DEV3 Free Website Speed and SEO Audit Checker — Source Code (Next.js + MongoDB)

Source code of the DEV3 Website Speed and SEO Audit Checker, a Next.js API route and UI that fetch a public page through an SSRF-safe client and score speed, size, titles, headings, canonical, robots, sitemap and security headers.

Free download: sign in to any DEV3 account and click Download ZIP. Try it live: https://dev3.tech/tools/website-audit-checker shows the finished tool running.

What is in the download

• Route handlers and pages for the Next.js App Router
• The service layer, Mongoose models and the UI components, in a dev3-tools/ folder that cannot clash with your own files
• README.md (install, environment, customise), .env.example and an MIT LICENSE

What the code does

• SSRF guard: URL parsing, DNS pinning, private-range blocking, redirect and size limits
• Pure HTML scanner and check engine with scores and fixes
• MongoDB cache for repeat URLs
• Per-IP rate limit and concurrency gate

Tech stack

Next.js 15 (App Router), React 19, TypeScript, Mongoose on MongoDB, Tailwind CSS 4.

Install and customise

The How to install and How to use tabs list the steps. In short: copy the module into a Next.js app, install the listed packages, add the MongoDB connection string and run it.

Good to know

• This is server code: you need a MongoDB database and your own hosting.
• It audits one page per request and does not run a real browser, so it cannot measure rendered performance.