
Black SEO Analyzer
io.github.sethblackv26.9.16Updated Oct 7, 2026
Audit a page or crawl a whole site for technical SEO issues, locally. Compares crawls.
Overview
Lets an assistant crawl a website or sitemap locally and report technical SEO issues such as metadata, links, performance, and structured data problems.
- What it does
- Black SEO Analyzer crawls a site from a starting URL or sitemap, using HTTP requests or a headless browser for JavaScript-heavy single-page applications. It runs analysis modules covering content, metadata, URL structure, links, images, mobile-friendliness, performance, security headers, structured data, Web Vitals, CSS, JavaScript, and internationalization, then produces warnings and recommendations. Results can be written as JSON, JSONL, XML, CSV, or HTML reports. Optional AI analyzers can send page content to Anthropic, DeepSeek, OpenAI, or Gemini for content suggestions and summaries.
- When to use it
- Useful when you want an assistant to audit a site's technical SEO and get structured, machine-readable findings, or to compare crawls over time. It suits SEO professionals and developers who want the analysis to run locally and be scriptable rather than used through a hosted dashboard.
- Requirements
- Runs as a local desktop process (Windows, macOS, or Linux) installed from a platform-specific package. A license key is required in the BLACK_SEO_ANALYZER_KEY environment variable; without it, crawling is limited to a small number of pages. Optional AI analysis needs the corresponding provider API key, such as ANTHROPIC_API_KEY, OPENAI_API_KEY, DEEPSEEK_API_KEY, or GEMINI_API_KEY. Network access to the target site is required.
Installation
In SourceWeft
- Open Black SEO Analyzer in the dashboard and add it to a workspace.
- Enable the server for the chats that should use its tools.
Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.
Other MCP clients
Follow the launch instructions in the repository.
README
Black SEO Analyzer
A powerful tool for comprehensive SEO analysis, designed for SEO professionals and developers who want to ensure their websites are optimized for both search engines and AI systems.
When run without a license you're limited in the number of pages you can crawl, but no other functionality is restricted. To purchase a license and unlock unlimited analysis power, visit Black SEO Analyzer product page.
Overview
Black SEO Analyzer is a powerful tool that keeps your website visible in both traditional search results and AI-generated responses. Good technical SEO isn't just about Google rankings—it's about making sure AI systems can find and understand your content when people ask about you.
When your site's structure and metadata are optimized correctly, you'll appear in both search results and AI conversations. Black SEO Analyzer cuts through the noise and tells you exactly what's holding your site back - without corporate buzzwords, just actionable data so you don't get left behind when someone asks an AI about exactly what you sell.
True Ownership, Not Subscription
Unlike subscription-based tools that stop working when you stop paying, Black SEO Analyzer offers genuine software ownership. Your purchase includes a legally-binding source code access guarantee if we ever discontinue the product — protecting your investment permanently.
Black SEO Analyzer License: One-Time Purchase
- Lifetime software ownership
- All future updates
- Command-line efficiency
- Source code escrow guarantee
- Unlimited URLs and sites
- All advanced features included
Installation
Please read the INSTALL.md file for installation instructions.
Windows Usage
Windows Example Usage
Basic JSON output for one site
Website with a sitemap
Single page app
HTML folder output
Linux/MacOS Usage
Linux/MacOS Example Usage
Notes:
- If the binary is not executable, you may need to run
chmod +x ./black-seo-analyzerfirst. - The examples below assume the binary is in the current directory. If it's in a different directory, you'll need to provide the full path to the binary or if it is in your PATH, you can just run
black-seo-analyzer.
Basic JSON output for one site
Website with a sitemap
Single page app
HTML folder output
Comprehensive Feature List
Core Functionality
- Command-line interface
- GUI interface
- Crawl websites starting from a specified URL
- Crawl websites using a sitemap
- Support for both static websites (HTTP requests) and Single Page Applications (SPAs) via headless browser
- Configurable concurrent request limit
- Configurable maximum page limit
- Detailed logging system
- Configurable log file location
Crawling Capabilities
- HTTP request-based crawler
- Headless browser-based crawler
- Automatic detection and extraction of links, scripts, stylesheets, images
- Sitemap parsing and processing
- Asynchronous processing for crawling and analysis
- Content hash generation (SHA1) for duplicate content detection
- Configurable crawl delay
- Respect robots.txt
- User-agent customization
- Domain extraction utility
SEO Analysis Modules
- Content Analysis
- Word count
- Keyword density analysis
- Readability analysis (Flesch-Kincaid score, syllable counting)
- Duplicate content detection
- Heading structure analysis (H1, H2, etc.)
- Extraction of content from additional tags (
<strong>,<em>, etc.)
- Metadata Analysis
- Title tag extraction and validation
- Meta description extraction and validation
- Meta keywords extraction
- Viewport meta tag validation
- Robots meta tag validation
- Canonical URL validation
- OpenGraph data extraction and analysis (og:title, og:description, og:image, etc.)
- Twitter Card data extraction and analysis (twitter:card, twitter:title, etc.)
- URL Structure Analysis
- Scheme validation (HTTPS preferred)
- Path analysis (length, character usage, keyword presence)
- Query parameter analysis (identification, potential issues)
- Fragment identifier analysis
- URL length validation
- Detection of common URL patterns (e.g., file extensions)
- Link Analysis
- Identification of internal and external links
- Anchor text analysis (length, descriptiveness)
- Async checks for link status (broken links)
- Async checks for redirects
- Async checks for large file sizes linked
- Analysis of link attributes (nofollow, target)
- Normalization and classification of URLs (internal/external)
- Image Analysis
- Alt tag presence and content analysis
- Image dimension analysis
- File size considerations
- Mobile-Friendliness Assessment
- Viewport meta tag analysis
- Touch target size and spacing analysis
- Responsive image analysis (
srcset,sizesattributes) - Font size analysis (readability on mobile)
- Media query analysis (breakpoint coverage)
- Performance Analysis
- Analysis of resource loading (scripts, stylesheets, images, fonts)
- Script loading analysis (
async,defer) - Stylesheet loading analysis
- Image loading analysis (
loading="lazy") - Font loading analysis (
font-display) - Critical rendering path analysis
- Resource hint analysis (
preload,prefetch,preconnect) - Caching header analysis (Cache-Control, Expires)
- Cache busting techniques detection
- Compression analysis (Content-Encoding)
- Identification of critical resources
- Above-the-fold content detection heuristics
- TTFB and Total Load Time recording
- Extraction of performance metrics from browser/headers
- Security Analysis
- HTTPS usage check
- Mixed content detection
- Content Security Policy (CSP) header analysis
- Form security analysis (autocomplete on sensitive fields)
- External resource integrity analysis (SRI checks)
- SSL certificate expiration check
- Structured Data/Schema Markup Validation
- JSON-LD extraction and validation
- Microdata extraction and validation
- RDFa extraction and validation
- Validation of schema properties against known types
- Detection of deprecated schema properties
- Web Vitals Metrics Analysis
- Analysis related to Largest Contentful Paint (LCP)
- Analysis related to First Input Delay (FID) / Interaction to Next Paint (INP) precursors
- Analysis related to Cumulative Layout Shift (CLS)
- Analysis related to First Contentful Paint (FCP)
- Analysis related to Time to Interactive (TTI)
- Analysis related to Total Blocking Time (TBT)
- Identification of blocking resources, long tasks, main thread work
- Analysis of image dimensions, dynamic content, font loading impact
- Calculation of an overall optimization score
- Generation of specific recommendations based on metrics
- CSS Analysis
- Identification of external and inline styles
- Analysis of stylesheet content (potential issues, complexity)
- Media query analysis (related to responsiveness)
- Basic CSS-related accessibility checks
- Basic CSS-related performance checks
- Detection of potentially duplicate CSS rules
- JavaScript Analysis
- Identification of external and inline scripts
- Analysis of script attributes (
async,defer) - Analysis of script loading patterns
- Basic security checks
- Analysis of inline script content complexity
- Analysis of event handlers
- Identification of third-party scripts
- Basic checks for deprecated JS APIs
- Internationalization Analysis
- Language declaration analysis (
langattribute) hreflangimplementation analysis- Character encoding analysis (UTF-8 preferred)
- Text direction analysis (
dirattribute) - Basic checks for locale-specific formatting issues
- Basic checks for translation completeness heuristics
- Basic checks for time zone handling heuristics
- Language declaration analysis (
- AI/LLM Analysis
- Integration with Anthropic API (requires API key)
- Ability to send page content (or parts) to LLM for analysis based on predefined prompts
- AI-Powered Content Recommendations
- Automated Meta Description Generation
- Title Tag Optimization Suggestions
- Header Structure Recommendations
- Content Expansion Suggestions
- Executive Summary Generation
Output Formats
- JSON output format
- JSONL (JSON Lines) output format
- XML output format
- CSV output format
- HTML report format
- Individual JSON files per page
- HTML folder output with index and individual page reports
Reporting Features
- Detailed warnings and recommendations generated by individual analyzers
- Collection of page-level metadata
- Collection of page content details (headings, etc.)
- Collection of page resources (links, scripts, styles, images)
- Collection of Web Vitals analysis results
- Performance metrics reporting (TTFB, Load Time)
- Template-based HTML report generation
Internationalization
- Multi-language support for UI text and report labels
- Built-in translations (English, Spanish, Chinese)
- Extensible translation system
- Locale used for specific recommendations
Licensing System
- Trial mode with limited functionality
- Licensed mode with full functionality
- License validation system
- Different license tiers affecting functionality
Technical Details
- Built in Rust and C++
- Asynchronous architecture
- HTML parsing and DOM manipulation
- Headless Chrome integration
- HTTP client
- Serialization/Deserialization
- Custom URL serialization wrapper
- Utility for creating safe filenames from URLs
- Command-line argument parsing
- Templating engine for HTML report generation
Frequently Asked Questions
What makes Black SEO Analyzer different from other SEO tools?
Unlike traditional SEO tools with browser-based interfaces and subscription models, Black SEO Analyzer is a tool that integrates directly into your development workflow. This approach enables automation capabilities that aren't possible with other tools, plus you genuinely own the software with a one-time purchase.
How does the source code guarantee work?
Your purchase includes a legally-binding commitment that gives you access to the full source code if we ever discontinue the product, cease operations, or fail to provide updates for 12+ consecutive months. This ensures you can continue using the software indefinitely, regardless of our company's future.
Can Black SEO Analyzer crawl JavaScript-heavy sites?
Yes, our integrated headless browser technology provides full JavaScript rendering capabilities. This ensures accurate analysis of modern web applications built with React, Angular, Vue.js, and other JavaScript frameworks.
How are updates handled?
Updates are provided via our GitHub repository and can be downloaded at any time. You'll receive all future updates at no additional cost. Life-time ownership.
Source: README.md at commit 526a17d
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0Version history
1- v26.9.16LatestOct 7, 2026