cloudflare-error-page README

The project's README from github.com/donlon/cloudflare-error-page. As one markdown file: README.md.

Cloudflare Error Page Generator

What does this project do?

This project creates customized error pages that mimic the well-known Cloudflare error page. You can also embed it into your own website.

Online Editor

Here's an online editor to create customized error pages and example server apps. Try it out here.

Editor

Quickstart for Programmers

JavaScript/NodeJS

Install the cloudflare-error-page package using npm:

npm install cloudflare-error-page

The following example demonstrates an Express application that automatically handles server errors.

import express from 'express';
import { render as render_cf_error_page } from 'cloudflare-error-page';

const app = express();

app.get('/', (req, res) => {
  /* Some code that break prod. Pushed by a new employee recently. */
  let [feature_values, _] = features
    .append_with_names(self.config.feature_names)
    .unwrap();
}

app.use((err, req, res) => {
  /* Handle the error intelligently by using a custom handler */
  res.status(500).send(render_cf_error_page({
    "title": "Internal server error",
    "error_code": "500",
    "what_happened": err.toString(),
    "what_can_i_do": "Please try again in a few minutes.",
  }));
});

app.listen(3000);

(Thanks @junduck for creating the original NodeJS version.)

Python

Install cloudflare-error-page using pip.

pip install cloudflare-error-page

Then an error page can be generated using the render function provided by the package. (example.py)

import webbrowser
from cloudflare_error_page import render as render_cf_error_page

# This function renders an error page based on the input parameters
error_page = render_cf_error_page({
    # Browser status is ok
    'browser_status': {
        "status": 'ok',
    },
    # Cloudflare status is error
    'cloudflare_status': {
        "status": 'error',
        "status_text": 'Error',
    },
    # Host status is also ok
    'host_status': {
        "status": 'ok',
        "location": 'example.com',
    },
    # Position of the error indicator, valid options are 'browser', 'cloudflare', and 'host'
    'error_source': 'cloudflare',

    # Texts shown in the bottom of the page
    'what_happened': '<p>There is an internal server error on Cloudflare\'s network.</p>',
    'what_can_i_do': '<p>Please try again in a few minutes.</p>',
})

# Write generated webpage to file
with open('error.html', 'w') as f:
    f.write(error_page)

# Open the generated page in browser
webbrowser.open('error.html')

A demo server using Flask is available in flask_demo.py, and you can also see live demo here.

More Examples

Catastrophic infrastructure failure

params = {
    "title": "Catastrophic infrastructure failure",
    "more_information": {
        "for": "no information",
    },
    "browser_status": {
        "status": "error",
        "status_text": "Out of Memory",
    },
    "cloudflare_status": {
        "status": "error",
        "location": "Everywhere",
        "status_text": "Error",
    },
    "host_status": {
        "status": "error",
        "location": "example.com",
        "status_text": "On Fire",
    },
    "error_source": "cloudflare",
    "what_happened": "<p>There is a catastrophic failure.</p>",
    "what_can_i_do": "<p>Please try again in a few years.</p>",
}

Catastrophic infrastructure failure

Demo

Web server is working

params = {
    "title": "Web server is working",
    "error_code": "200",
    "more_information": {
        "hidden": True,
    },
    "browser_status": {
        "status": "ok",
        "status_text": "Seems Working",
    },
    "cloudflare_status": {
        "status": "ok",
        "status_text": "Often Working",
    },
    "host_status": {
        "status": "ok",
        "location": "example.com",
        "status_text": "Almost Working",
    },
    "error_source": "host",
    "what_happened": "<p>This site is still working. And it looks great.</p>",
    "what_can_i_do": "<p>Visit the site before it crashes someday.</p>",
}

Web server is working

Demo

FAQ

💡 How to show real user IP / Cloudflare Ray ID / data center location in the error page so that it looks more realistic?

Ray ID and user IP field in the error page can be set by ray_id and client_ip properties in the params argument passed to the render function. The real Cloudflare Ray ID and the data center location of current request can be extracted from the Cf-Ray request header (e.g. Cf-Ray: 230b030023ae2822-SJC). Detailed description of this header can be found at Cloudflare documentation.

To lookup the city name of the data center corresponding to the three letter code in the header, you can use a location list here

The demo server runs in our website did handle these. Take a look at this file for reference.

🤔 Is putting this on my website totally legal? As it contains trademarked logo/name and it's pretending to be an official one.

Use it at you own risk. There're still chances Cloudflare send you takedown request or take legal actions. But it depends on if you use it properly. It's better to change texts on the page so users know it's a joke.

If you do want to use an error page that pretends to be a Cloudflare one on your production environment, don't forget to fix your server quickly when it goes down so that they won't find that you are faking their error page. (See #4)

See also

Full Parameter Reference

{
    "html_title": "cloudflare.com | 500: Internal server error",
    "title": "Internal server error",
    "error_code": "500",
    "time": "2025-11-18 12:34:56 UTC",  // Current UTC time will be shown if empty

    // Configuration of "Visit ... for more information"
    "more_information": {
        "hidden": false,
        "text": "cloudflare.com", 
        "link": "https://www.cloudflare.com/",
        "for": "more information",
    },

    // Configuration of the Browser/Cloudflare/Host status block
    "browser_status": {
        "status": "ok", // "ok" or "error"
        "location": "You",
        "name": "Browser",
        "status_text": "Working",
        "status_text_color": "#9bca3e",
    },
    "cloudflare_status": {
        "status": "error",
        "location": "Cloud",
        "name": "Cloudflare",
        "status_text": "Error",
        "status_text_color": "#bd2426",
    },
    "host_status": {
        "status": "ok",
        "location": "Website",
        "name": "Host",
        "status_text": "Working",
        "status_text_color": "#9bca3e",
    },
    // Position of the error indicator, valid options are 'browser', 'cloudflare', and 'host'
    "error_source": "host",

    "what_happened": "<p>There is an internal server error on Cloudflare's network.</p>",
    "what_can_i_do": "<p>Please try again in a few minutes.</p>",

    "ray_id": '0123456789abcdef',  // Random hex string will be shown if empty
    "client_ip": '1.1.1.1',

    // Configuration of 'Performance & security by ...' in the footer
    "perf_sec_by": {
        "text": "Cloudflare",
        "link": "https://www.cloudflare.com/",
    },
}

cloudflare-error-page (donlon/cloudflare-error-page)

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5.8K ·GitHub
Cloudflare-error-page
What is this?A generator that creates fake Cloudflare error pages you can embed into your own website, for jokes, pranks, or testing purposes.
Is it a web tool, a library, or both?Both: there's an online editor to design pages interactively, plus NodeJS and Python packages to render pages programmatically from your own server code.
How do I generate an error page in my app?Install the 'cloudflare-error-page' package via npm or pip, then call its render function (e.g. from the provided example.py or an Express/Flask demo) to produce the HTML.
Do I need Node.js or Python specifically?Either works — the project ships separate packages for NodeJS/npm and Python/pip, with example integrations for Express and Flask.
Is it actually legal to put this on my live site?It's a legal gray area since it uses Cloudflare's trademarked logo and name while impersonating an official error page; the README warns you use it at your own risk and Cloudflare could send a takedown or legal action.
Who would actually use this?Developers who want a joke/prank error page, or anyone testing how a fake 'blocked by Cloudflare' screen looks, since the README even jokes about disguising real downtime as a prank.
Where does this run — client or server side?It runs server-side: you render the HTML with the npm or pip package and serve it, there's no browser extension or app involved.
Can I show the real Cloudflare Ray ID or visitor IP on the fake page?Yes, you can set the rayid and clientip parameters using values extracted from the real Cf-Ray request header, and there's a location list to map the three-letter data center code to a city name.
What happens if I reload the error page demo site?The listed cloudflare-error-page-3th.pages.dev demo shows an error page for every HTTP status code and displays a random one each time you reload.
Is there a React version of this project?Yes, the README links to oftx/cloudflare-error-page, a React reimplementation that can be deployed directly to Cloudflare Pages.
What are similar projects?readme-md-generator, habitica, jsdoc, reclip, razzle, ontology-driven-dev, mkdocs, andhbhakt
Which topics is it in?generator, pip, flask, express, cloudflare, cli-tool, html, web-app, productivity, npm, tool, nodejs
Creator
donlon
Size
1.6 MB
Stars
5.8K
Updated
CommitJul 06
Age
10mo
Commits · 90 Days