 
        
Pick a set of tools based on your target audience:
Basic Free Tools (easy to make):
Meta tag generator
Keyword density checker
Word counter
XML sitemap generator
Robots.txt generator
Advanced Tools (need APIs / scraping):
SERP position tracker
Backlink checker
Domain authority checker
Competitor analysis
Keyword suggestion
💡 Tip: Start with 3–5 tools, then expand later.
Since you already use PHP for CMS (I remember from before 😉), here’s a solid stack:
Frontend: HTML, CSS (modern, minimalist), JS
Backend: PHP (Laravel or plain PHP)
Database: MySQL (if storing results or user data)
Optional: Node.js for faster scraping tasks
Many SEO tasks need data from search engines or other services:
Free APIs:
Google PageSpeed Insights API (site speed)
OpenAI API (for meta descriptions / content ideas)
Paid APIs (more advanced):
Ahrefs API
SEMrush API
SerpApi (for Google SERP scraping)
Moz API
PHP Libraries:
simple_html_dom (scraping)
GuzzleHTTP (API requests)
Example: Keyword Density Checker in PHP:
Accept user input (URL or text)
Fetch and clean the text
Count word frequency
Display results in a neat table
Example code snippet:
php
$text = strtolower(strip_tags($_POST['content'])); $words = str_word_count($text, 1); $frequency = array_count_values($words); arsort($frequency); foreach($frequency as $word => $count) { echo "$word: $count<br>"; } 
Since you want modern + minimalist:
Use CSS Grid / Flexbox
Mobile-first design
Example CSS frameworks:
Tailwind CSS (clean + fast)
Bootstrap (easy but heavier)
Yes… your SEO site needs SEO too:
Create separate pages for each tool
Add proper meta titles/descriptions
Use schema markup (SoftwareApplication)
Speed optimization (CDN, caching)
Once it gets traffic:
Google AdSense
Affiliate programs (e.g., hosting, SEO tools)
Paid premium tools / subscriptions
Selling API credits
Use a VPS or shared hosting
Secure your scripts (avoid abuse via rate-limiting & captcha)
Enable HTTPS
Submit your site to Google Search Console
If you want, I can design you a ready PHP + CSS template for an SEO tools site with 3–5 starter tools so you can just upload and run it.
It’ll already be responsive, minimalist, and expandable.