HAPROVEN DEVELOPER TOOLKIT

Build, test and refine your code.

Free browser-based tools for HTML, CSS, JavaScript, JSON and PHP. Format snippets, validate data and experiment in one clean workspace.

Open Code Playground Explore All Tools

HTML CSS JavaScript JSON PHP

WORKSPACE

Online Code Playground

Edit code in separate tabs. Run HTML, CSS and JavaScript in the preview; use JSON and PHP for editing and utility workflows.

                                Live Editor
                                HTML workspace
                            

<section class="demo-card">
  <p class="demo-label">HAPROVEN PLAYGROUND</p>
  <h1>Hello, Haproven!</h1>
  <p>Edit HTML, CSS and JavaScript, then run the preview.</p>
  <button id="demo-button">Click me</button>
  <p id="demo-message" aria-live="polite"></p>
</section>

body {
  font-family: system-ui, sans-serif;
  padding: 24px;
  color: #17191f;
  background: #f6f8fc;
}
.demo-card {
  max-width: 560px;
  margin: 20px auto;
  padding: 28px;
  border: 1px solid #e5e7eb;
  border-radius: 18px;
  background: white;
}
.demo-label {
  color: #315efb;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
}
h1 { letter-spacing: -.04em; }
button {
  padding: 10px 16px;
  border: 0;
  border-radius: 9px;
  background: #315efb;
  color: white;
  cursor: pointer;
}

document.getElementById("demo-button")
  ?.addEventListener("click", () => {
    document.getElementById("demo-message").textContent =
      "Your code is working!";
  });

{
  "name": "Haproven",
  "tool": "Code Playground",
  "languages": ["HTML", "CSS", "JavaScript", "JSON", "PHP"],
  "active": true
}

<?php
$name = "Haproven";
echo "Hello, " . htmlspecialchars($name, ENT_QUOTES, "UTF-8") . "!";
?>

HTML · Ready 0 characters

Live Preview HTML + CSS + JavaScript

Preview runs in a sandbox. JSON is data, and PHP requires a PHP server to execute.

</>

One developer workspace

Use the playground for frontend experiments and open the utilities below for formatting, validation and conversion.

01
Frontend preview HTML, CSS and JavaScript
02
Structured data Format, validate and minify JSON
03
PHP helpers Basic formatting and text escaping

◎

Browser-first privacy

These utilities process input locally in your browser. Avoid pasting passwords, API keys, tokens or confidential code.

↗

More from Haproven

Discover more developer resources and projects from the Haproven ecosystem.

Browse all tools →

TOOL DIRECTORY

Developer utilities

Find a tool by language or task. Each utility opens in a focused workspace.

12 tools Runs in your browser

</> HTML

HTML Formatter

Make HTML snippets easier to read with basic indentation.

H− HTML

HTML Minifier

Reduce whitespace between HTML tags for compact snippets.

< Convert

HTML Escape / Unescape

Encode special characters as HTML entities or decode them.

JS JavaScript

JavaScript Formatter

Apply basic formatting to short JavaScript snippets.

JS− JavaScript

JavaScript Whitespace Reducer

Reduce selected whitespace. Review output before using it.

{ } JSON

JSON Formatter

Pretty-print valid JSON with readable indentation.

✓ JSON

JSON Validator

Check JSON syntax and report parser errors.

{…} JSON

JSON Minifier

Convert valid JSON into compact output.

PHP PHP

PHP Basic Formatter

Apply simple indentation to PHP code. Not a full parser.

✓ PHP

PHP Basic Checks

Run lightweight checks; use PHP CLI for real syntax validation.

<?= PHP

HTML Entity Escaper

Escape HTML-sensitive characters before displaying text.

64 Convert

Base64 Converter

Encode or decode UTF-8 text using Base64.

MADE FOR BUILDERS

Useful tools for everyday development

Quick workflows for common tasks without installing a desktop application.

01 / PREVIEW

Experiment quickly

Combine HTML, CSS and JavaScript in the sandboxed preview to test small ideas.

02 / DATA

Keep JSON readable

Format, validate or compact JSON when working with API responses and configuration files.

03 / PHP

Prepare snippets

Use lightweight PHP helpers, then validate and execute PHP with a real PHP runtime.

HELP CENTRE

Frequently asked questions

What to know before using the developer toolkit.

Can I run PHP in this playground?

No. The preview iframe runs HTML, CSS and JavaScript only. PHP must be processed by a server or a PHP runtime before its output can be viewed.

Does the JSON validator check syntax?

Yes. It uses the browser's JSON parser to check syntax and show parsing errors. JSON is data, so it does not run like JavaScript.

Are these formatters compiler-grade?

No. The HTML, JavaScript and PHP formatters are lightweight helpers for snippets. Review the result and use language-specific tooling for production code.

Is my code uploaded?

The included tools process text locally in your browser. Do not enter secrets or sensitive data into snippets.