DEV Community

Scrapfly
Scrapfly

Posted on • Originally published at scrapfly.io on

What is Status Code 403 Forbidden and How to Fix it

#http

What is Status Code 403 Forbidden and How to Fix it

The infamous 403 Forbidden status code is a response that's often encountered by web and automation developers. It's a frustrating error that can be caused by a plethora of reasons which is exactly what we'll cover in this article.

We'll take a look at what is the 403 Error, how can we replicate it and what causes it. We'll also cover the most common errors and popular solution that can fix your HTTP requests and prevent the 403 Forbidden status code from ever bothering you again.

What does 403 Forbidden Mean?

This 403 status code is a catch-all error for all requests where the client is authenticated but is not authorized to access the requested resource. This can be due to a variety of reasons such as:

  • If authenticated, the client lacks the necessary granual permissions to access the resource. Like resource belonging to a different user or a user group
  • Client's IP address is blocked by the server
  • Client's IP address geolocation is blocked by the server
  • Client is being rate limited or rejected for too many connections or undesirability (i.e. being a robot)

So what causes 403 forbidden error can be unclear but depend on the use context we can figure out the exact reason with a few easy steps and even prevent it from happening.

Checking for Error Details

One way to figure out exactly what caused the 403 Forbidden error is to check the response headers and body. The server might provide additional information in the response body that can help you debug the issue.

For example, the response body might contain a message like "You are not authorized to access this resource" or "Your IP address has been blocked".

Alternatively, the X- prefixed headers can have hints or special IDs that can be used with the service provider to get more information about the cause of the error.

So to summarize:

  • check response body for error messages
  • check X- prefixed headers for clues

Server Implementation

To better understand http status code 403, let's take a look at how it can be implemented in a web server. Here's an example of how you can return a 403 Forbidden response in Python using the Flask web framework:

import time
from flask import Flask, request, abort, jsonify

app = Flask( __name__ )

# Blocked IPs for demonstration

# Middleware to check IP-based blocking
blocked_ips = ["192.168.1.10", "203.0.113.5"]
@app.before_request
def block_ip():
    if request.remote_addr in blocked_ips:
        abort(403, description="Your IP is blocked.")

# Example Route protected by user roles
users = {
    "user1": {"role": "admin"},
    "user2": {"role": "user"},
}
@app.route("/admin")
def admin():
    user = request.args.get("user")
    if not user or users.get(user, {}).get("role") != "admin":
        abort(403, description="Access denied. Admins only.")
    return jsonify({"message": "Welcome, Admin!"})

# Example Route Rate limiting example (limit 5 requests per minute)
request_count = {}
_last_clear = time.time()
@app.route("/rate-limited")
def rate_limited():
    if time.time() - _last_clear > 60:
        request_count.clear()
        _last_clear = time.time()
    user_ip = request.remote_addr
    request_count[user_ip] = request_count.get(user_ip, 0) + 1

    if request_count[user_ip] > 5:
        abort(403, description="Rate limit exceeded. Try again later.")

    return jsonify({"message": "Request successful!"})

# Run the app
if __name__ == " __main__":
    app.run(debug=True)
Enter fullscreen mode Exit fullscreen mode

In this server application we implement 3 common reasons for 403 Forbidden errors:

  • /admin route is protected by user role check and only allows users with ?role=admin to access it.
  • /rate-limited route is rate limited to 5 requests per minute and will return 403 error if the limit is exceeded.
  • block_ip middleware blocks requests from IP addresses in the blocked_ips list to similate IP blacklisting.

In real life, these policies tend to be a bit more complex and dynamic but this example should give you a good idea of how 403 Forbidden errors can be implemented and perspective on how to handle them on the client side.

Next, let's take a look at the most common reasons for the 403 Forbidden error and how you can fix them.

Error 403 Missing Permissions

The most likely reasons for the 403 Forbidden error is missing permissions. This can happen when you're trying to access private resource that requires authentication of a specific user or user group.

Note that if credentials are incorrect a HTTP 401 Unauthorized error is usually returned instead.

To fix this issue, you need to ensure that you have the correct permissions to access the resource. This might involve:

  • Grant the granular permissions to your user through management console if available.
  • Ensure you're accessing the correct resource with the correct user credentials.

That being said, for public resources like public web pages the meaning for HTTP 403 can be different and usually imply rate limiting or blocking. Let's take a look these next.

Error 403 Rate Limiting

Generally rate limiting is indicated by a 429 Too Many Requests error but in some cases a 403 Forbidden error can be returned as well especially in web scraping or web automation tasks where the reasoning can be obscured purposefully.

This can be identified if 403 errors are returned only after a certain number of requests or after a certain time period.

In rate limiting cases, the response might have an indication of what rate limit policy is in place through X- prefixed headers. For example:

import httpx

response = httpx.get("https://api.example.com")
print(response.headers)
{
    "X-RateLimit-Limit": "60",
    "X-RateLimit-Remaining": "0",
    "X-RateLimit-Reset": "1617228400",
}
Enter fullscreen mode Exit fullscreen mode

In this case, the example API provides exact details about the rate limit policy:

  • The X-RateLimit-Limit header tells you how many requests you can make in a given time frame.
  • The X-RateLimit-Remaining header tells you how many requests you have left.
  • The X-RateLimit-Reset header tells you when the rate limit will reset.

As X- headers are non-standard this can vary from service to service.

Additionally, these limits can apply to concurrent connections as well. For example, if you're making too many requests at the same time using multiple threads or async connections the server can reject you with a 403 error with message like "Too many concurrent connections" and usually provide similar X- prefixed headers to give you more information.

To debug 403 rate limiting issues you can implement your own rate limiting logic to find the sweet spot for your request scale.

How to Bypass 403 Rate Limiting

To bypass rate limiting issues there are several strategies you can use depending on what's being rate limited.

Most rate limiting policies are based on IP address so you can try using a proxy service to change your IP address. For example, if rate limit is 10 requests per minute on a single IP address, using a pool of 10 proxies can give you 100 requests per minute.

Here's how proxies can be used in popular HTTP clients

# Python httpx
# -------------------------
import httpx

# Define the proxy URL
proxy = "http://your-proxy-url:port"

# Make a request using the proxy
response = httpx.get('http://httpbin.dev/ip', proxies={"http://": proxy, "https://": proxy})

print(response.text)

// Javascript Fetch
// -----------------------------------
// Define the proxy URL
const proxyUrl = "http://your-proxy-url:port";

// Using fetch with a proxy
fetch('http://httpbin.dev/ip', {
    method: 'GET',
    agent: new HttpsProxyAgent(proxyUrl) // Requires 'https-proxy-agent' package
})
.then(response => response.text())
.then(data => console.log(data))
.catch(error => console.error('Error:', error));

// GO
// ------------------------------------
package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
    "golang.org/x/net/proxy"
)

func main() {
    // Define the proxy URL
    proxyURL, _ := proxy.SOCKS5("tcp", "your-proxy-url:port", nil, proxy.Direct)

    // Create a new HTTP client with the proxy
    httpTransport := &http.Transport{Dial: proxyURL.Dial}
    client := &http.Client{Transport: httpTransport}

    response, err := client.Get("http://httpbin.dev/ip")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer response.Body.Close()

    body, _ := ioutil.ReadAll(response.Body)
    fmt.Println(string(body))
}

# Rust reqwest
# ------------------------------------
use reqwest::Proxy;

#[tokio::main]
async fn main() {
    // Define the proxy URL
    let proxy = Proxy::http("http://your-proxy-url:port").unwrap();

    // Create a client with the proxy
    let client = reqwest::Client::builder()
        .proxy(proxy)
        .build()
        .unwrap();

    let response = client.get("http://httpbin.dev/ip").send().await.unwrap();
    let body = response.text().await.unwrap();

    println!("{}", body);
}

// PHP
// ------------------------------
<?php
// Define the proxy URL
$proxy = 'your-proxy-url:port';
$ch = curl_init('http://httpbin.dev/ip');

// Set cURL options
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PROXY, $proxy);

$response = curl_exec($ch);
curl_close($ch);

echo $response;
?>


# Using cURL with a proxy
# ----------------------------------
curl -x http://your-proxy-url:port http://httpbin.dev/ip
Enter fullscreen mode Exit fullscreen mode

Proxies can be a great way to bypass IP based rate limiting and for more on proxies see our proxy introduction guide

For rate limiting based on other factors like authentication tokens there isn't much we can do other than to follow them or increase the amount of tokens available to us.

There are some other less common rate limiting vectors like session cookies or user agent headers. In these cases, just like with IP address based limiting we can distribute our connections through multiple sessions or user agents to bypass the rate limit.

Here's how User-Agent headers and cookies can be set in popular HTTP clients:

# Python (httpx)
# ---------------------------------------
import httpx

# Define the proxy URL and headers
proxy = "http://your-proxy-url:port"
headers = {"User-Agent": "YourUserAgent"}
cookies = {"cookie_name": "cookie_value"}

# Make a request using the proxy with headers and cookies
response = httpx.get(
    'http://httpbin.dev/headers',
    headers=headers,
    cookies=cookies,
    proxies={"http://": proxy, "https://": proxy}
)

print(response.text)


// Javascript Fetch
// --------------------------------------------
// Define the proxy URL and headers
const proxyUrl = "http://your-proxy-url:port";
const headers = {
    "User-Agent": "YourUserAgent",
    "Cookie": "cookie_name=cookie_value"
};

// Using fetch with a proxy, headers, and cookies
fetch('http://httpbin.dev/headers', {
    method: 'GET',
    headers: headers,
    agent: new HttpsProxyAgent(proxyUrl) // Requires 'https-proxy-agent' package
})
.then(response => response.text())
.then(data => console.log(data))
.catch(error => console.error('Error:', error));

// Go
// ---------------------------------------
package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
    "golang.org/x/net/proxy"
)

func main() {
    // Define the proxy URL
    proxyURL, _ := proxy.SOCKS5("tcp", "your-proxy-url:port", nil, proxy.Direct)

    // Create a new HTTP client with the proxy
    httpTransport := &http.Transport{Dial: proxyURL.Dial}
    client := &http.Client{Transport: httpTransport}

    // Create a new request with headers and cookies
    req, _ := http.NewRequest("GET", "http://httpbin.dev/headers", nil)
    req.Header.Set("User-Agent", "YourUserAgent")
    req.Header.Set("Cookie", "cookie_name=cookie_value")

    response, err := client.Do(req)
    if err != nil {
        fmt.Println(err)
        return
    }
    defer response.Body.Close()

    body, _ := ioutil.ReadAll(response.Body)
    fmt.Println(string(body))
}

# Rust reqwest
# ----------------------------------
use reqwest::{Client, header};

#[tokio::main]
async fn main() {
    // Define the proxy URL
    let proxy = reqwest::Proxy::http("http://your-proxy-url:port").unwrap();

    // Create a client with the proxy
    let client = Client::builder()
        .proxy(proxy)
        .default_headers({
            let mut headers = header::HeaderMap::new();
            headers.insert(header::USER_AGENT, header::HeaderValue::from_static("YourUserAgent"));
            headers.insert(header::COOKIE, header::HeaderValue::from_static("cookie_name=cookie_value"));
            headers
        })
        .build()
        .unwrap();

    let response = client.get("http://httpbin.dev/headers").send().await.unwrap();
    let body = response.text().await.unwrap();

    println!("{}", body);
}


// PHP
// -----------------------------
<?php
// Define the proxy URL
$proxy = 'your-proxy-url:port';
$ch = curl_init('http://httpbin.dev/headers');

// Set headers and cookies
$headers = [
    'User-Agent: YourUserAgent',
    'Cookie: cookie_name=cookie_value'
];

// Set cURL options
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PROXY, $proxy);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$response = curl_exec($ch);
curl_close($ch);

echo $response;
?>



# Using cURL with a proxy, User-Agent, and cookies
curl -x http://your-proxy-url:port -A "YourUserAgent" --cookie "cookie_name=cookie_value" http://httpbin.dev/headers
Enter fullscreen mode Exit fullscreen mode

For more on User Agent strings see our complete user-agent string instroduction.

As for cookie based sessions, you can usually establish multiple session by connecting to the session entry point (like homepage of a website).

Error 403 Blocking

By far the most common HTTP error 403 reason is simply - blocking. Especially when working with public resources like public web pages. This can be due to a variety of reasons such as:

  • Your IP address is blacklisted
  • The connection is being identified as a bot
  • The server is blocking requests from certain countries
  • The server is blocking requests from certain user agents

For user agents and IP addresses we've already covered how IP addresses can be configured with proxies and user-agent strings can be generated to bypass these blocks.

For HTTP client identification there are several factors that can be used to identify undesired connections which usually differ from web browsers in several key aspects:

  • HTTP client headers are different from browser headers. This includes headers like Accept- and even header ordering.
  • HTTP version used by the browser is usually HTTP2 or HTTP3 while most http clients use HTTP1.1.
  • Various fingerprinting techniques like HTTP fingerprint or TLS fingerprint can be used to identify the client.

How to Bypass 403 Blocking

For all techniques used to identify automated connections see our guide on how bot connections are being identified and how to prevent it. However, a good starting point would be to start with an HTTP client that fortifies your requests against the most common detection methods like:

Bypass 403 with Scrapfly

If your 403 error code is caused by blocking or rate limiting then Scrapfly can resolve this issue for you!

What is Status Code 403 Forbidden and How to Fix it

ScrapFly provides web scraping, screenshot, and extraction APIs for data collection at scale.

FAQ

Before we wrap up this article lets cover some frequently asked questions about the 403 error.

What is the difference between 401 Unauthorized and 403 Forbidden?

The main difference between a 401 Unauthorized and a 403 Forbidden error is that the 401 error means that the client is not authenticated at all to access the resource, while the 403 error indicates that the client is authenticated (or doesn't need to) but is not authorized to access this specific resource.

What is the difference between 403 Forbidden and 429 Too Many Requests?

The 403 Forbidden error means that the client is forbidden from accessing the resource, while the 429 Too Many Requests error means that the client has exceeded the rate limit set by the server. Though, 403 can also be used for rate limiting purposes where the client is obfuscated from the information about rate limiting.

What is the difference between 403 Forbidden and 404 Not Found?

The 403 Forbidden error means that the client is forbidden from accessing the resource, while the 404 Not Found error means that the resource simply doesn't exist. However, in practice 404 and 403 are sometimes used interchangeably to obfuscate the existence of the resource to bots.

Summary

HTTP 403 Forbidden errors are a common issue faced by web developers and automation engineers. The error can be caused by a variety of reasons such as missing permissions, rate limiting, or blocking. By understanding the root cause of the error and implementing the right solution, you can prevent the 403 Forbidden status code from affecting your HTTP requests.

As for bypassing blocking and rate limiting issues various strategies like: using proxies, fortifying http client to mimic browser behavior, and using Scrapfly can help you bypass these issues and continue your web scraping or web automation tasks without interruptions.

Top comments (0)

Read next

codepo8 profile image

httpstat.us is a great service to test your APIs and scripts

Christian Heilmann -

patrick_61cbc6392b72286f6 profile image

Axios vs Fetch: Which is Best for HTTP Requests?

Patrick -

gbubemi_attah_8220489db16 profile image

Simplify Gin Input Validation in Go with ginvalidator

Gbubemi Attah -

philip_zhang_854092d88473 profile image

Decoding Networking Protocols: A Guide to TCP/IP, HTTP, Socket, and WebSocket

Philip -