulator

Tune maxPoolSize, request rate, and query time — watch pool slots cycle idle→active→complete, queue depth build under load, and throughput collapse when the pool exhausts. Surge Load and Drain buttons stress-test your config.

HikariCP · Spring Boot 3.4 · JDBC · Connection Pool Tuning
HikariCP Spring Boot JDBC Connection Pool Performance
Architecture
CQRS Pattern Visualiser

Watch commands flow through the write model — validate, mutate the aggregate, append to the event store — then see domain events fan out via the event bus and bring the read model projections into sync. Fire commands and queries live.

CQRS · Event Sourcing · Spring Boot 3.4 · Axon Framework · PostgreSQL
CQRS Event Sourcing Spring Boot Architecture Domain-Driven Design
Betfair Signal
Betfair Steam Move Detector

Watch Weight of Money and tick velocity combine to fire steam signals across three simulated runners. Adjust WoM threshold and tick-velocity sensitivity, inject a steam event manually, and watch price sparklines shorten on the authentic Betfair tick ladder.

Betfair Tick Ladder · WoM Signal · Tick Velocity · Vanilla JS
Betfair API Weight of Money Steam Move Trading Signal Price Ladder
Betfair Tool
Betfair Hedging Calculator

Enter your back stake, back odds and current lay odds — instantly see the optimal lay stake, lay liability, and guaranteed P&L locked in for both outcomes. Includes Betfair commission and tick ladder validation.

Back/Lay Hedging · Betfair Tick Ladder · Commission Adjustment · Vanilla JS
Betfair API Hedging Trading Dutch Book Lay Betting
Architecture
Rate Limiter Comparison

Compare Token Bucket, Sliding Window, and Fixed Window algorithms side by side with the same request burst. Adjust the limit and burst size, then fire requests to see exactly where each algorithm accepts and where it rejects.

Token Bucket · Sliding Window · Fixed Window · Resilience4j · Spring Boot
Rate Limiting Token Bucket Sliding Window Architecture Java
Architecture
Saga Pattern Visualiser

Watch a distributed saga execute across Order, Inventory, Payment and Notification services. Inject failure at any step to trigger compensating transactions rolling back in reverse — showing how microservices achieve eventual consistency without a global lock.

Saga Pattern · Compensating Transactions · Spring Boot · Apache Kafka · Axon
Saga Pattern Distributed Transactions Spring Boot Architecture Kafka
Apache Kafka
Kafka Consumer Group Rebalancing

Watch partition assignment animate as consumers join and leave a group. Add consumers, remove them gracefully, or kill them to simulate a session timeout — and observe how the group coordinator redistributes all 6 partitions.

Apache Kafka · Spring Kafka · Consumer Group Protocol · Java
Apache Kafka Spring Kafka Consumer Group Rebalancing Java
Betfair Signal
Betfair Market Depth Heatmap

Watch order book volume across Betfair tick prices evolve in real time. Liquidity concentrates in a tight band around the LTP, builds as the race approaches the off, and collapses in the final seconds. Inject a steam move to watch depth evaporate.

Betfair Streaming API · Order Book Depth · Canvas API · Vanilla JS
Betfair API Order Book Market Depth Heatmap Streaming API