HTTP 404 Not Found Status Code - Test & Mock API

Code Examples

Here are examples of how to test HTTP 404 responses in different programming languages:

Select options below to see how to use advanced features in your code:

Add Custom Delay (x-delay) - Test timeout scenarios (1-60000ms)

Add Custom Headers (x-response) - Add custom HTTP headers to response

Add Custom Payload (x-payload) - Control entire response body with JSON

Request:

curl https://free.mockerapi.com/404

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

fetch('https://free.mockerapi.com/404')
  .then(response => {
    console.log('Status:', response.status); // 404
    return response.json();
  })
  .then(data => {
    console.log('Response:', data);
  })
  .catch(error => {
    console.error('Error:', error);
  });

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

import requests

response = requests.get('https://free.mockerapi.com/404')

print(f'Status Code: {response.status_code}')  # 404
print(f'Response: {response.json()}')

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

require 'net/http'
require 'json'

uri = URI('https://free.mockerapi.com/404')
response = Net::HTTP.get_response(uri)

puts "Status Code: #{response.code}"  # 404
puts "Response: #{JSON.parse(response.body)}"

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

package main

import (
    "fmt"
    "io"
    "net/http"
)

func main() {
    resp, err := http.Get("https://free.mockerapi.com/404")
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    fmt.Printf("Status Code: %d\n", resp.StatusCode)  // 404

    body, err := io.ReadAll(resp.Body)
    if err != nil {
        panic(err)
    }

    fmt.Printf("Response: %s\n", body)
}

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

import java.net.http.*;
import java.net.URI;

public class HttpStatusTest {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://free.mockerapi.com/404"))
            .GET()
            .build();

        HttpResponse response = client.send(request,
            HttpResponse.BodyHandlers.ofString());

        System.out.println("Status Code: " + response.statusCode());  // 404
        System.out.println("Response: " + response.body());
    }
}

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

Request:

const https = require('https');

https.get('https://free.mockerapi.com/404', (res) => {
  console.log('Status Code:', res.statusCode);  // 404

  let data = '';

  res.on('data', (chunk) => {
    data += chunk;
  });

  res.on('end', () => {
    console.log('Response:', JSON.parse(data));
  });
}).on('error', (err) => {
  console.error('Error:', err.message);
});

Response Headers:

HTTP/1.1 404 Not Found
Content-Type: application/json
Access-Control-Allow-Origin: *

Response Body:

{
  "success": false,
  "status": 404,
  "statusText": "Not Found - The server cannot find the requested resource",
  "timestamp": "2025-10-08T10:30:45.123Z",
  "request": {
    "method": "GET",
    "url": "/404",
    "fullUrl": "https://free.mockerapi.com/404"
  }
}

What is HTTP 404 Not Found?

HTTP 404 Not Found indicates that the server cannot or will not process the request due to something that is perceived to be a client error. This could be malformed request syntax, invalid request message framing, or deceptive request routing.

The client should not repeat the request without modifications.

When Does This Happen?

A 404 Not Found response is returned when:

The request has invalid syntax or malformed request parameters
Required parameters are missing from the request
The request body contains invalid JSON or XML
Query parameters have invalid values or formats
The request URL is malformed or contains invalid characters
Request headers contain invalid or conflicting values

Try It Live

Click the button below to make a live request and see the 404 Not Found response

Common Use Cases

🔍 Input Validation Testing

Test how your application handles invalid input data and displays appropriate error messages to users.

🛡️ Error Handling

Ensure your application properly catches and handles bad request errors without crashing.

📝 Form Validation

Test form validation logic and ensure users receive clear feedback about invalid submissions.

🔄 API Testing

Verify that your API correctly validates request parameters and returns appropriate error responses.

Not Found

Code Examples

What is HTTP 404 Not Found?

When Does This Happen?

Try It Live

Common Use Cases

🔍 Input Validation Testing

🛡️ Error Handling

📝 Form Validation

🔄 API Testing

🎨 UI/UX Development

📚 Documentation

Related Client Error Status Codes