cmkmteam-blip/open-seo-toolkit

Free open-source SEO tools for Next.js: keyword mixer, bulk slug generator, hreflang tag generator and site crawler. Self-host in one click.

TypeScript

2 commits

updated Sep 26, 2026

https://wizardseo.co/?utm_source=github&utm_medium=open-seo-toolkit&utm_campaign=about

See the code

See what people are saying

Newest first

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Source	Message	Score	Date
	I open-sourced the 4 free SEO tools from my SaaS: keyword mixer, slug generator, hreflang generator and a site crawler (Next.js, MIT) (r/SideProject) I run a small programmatic SEO tool, and over time I built a few free utilities for it. People kept using them more than I expected, so I pulled them out into a clean, self-hostable repo. What's in it: \- Keyword mixer: combine up to 4 lists (e.g. services × cities), removes duplicates, export…	0	Sep 26, 2026

README

Free open-source SEO tools for Next.js

Open SEO Toolkit is a free, self-hosted set of SEO tools built with Next.js and Tailwind CSS: a keyword mixer, a bulk slug generator, a hreflang tag generator and a site crawler that finds missing titles, meta descriptions, H1s, image alt text and broken links.

No sign-up, no tracking and no API keys. Deploy your own copy to Vercel in one click.

Live demo: open-seo-toolkit.vercel.app

Open SEO Toolkit home page

Features

Tool	What it does	Runs
Keyword Mixer	Combines up to 4 lists (services × cities × modifiers) into every long-tail keyword, de-duplicated. Copy, CSV or TXT.	In your browser
Bulk Slug Generator	Turns titles into URL slugs. Handles Turkish (`İ ı ğ ş`), German (`ß`), accents, Arabic and Cyrillic. ASCII transliteration or native-script (UTF-8) slugs, `-` or `_`, max length, stop words, unique suffixes.	In your browser
Hreflang Generator	Builds validated hreflang as HTML `<link>` tags, an XML sitemap or an HTTP `Link` header, with `x-default`. Catches common mistakes (`en-UK`, relative URLs, duplicates). The copied output is only the tags.	In your browser
Site Crawler	Crawls a site from your own deployment and reports missing titles, meta descriptions, H1s, multiple H1s, images without `alt`, `noindex`, and broken internal (and optionally external) links with the pages that link to them. Live progress, filters, CSV export.	Next.js API route
AI keyword ideas (optional)	Suggests keyword ideas for a seed term in the Keyword Mixer. Only appears when `GEMINI_API_KEY` is set on your deployment.	Next.js API route

Screenshots

Keyword Mixer	Bulk Slug Generator

Hreflang Generator	Site Crawler

Deploy

One click

Click Deploy with Vercel above. No environment variables are required.

Run locally

git clone https://github.com/cmkmteam-blip/open-seo-toolkit.git
cd open-seo-toolkit
npm install
npm run dev

Open http://localhost:3000.

Configuration (all optional)

Copy .env.example to .env.local and fill in what you need:

Variable	Default	Purpose
`GEMINI_API_KEY`	(empty)	Turns on AI keyword ideas. Without it the feature is hidden and its API route returns 404. Get a key at Google AI Studio.
`GEMINI_MODEL`	`gemini-flash-latest`	Model used for keyword ideas.
`CRAWL_MAX_PAGES`	`100`	Highest page limit a visitor can choose (max 2000).
`CRAWL_MIN_DELAY_MS`	`500`	Minimum delay between crawler requests.
`ALLOW_PRIVATE_HOSTS`	`false`	Set to `true` only locally to crawl `localhost` or LAN sites.

How the crawler behaves

Stays on the start URL's site (www. and bare domain count as the same site).
Requests one page at a time with a politeness delay. If robots.txt sets a longer Crawl-delay, that wins (capped at 10 s).
Respects robots.txt by default. Its user agent includes OpenSEOToolkit, so site owners can target it.
Blocks private, loopback and cloud-metadata addresses (SSRF protection), re-checks every redirect, allows only ports 80/443 and reads at most 3 MB per page.
Stops by itself before the serverless time limit (maxDuration = 300 s) and returns what it found.
Rate-limited to 5 crawls per IP per 10 minutes on each server instance.
alt="" counts as valid (decorative images). Only images with no alt attribute are reported.

Please crawl only sites you own or are allowed to audit.

Development

npm test        # unit tests (Node test runner): mixer, slugs, hreflang, CSV, robots.txt, SSRF guard, crawler
npm run lint    # type check
npm run build   # production build

Project layout:

src/lib/keyword-mixer.ts   combination logic
src/lib/slug.ts            slugify + transliteration tables
src/lib/hreflang.ts        hreflang validation and output
src/lib/csv.ts             RFC 4180 CSV
src/lib/crawler/           safe fetch, robots.txt, HTML analysis, crawl loop, CSV reports
src/app/api/crawl          streaming crawl endpoint (NDJSON)
src/app/api/ai-keywords    optional Gemini endpoint

Made by pSEO Wizard

This toolkit is built and maintained by pSEO Wizard, a programmatic SEO tool that turns keyword lists into unique landing pages and publishes them to WordPress, Webflow, Shopify and more.

We keep the promotion out of your work, in plain sight:

After a result, each tool shows a clearly labelled card that links to pSEO Wizard.
The footer says "Built by pSEO Wizard", and the browser console shows one friendly message.
Nothing is ever added to what you copy or download: hreflang output, slugs, keywords and CSV files contain only your data. The tests check this.

The links live in src/lib/promo.ts and src/components/CtaCard.tsx.

License

MIT

free

hreflang

keyword-research

nextjs

open-source

programmatic-seo

seo

seo-audit

seo-tools

site-crawler

slug-generator

Contributors

cmkmteam-blip

2 commits

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cmkmteam-blip/open-seo-toolkit

Free open-source SEO tools for Next.js: keyword mixer, bulk slug generator, hreflang tag generator and site crawler. Self-host in one click.

TypeScript

2 commits

updated Sep 26, 2026

https://wizardseo.co/?utm_source=github&utm_medium=open-seo-toolkit&utm_campaign=about

See the code

See what people are saying

Newest first

Most points

Source	Message	Score	Date
	I open-sourced the 4 free SEO tools from my SaaS: keyword mixer, slug generator, hreflang generator and a site crawler (Next.js, MIT) (r/SideProject) I run a small programmatic SEO tool, and over time I built a few free utilities for it. People kept using them more than I expected, so I pulled them out into a clean, self-hostable repo. What's in it: \- Keyword mixer: combine up to 4 lists (e.g. services × cities), removes duplicates, export…	0	Sep 26, 2026

README

Free open-source SEO tools for Next.js

No sign-up, no tracking and no API keys. Deploy your own copy to Vercel in one click.

Live demo: open-seo-toolkit.vercel.app

Open SEO Toolkit home page

Features

Tool	What it does	Runs
Keyword Mixer	Combines up to 4 lists (services × cities × modifiers) into every long-tail keyword, de-duplicated. Copy, CSV or TXT.	In your browser
Bulk Slug Generator	Turns titles into URL slugs. Handles Turkish (`İ ı ğ ş`), German (`ß`), accents, Arabic and Cyrillic. ASCII transliteration or native-script (UTF-8) slugs, `-` or `_`, max length, stop words, unique suffixes.	In your browser
Hreflang Generator	Builds validated hreflang as HTML `<link>` tags, an XML sitemap or an HTTP `Link` header, with `x-default`. Catches common mistakes (`en-UK`, relative URLs, duplicates). The copied output is only the tags.	In your browser
Site Crawler	Crawls a site from your own deployment and reports missing titles, meta descriptions, H1s, multiple H1s, images without `alt`, `noindex`, and broken internal (and optionally external) links with the pages that link to them. Live progress, filters, CSV export.	Next.js API route
AI keyword ideas (optional)	Suggests keyword ideas for a seed term in the Keyword Mixer. Only appears when `GEMINI_API_KEY` is set on your deployment.	Next.js API route

Screenshots

Keyword Mixer	Bulk Slug Generator

Hreflang Generator	Site Crawler

Deploy

One click

Click Deploy with Vercel above. No environment variables are required.

Run locally

git clone https://github.com/cmkmteam-blip/open-seo-toolkit.git
cd open-seo-toolkit
npm install
npm run dev

Open http://localhost:3000.

Configuration (all optional)

Copy .env.example to .env.local and fill in what you need:

Variable	Default	Purpose
`GEMINI_API_KEY`	(empty)	Turns on AI keyword ideas. Without it the feature is hidden and its API route returns 404. Get a key at Google AI Studio.
`GEMINI_MODEL`	`gemini-flash-latest`	Model used for keyword ideas.
`CRAWL_MAX_PAGES`	`100`	Highest page limit a visitor can choose (max 2000).
`CRAWL_MIN_DELAY_MS`	`500`	Minimum delay between crawler requests.
`ALLOW_PRIVATE_HOSTS`	`false`	Set to `true` only locally to crawl `localhost` or LAN sites.

How the crawler behaves

Stays on the start URL's site (www. and bare domain count as the same site).
Requests one page at a time with a politeness delay. If robots.txt sets a longer Crawl-delay, that wins (capped at 10 s).
Respects robots.txt by default. Its user agent includes OpenSEOToolkit, so site owners can target it.
Blocks private, loopback and cloud-metadata addresses (SSRF protection), re-checks every redirect, allows only ports 80/443 and reads at most 3 MB per page.
Stops by itself before the serverless time limit (maxDuration = 300 s) and returns what it found.
Rate-limited to 5 crawls per IP per 10 minutes on each server instance.
alt="" counts as valid (decorative images). Only images with no alt attribute are reported.

Please crawl only sites you own or are allowed to audit.

Development

npm test        # unit tests (Node test runner): mixer, slugs, hreflang, CSV, robots.txt, SSRF guard, crawler
npm run lint    # type check
npm run build   # production build

Project layout:

src/lib/keyword-mixer.ts   combination logic
src/lib/slug.ts            slugify + transliteration tables
src/lib/hreflang.ts        hreflang validation and output
src/lib/csv.ts             RFC 4180 CSV
src/lib/crawler/           safe fetch, robots.txt, HTML analysis, crawl loop, CSV reports
src/app/api/crawl          streaming crawl endpoint (NDJSON)
src/app/api/ai-keywords    optional Gemini endpoint

Made by pSEO Wizard

This toolkit is built and maintained by pSEO Wizard, a programmatic SEO tool that turns keyword lists into unique landing pages and publishes them to WordPress, Webflow, Shopify and more.

We keep the promotion out of your work, in plain sight:

After a result, each tool shows a clearly labelled card that links to pSEO Wizard.
The footer says "Built by pSEO Wizard", and the browser console shows one friendly message.
Nothing is ever added to what you copy or download: hreflang output, slugs, keywords and CSV files contain only your data. The tests check this.

The links live in src/lib/promo.ts and src/components/CtaCard.tsx.

License

MIT

free

hreflang

keyword-research

nextjs

open-source

programmatic-seo

seo

seo-audit

seo-tools

site-crawler

slug-generator

Similar repos

every-app/open-seo

Open source alternative to Semrush and Ahrefs

21,277

seoskillsai/seo-skills-ai

SEO Skills AI: Universal AI SEO Agent & Technical Optimization Suite across Claude Code,…

AgriciDaniel/codex-seo

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AgriciDaniel/claude-seo

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17,741

angelotc/antigravity-seo

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officialrajdeepsingh/awesome-nextjs

A curated list of awesome Nextjs-based libraries that help build small and large-scale applications…

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130

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Contributors

cmkmteam-blip

2 commits

Languages

TypeScript

98.3%

CSS

1.7%