DEV3 Free Keyword Density and SEO Analyzer — Source Code (Next.js + MongoDB)

Source code of the DEV3 Keyword Density and SEO Analyzer, an SEO text analyzer that reports 1 to 3 word phrase density, target keyword placement, title and meta checks and a readability summary, with an optional server-side page fetch.

Free download: sign in to any DEV3 account and click Download ZIP. Try it live: https://dev3.tech/tools/keyword-density-seo-analyzer 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

• N-gram phrase density with stop-word handling and stuffing warnings
• Target keyword count, density and placement in title, description, H1 and first 100 words
• HTML text extraction that skips navigation, footer and forms
• SSRF-guarded URL fetch endpoint with a size cap and rate limit

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.
• Reads the HTML the server returns; pages rendered only by JavaScript show little text.