hey - HTTP Load Testing Tool Guide

Table of Contents

• Overview
• Installation
• Basic Usage
• Load Testing Patterns
• Output Analysis
• Advanced Options
• Best Practices
• Common Scenarios

Overview

hey is a modern HTTP load testing tool designed to be simple yet powerful, capable of generating load for benchmarking and functional testing.

Key Features

• Simple command-line interface
• Multiple request methods
• Custom headers
• Request body support
• Concurrent connections
• Detailed statistics
• Response validation
• Proxy support

Installation

Using Go

# Install using go
go install github.com/rakyll/hey@latest

Binary Installation

# Download binary
curl -L https://hey-release.s3.us-east-2.amazonaws.com/hey_linux_amd64 -o hey
chmod +x hey
sudo mv hey /usr/local/bin/

Basic Usage

Simple Tests

# Basic GET request
hey http://localhost:8080/
 
# Specify number of requests
hey -n 1000 http://localhost:8080/
 
# Set number of concurrent workers
hey -c 100 http://localhost:8080/
 
# Combined options
hey -n 1000 -c 100 http://localhost:8080/

Request Methods

# POST request
hey -m POST http://localhost:8080/api
 
# PUT request
hey -m PUT http://localhost:8080/api
 
# DELETE request
hey -m DELETE http://localhost:8080/api

Load Testing Patterns

Basic Load Testing

# Quick load test
hey -n 2000 -c 50 http://localhost:8080/
 
# Sustained load
hey -n 10000 -c 100 http://localhost:8080/
 
# Time-based test
hey -z 30s http://localhost:8080/

Advanced Patterns

# With request body
hey -m POST \
    -d '{"key":"value"}' \
    http://localhost:8080/api
 
# With headers
hey -H "Authorization: Bearer token" \
    -H "Content-Type: application/json" \
    http://localhost:8080/api

Output Analysis

Understanding Output

Summary:
  Total:        30.0665 secs
  Slowest:      1.5234 secs
  Fastest:      0.0234 secs
  Average:      0.2988 secs
  Requests/sec: 334.4324
 
Response time histogram:
  0.023 [1]     |
  0.173 [2]     |∎
  0.323 [85]    |∎∎∎∎∎∎∎∎∎∎∎∎
  0.473 [7]     |∎
  0.623 [2]     |∎
  0.773 [1]     |
  0.923 [1]     |
  1.073 [0]     |
  1.223 [0]     |
  1.373 [0]     |
  1.523 [1]     |

Output Options

# Disable progress output
hey -q http://localhost:8080/
 
# Detailed output
hey -v http://localhost:8080/
 
# Save output to file
hey -o report.csv http://localhost:8080/

Advanced Options

Request Configuration

# Custom headers
hey -H "User-Agent: custom-agent" \
    -H "Accept: application/json" \
    http://localhost:8080/
 
# Basic auth
hey -a username:password http://localhost:8080/
 
# Proxy settings
hey -x http://proxy:8080 http://localhost:8080/

Response Validation

# Disable redirect following
hey -disable-redirects http://localhost:8080/
 
# Set timeout
hey -t 20s http://localhost:8080/
 
# Accept invalid certs
hey -disable-compression http://localhost:8080/

Rate Limiting

# Requests per second
hey -q 100 http://localhost:8080/
 
# Burst size
hey -q 100 -burst 20 http://localhost:8080/

Best Practices

Testing Guidelines

# Warm-up run
hey -n 100 -c 10 http://localhost:8080/
 
# Progressive load
for c in 10 50 100 200; do
    hey -n 1000 -c $c http://localhost:8080/
    sleep 5
done

Resource Monitoring

# Monitor while testing
while true; do
    date
    ps aux | grep hey
    netstat -an | grep ESTABLISHED | wc -l
    sleep 1
done

Quick Reference

Essential Commands

# Basic test
hey http://localhost:8080/
 
# Load test
hey -n 1000 -c 100 http://localhost:8080/
 
# Timed test
hey -z 30s http://localhost:8080/
 
# POST request
hey -m POST -d '{"key":"value"}' http://localhost:8080/

Common Options

-n    # Number of requests
-c    # Number of workers
-z    # Duration of test
-q    # Requests per second
-m    # HTTP method
-H    # Headers
-d    # Request body
-o    # Output file

Example Scripts

Basic Load Test

#!/bin/bash
# Progressive load testing
URL="http://localhost:8080/"
REQUESTS=1000
 
for workers in 10 50 100; do
    echo "Testing with $workers workers"
    hey -n $REQUESTS -c $workers "$URL"
    sleep 5
done

API Testing

#!/bin/bash
# API endpoint testing
URL="http://localhost:8080/api"
TOKEN="your-auth-token"
 
hey -n 1000 -c 50 \
    -m POST \
    -H "Authorization: Bearer $TOKEN" \
    -H "Content-Type: application/json" \
    -d '{"test": "data"}' \
    "$URL"

Comprehensive Test Suite

#!/bin/bash
# Full test suite
BASE_URL="http://localhost:8080"
ENDPOINTS=(
    "/"
    "/api/v1"
    "/api/v2"
)
 
for endpoint in "${ENDPOINTS[@]}"; do
    echo "Testing $endpoint"
    hey -n 500 -c 50 "${BASE_URL}${endpoint}"
    sleep 2
done

Performance Monitoring

#!/bin/bash
# Monitor and log performance
URL="http://localhost:8080/"
OUTPUT_DIR="hey_results"
 
mkdir -p "$OUTPUT_DIR"
 
run_test() {
    local workers=$1
    local timestamp=$(date +%Y%m%d_%H%M%S)
    local output_file="${OUTPUT_DIR}/test_${workers}_${timestamp}.txt"
    
    echo "Running test with $workers workers"
    hey -n 1000 -c "$workers" "$URL" > "$output_file"
}
 
# Run tests with different concurrency levels
for workers in 10 50 100; do
    run_test "$workers"
    sleep 5
done

---

Remember:

• Start with lower loads
• Monitor server resources
• Use appropriate timeouts
• Consider rate limiting
• Document test conditions
• Analyze all metrics

For detailed information, consult the hey documentation (hey -h).