Is there a way to measure the response time for a request made with Requests?

Yes, you can measure the response time for HTTP requests made with the Python requests library. There are two primary methods: using the built-in Response.elapsed property or manual timing with the time module.

Method 1: Using Response.elapsed (Recommended)

The requests library provides a built-in Response.elapsed property that returns a datetime.timedelta object representing the time from sending the request to receiving the response headers:

import requests

# Send a GET request
response = requests.get('https://httpbin.org/delay/1')

# Get elapsed time as timedelta object
elapsed_time = response.elapsed
print(f"Response time: {elapsed_time}")

# Convert to seconds (float)
elapsed_seconds = elapsed_time.total_seconds()
print(f"Response time: {elapsed_seconds:.3f} seconds")

# Convert to milliseconds
elapsed_ms = elapsed_time.total_seconds() * 1000
print(f"Response time: {elapsed_ms:.0f} ms")

Method 2: Manual Timing with time Module

For more control over what's being measured, use manual timing:

import requests
import time

# Record start time
start_time = time.time()

# Make the request
response = requests.get('https://httpbin.org/delay/1')

# Record end time
end_time = time.time()

# Calculate elapsed time
elapsed_time = end_time - start_time
print(f"Total time: {elapsed_time:.3f} seconds")
print(f"Built-in elapsed: {response.elapsed.total_seconds():.3f} seconds")

Measuring Multiple Requests

Here's how to measure response times for multiple requests and calculate statistics:

import requests
import statistics
from typing import List

def measure_response_times(url: str, count: int = 5) -> List[float]:
    """Measure response times for multiple requests"""
    times = []

    for i in range(count):
        try:
            response = requests.get(url, timeout=10)
            response_time = response.elapsed.total_seconds()
            times.append(response_time)
            print(f"Request {i+1}: {response_time:.3f}s")
        except requests.exceptions.RequestException as e:
            print(f"Request {i+1} failed: {e}")

    return times

# Test multiple requests
url = "https://httpbin.org/get"
response_times = measure_response_times(url, count=5)

if response_times:
    avg_time = statistics.mean(response_times)
    min_time = min(response_times)
    max_time = max(response_times)

    print(f"\nStatistics:")
    print(f"Average: {avg_time:.3f}s")
    print(f"Minimum: {min_time:.3f}s")
    print(f"Maximum: {max_time:.3f}s")

Advanced Timing with Session Objects

When using requests.Session for multiple requests, you can still measure individual response times:

import requests
import time

# Create a session for connection reuse
session = requests.Session()

urls = [
    'https://httpbin.org/get',
    'https://httpbin.org/status/200',
    'https://httpbin.org/json'
]

for url in urls:
    response = session.get(url)
    print(f"{url}: {response.elapsed.total_seconds():.3f}s")

session.close()

Key Differences Between Methods

| Method | What It Measures | Use Case | |--------|------------------|----------| | response.elapsed | Time from request start to response headers received | Server processing time, network latency | | Manual timing | Complete operation including content download | Total end-to-end performance |

Important Notes

• response.elapsed measures time until response headers are received, not until the entire response body is downloaded
• For large file downloads, manual timing will show significantly longer times than response.elapsed
• Both methods exclude DNS resolution time if using connection pooling
• Always handle exceptions when measuring response times in production code
• Consider using timeout parameters to prevent hanging requests

Performance Monitoring Example

Here's a practical example for monitoring API performance:

import requests
import time
from datetime import datetime

def monitor_api_performance(url: str, threshold: float = 1.0):
    """Monitor API response time and alert if threshold exceeded"""
    try:
        start_time = time.time()
        response = requests.get(url, timeout=5)
        total_time = time.time() - start_time
        server_time = response.elapsed.total_seconds()

        print(f"[{datetime.now()}] {url}")
        print(f"  Server response: {server_time:.3f}s")
        print(f"  Total time: {total_time:.3f}s") 
        print(f"  Status: {response.status_code}")

        if server_time > threshold:
            print(f"  ⚠️  WARNING: Response time exceeds {threshold}s threshold")

    except requests.exceptions.Timeout:
        print(f"  ❌ REQUEST TIMEOUT")
    except requests.exceptions.RequestException as e:
        print(f"  ❌ REQUEST FAILED: {e}")

# Monitor an API endpoint
monitor_api_performance("https://httpbin.org/delay/0.5")

This approach provides comprehensive response time measurement capabilities for any HTTP requests made with the requests library.