Load testing in Rest API - Step-by-Step Execution

Concept Flow - Load testing

Start Load Test

↓

Send Multiple Requests

↓

Measure Response Times

↓

Check Server Behavior

↓

Analyze Results

↓

Report Performance

Load testing sends many requests to a server to check how it handles traffic and measures response times.

Execution Sample

Rest API

for i in range(5):
    response = send_request()
    print(f"Request {i+1}: {response.status_code}")

This code sends 5 requests to a server and prints each response status code.

Execution Table

Request Number	Action	Response Status	Response Time (ms)	Server Load
1	Send request 1	200	120	Low
2	Send request 2	200	130	Low
3	Send request 3	200	125	Medium
4	Send request 4	200	140	Medium
5	Send request 5	200	150	High
-	All requests sent	-	-	Server stable

💡 All 5 requests completed with status 200; server handled load without errors.

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	After 5	Final
i (request count)	0	1	2	3	4	5	5
response.status_code	-	200	200	200	200	200	200
response_time_ms	-	120	130	125	140	150	150
server_load	Low	Low	Low	Medium	Medium	High	High

Key Moments - 2 Insights

Why does the server load increase even though the response status stays 200?

The server load reflects how busy the server is handling requests, but a status 200 means it successfully processed each request regardless of load, as shown in the execution_table rows 3 to 6.

Why do response times increase with more requests?

As more requests are sent, the server works harder, causing response times to rise, visible in the response_time_ms values increasing from 120 to 150 ms in the variable_tracker.

Visual Quiz - 3 Questions

Look at the execution_table, what is the response time for the 3rd request?

A 140 ms

B 130 ms

C 125 ms

D 150 ms

💡 Hint

Check the 'Response Time (ms)' column for Request Number 3 in the execution_table.

At which request number does the server load first become 'Medium'?

A Request 3

B Request 2

C Request 4

D Request 5

💡 Hint

Look at the 'Server Load' column in the execution_table to find when it changes from 'Low' to 'Medium'.

If the response time for request 5 was 200 ms instead of 150 ms, how would the variable_tracker change?

A The 'response.status_code' would change to 500

B The 'response_time_ms' after 5 would be 200 instead of 150

C The 'server_load' would change to 'Low'

D The variable 'i' would be 6

💡 Hint

Check the 'response_time_ms' row in variable_tracker for the value after 5 requests.

Concept Snapshot

Load testing sends many requests to a server to check performance.
It measures response times and server load.
Status 200 means success even under load.
Response times usually increase as load grows.
Helps find how many users a server can handle.

Full Transcript

Load testing is a way to check how a server behaves when many users send requests at once. The process starts by sending multiple requests, measuring how long each takes, and watching how busy the server becomes. In the example, five requests are sent one after another. Each request gets a status code 200, meaning success. The response times grow from 120 ms to 150 ms, showing the server is working harder. The server load changes from low to high as more requests come in. This helps understand the server's limits and performance under stress.