APILoadGenAI: High-Concurrency API Stress Tester

A lightweight, high-performance Java load testing utility designed to simulate concurrent traffic, evaluate API stability and analyze API behavior under load.

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Core Architecture

APILoadGenAI combines load generation, concurrent execution, metrics collection, and AI-driven analysis into a single workflow. Requests are executed through Java 21 virtual threads, performance data is gathered during execution, and the results are analyzed by an LLM to identify API behavior and performance characteristics.

Features

• Virtual Thread Concurrency: Java 21 Virtual Threads drive high request volumes with minimal overhead.

• AI-Generated Chaos Payloads: Each request carries a unique Groq-generated JSON payload, surfacing edge cases static data misses.

• Continuous Integration: GitHub Actions automatically runs the test suite on every push.

• Real-Time Latency Metrics: Tracks P50, P95, and P99 latencies plus success/error counts as the run executes.

• LLM-Powered Post-Run Analysis: LLaMA 3.3 70B breaks down results with concrete recommendations.

• Automated Testing: Core components are covered by JUnit and integration tests.
  Code coverage is measured using JaCoCo.

Sample Output

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Testing

JUnit and integration tests cover the core logic classes:

Class	Coverage
LoadConfig	CLI arg parsing and validation
MetricsCollector	Latency math, percentile calculation, success/error counts
ReportPrinter	Report output formatting
HttpClientWrapper	Integration test against a local in-process HTTP server

mvn test

Target Server

A lightweight Spring Boot API is available for local testing: JavaLabs-io/target-api

git clone https://github.com/JavaLabs-io/target-api.git
cd target-api
mvn spring-boot:run
# runs on localhost:8080

Getting Started

Prerequisites

• Java 21+
• Maven 3.9+
• Groq API key

Installation & Execution

git clone https://github.com/SiddhiikaN/APILoadGenAI.git
cd APILoadGenAI

Create .env in the root:

GROQ_API_KEY=your_key_here

mvn package -DskipTests

CLI Args

Flag	Description	Default
--url	Target API endpoint	http://localhost:8080/api/test
--threads	Number of virtual threads	10
--duration	Test duration in seconds	30
--rps	Requests per second	5

java -jar target/APILoadGenAI-1.0-SNAPSHOT-jar-with-dependencies.jar \
  --url http://localhost:8080/api/test \
  --threads 10 \
  --duration 30 \
  --rps 5

CI runs the suite automatically via GitHub Actions on every push.

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_{Siddhika Nagarkar}