@power-seo/core

Framework-agnostic SEO utilities, types, and engines — the shared foundation of the entire @power-seo ecosystem, usable as a standalone TypeScript library that works anywhere.

@power-seo/core is the foundational library shared by all 17 @power-seo packages. It delivers pixel-accurate meta validators, structured meta and link tag builders, URL normalization, keyword density analysis, text statistics, Open Graph and Twitter Card builders, robots directive generation, title template engines, and a token-bucket rate limiter — all in a single zero-dependency TypeScript package. Think of it as combining next-seo, seo-utils, keyword-density, url-normalize, and text-statistics into one unified, tree-shakeable library that runs in Next.js, Remix, Vite, vanilla Node.js, Cloudflare Workers, and Vercel Edge. All 8 utility modules are fully configurable and independently importable.

Zero runtime dependencies — installs clean with nothing else to pull in.

Why @power-seo/core?

Features

• Meta tag builder — buildMetaTags() generates typed arrays of meta tags from a structured SEOConfig
• Open Graph builder — buildOpenGraphTags() with full support for article, profile, book, video, and music OG types
• Twitter Card builder — buildTwitterTags() for summary, large image, player, and app card types
• Hreflang builder — buildHreflangTags() generates <link rel="alternate"> tags for multi-language pages
• Title template engine — applyTitleTemplate() and createTitleTemplate() with %variable% substitution and separator cleanup
• Pixel-accurate meta validators — validateTitle() and validateMetaDescription() measure real SERP pixel widths using Arial font metrics
• URL utilities — resolveCanonical(), normalizeUrl(), toSlug(), stripTrackingParams(), extractSlug(), and more
• Text statistics engine — getTextStatistics() returns word, sentence, paragraph, syllable, and character counts from HTML
• Keyword density calculator — calculateKeywordDensity() and analyzeKeyphraseOccurrences() for single and multi-word keyphrases
• Robots directive builder — buildRobotsContent() and parseRobotsContent() for structured robots meta directives
• Rate limiting — token bucket implementation with createTokenBucket(), consumeToken(), and getWaitTime()
• SEO constants — exported TITLE_MAX_PIXELS, META_DESCRIPTION_MAX_PIXELS, KEYWORD_DENSITY, READABILITY, OG_IMAGE, AI_CRAWLERS, and SCHEMA_TYPES
• 25+ shared TypeScript types — SEOConfig, MetaTag, LinkTag, OpenGraphConfig, TwitterCardConfig, ContentAnalysisInput, and more
• Framework-agnostic — works in Next.js, Remix, Gatsby, Vite, vanilla Node.js, Edge
• Tree-shakeable — "sideEffects": false with named exports per module; import only what you use

Comparison

Installation

npm install @power-seo/core

yarn add @power-seo/core

pnpm add @power-seo/core

Quick Start

import { buildMetaTags, buildLinkTags, validateTitle, resolveCanonical } from '@power-seo/core';

const tags = buildMetaTags({
  description: 'Master SEO in Next.js with structured data and meta tags.',
  openGraph: {
    type: 'article',
    title: 'Next.js SEO Guide',
    images: [{ url: 'https://example.com/og.jpg', width: 1200, height: 630 }],
  },
  twitter: { cardType: 'summary_large_image', site: '@mysite' },
});

const links = buildLinkTags({
  canonical: resolveCanonical('https://example.com', '/nextjs-seo'),
});

const titleCheck = validateTitle('Next.js SEO Best Practices Guide');
console.log(titleCheck.valid); // true
console.log(titleCheck.pixelWidth); // ~291 (well under 580px limit)

Validation severity levels:

• error — field is missing or critically invalid
• warning — field exists but fails recommended limits
• info — field passes all checks

Usage

Building Meta Tags

buildMetaTags() assembles a flat array of MetaTag objects from a typed SEOConfig. Frameworks render these into actual <meta> HTML elements.

import { buildMetaTags } from '@power-seo/core';

const tags = buildMetaTags({
  description: 'A TypeScript-first SEO library for modern JavaScript frameworks.',
  robots: { index: true, follow: true, maxSnippet: 150, maxImagePreview: 'large' },
  openGraph: {
    type: 'website',
    title: '@power-seo/core',
    siteName: 'My Site',
    locale: 'en_US',
    images: [{ url: 'https://example.com/og.jpg', width: 1200, height: 630, alt: 'SEO Core' }],
  },
  twitter: {
    cardType: 'summary_large_image',
    site: '@mysite',
    creator: '@author',
    image: 'https://example.com/twitter.jpg',
  },
});
// tags → MetaTag[] — pass to your framework's meta renderer

Validating Titles and Meta Descriptions

validateTitle() and validateMetaDescription() calculate the real pixel width Google uses for SERP truncation — not just character count.

import { validateTitle, validateMetaDescription } from '@power-seo/core';

const title = validateTitle('Best Running Shoes for Beginners — 2026 Guide');
// { valid: true, severity: 'info', charCount: 46, pixelWidth: 316.8 }

const meta = validateMetaDescription('Discover expert-reviewed running shoes for beginners.');
// { valid: true, severity: 'warning', charCount: 52, pixelWidth: 335.3 }
// → short (under 120 chars), suggests expanding to 120–160 chars

URL Utilities

import {
  resolveCanonical,
  normalizeUrl,
  toSlug,
  stripTrackingParams,
  extractSlug,
  isAbsoluteUrl,
} from '@power-seo/core';

resolveCanonical('https://example.com', '/blog/post');
// => "https://example.com/blog/post"

toSlug('My Blog Post Title! — 2026');
// => "my-blog-post-title-2026"

stripTrackingParams('https://example.com/page?utm_source=twitter&id=123');
// => "https://example.com/page?id=123"

extractSlug('https://example.com/blog/my-post');
// => "my-post"

Keyword Density Analysis

import { calculateKeywordDensity, analyzeKeyphraseOccurrences } from '@power-seo/core';

const density = calculateKeywordDensity('react seo', bodyHtml);
// { keyword: 'react seo', count: 4, density: 1.8, totalWords: 450 }

const occurrences = analyzeKeyphraseOccurrences({
  keyphrase: 'react seo',
  title: 'React SEO Best Practices',
  metaDescription: 'Learn React SEO...',
  content: htmlString,
  slug: 'react-seo',
  images: [{ alt: 'React SEO diagram' }],
});
// { inTitle: true, inH1: true, inFirstParagraph: true, density: 1.8, ... }

Text Statistics

import { getTextStatistics, stripHtml, getWords, getSentences } from '@power-seo/core';

const stats = getTextStatistics('<h1>Hello</h1><p>This is a test sentence. And another one.</p>');
// {
//   wordCount: 9,
//   sentenceCount: 2,
//   paragraphCount: 1,
//   syllableCount: 11,
//   characterCount: 42,
//   avgWordsPerSentence: 4.5,
//   avgSyllablesPerWord: 1.22
// }

Robots Directives

import { buildRobotsContent, parseRobotsContent } from '@power-seo/core';

buildRobotsContent({ index: false, follow: true, maxSnippet: 150, maxImagePreview: 'large' });
// => "noindex, follow, max-snippet:150, max-image-preview:large"

parseRobotsContent('noindex, follow, max-snippet:150');
// => { index: false, follow: true, maxSnippet: 150 }

Title Template Engine

import { createTitleTemplate, applyTitleTemplate } from '@power-seo/core';

const makeTitle = createTitleTemplate({ siteName: 'My Site', separator: '—' });
makeTitle('About Us'); // => "About Us — My Site"
makeTitle('Contact', { separator: '|' }); // => "Contact | My Site"

applyTitleTemplate('%title% | %siteName% — Page %page%', {
  title: 'Blog',
  siteName: 'My Site',
  page: 2,
});
// => "Blog | My Site — Page 2"

Rate Limiting

import { createTokenBucket, consumeToken, getWaitTime, sleep } from '@power-seo/core';

const bucket = createTokenBucket(60); // 60 requests per minute

async function callApi() {
  if (!consumeToken(bucket)) {
    const waitMs = getWaitTime(bucket);
    await sleep(waitMs);
  }
  // make your rate-limited API call
}

Inside a CI Content Quality Gate

Block deploys when keyword density or word count fail:

import { calculateKeywordDensity, getTextStatistics } from '@power-seo/core';

const stats = getTextStatistics(bodyHtml);
const density = calculateKeywordDensity(keyphrase, bodyHtml);

if (stats.wordCount < 300) {
  console.error(`✗ Word count too low: ${stats.wordCount} (minimum 300)`);
  process.exit(1);
}

if (density.density < 0.5 || density.density > 2.5) {
  console.error(`✗ Keyword density out of range: ${density.density}% (target 0.5–2.5%)`);
  process.exit(1);
}

API Reference

Entry Points

Meta Builder Functions

Meta Validator Functions

URL Utility Functions

Text Statistics Functions

Keyword Density Functions

Robots Builder Functions

Title Template Functions

Rate Limiting Functions

Constants

Types

Use Cases

• @power-seo packages — all 17 packages use @power-seo/core as a peer dependency for shared types, constants, and utilities
• Custom SEO libraries — build your own SEO tooling on top of core's typed primitives without starting from scratch
• Next.js / Remix apps — use buildMetaTags() and buildLinkTags() server-side in route handlers or layout components
• Content editors — validate title and meta description SERP pixel widths in real time before publishing
• CI content quality gates — check keyword density and word count programmatically in build pipelines
• eCommerce product pages — validate product titles, descriptions, and slug quality at scale
• Rate-limited API integrations — use the token bucket to respect rate limits for Google Search Console, Semrush, or Ahrefs APIs
• Headless CMS plugins — use analyzeKeyphraseOccurrences() to show Yoast-style keyphrase feedback to editors

Architecture Overview

• Pure TypeScript — no compiled binary, no native modules
• Zero runtime dependencies — ships clean with nothing else to install
• Framework-agnostic — works in any JavaScript environment with no assumptions about React, Vue, or any framework
• SSR compatible — safe to run in Next.js Server Components, Remix loaders, or Express handlers
• Edge runtime safe — no Node.js-specific APIs; runs in Cloudflare Workers, Vercel Edge, Deno Deploy
• Tree-shakeable — "sideEffects": false with named exports per module; import only what you use
• Dual ESM + CJS — ships both formats via tsup for any bundler or require() usage

Supply Chain Security

• No install scripts (postinstall, preinstall)
• No runtime network access
• No eval or dynamic code execution
• CI-signed builds — all releases published via verified github.com/CyberCraftBD/power-seo workflow
• Safe for SSR, Edge, and server environments

The @power-seo Ecosystem

All 17 packages are independently installable — use only what you need.

About CyberCraft Bangladesh

CyberCraft Bangladesh is a Bangladesh-based enterprise-grade software development and Full Stack SEO service provider company specializing in ERP system development, AI-powered SaaS and business applications, full-stack SEO services, custom website development, and scalable eCommerce platforms. We design and develop intelligent, automation-driven SaaS and enterprise solutions that help startups, SMEs, NGOs, educational institutes, and large organizations streamline operations, enhance digital visibility, and accelerate growth through modern cloud-native technologies.

© 2026 CyberCraft Bangladesh · Released under the MIT License