Using JavaScript SEO testing tools helps website owners, developers, and SEO professionals identify and fix these issues.
As we know JavaScript SEO is an essential aspect of technical SEO that focuses on ensuring that JavaScript-powered websites are crawled, indexed, and rendered properly by search engines.
Search engines like Google use two-phase indexing: first, they process static HTML, and later, they render JavaScript.
If your JavaScript prevents important content from being crawled, it could lead to indexing issues.
Common problems include lazy loading failures, blocked scripts, and content not appearing in the rendered version of the page.
These JavaScript testing tools analyze rendered pages, check for blocked resources, test structured data, and verify how search engine crawlers interpret JavaScript-powered content.
JavaScript SEO Testing Tools for Better Crawling
Here are some of the JavaScript Analysing tools to Consider for your Technical SEO:
1. Google Search Console (URL Inspection Tool)
Google Search Console provides an essential tool for testing JavaScript SEO: the URL Inspection Tool.
This tool allows webmasters to check how Googlebot crawls, renders, and indexes JavaScript-powered pages.
It displays a side-by-side comparison of the raw HTML and rendered version of a page, helping users identify missing content, JavaScript execution issues, and indexing problems.
Top Features:
- Live URL inspection for real-time testing
- Screenshot of Google’s rendered page
- Indexing status and structured data validation
- Mobile-friendliness and Core Web Vitals analysis
- JavaScript error reporting
Pros:
✔️ Free to use and easy to access
✔️ Direct insights from Google’s own crawler
✔️ Helps debug indexing and JavaScript rendering issues
Cons:
❌ Limited to testing one page at a time
❌ Doesn’t provide detailed JavaScript execution logs
| Attribute | Details |
| Launch Date | 2015 (rebranded) |
| Starting Price | Free |
| Capabilities | Live testing, rendering check, indexing analysis |
| Public Reception | Highly regarded for direct Google insights |
| Best For | Quick JavaScript SEO debugging |
| Limitations | One-page testing only |
2. Google Mobile-Friendly Test
Google Mobile-Friendly Test is a free online tool that evaluates whether a web page is optimized for mobile devices.
Since JavaScript can affect mobile usability by delaying rendering or hiding content, this tool helps identify issues that could harm SEO performance.
By analyzing how Googlebot sees a page, it detects mobile compatibility problems, slow-loading scripts, and blocked resources.
Top Features:
- Analyzes mobile usability for JavaScript-powered pages
- Displays a rendered version of the page
- Highlights loading issues and blocked resources
- Provides suggestions to improve mobile experience
- Checks viewport configuration and text readability
Pros:
✔️ Free and easy to use
✔️ Direct feedback from Google’s mobile crawler
✔️ Helps diagnose JavaScript rendering problems on mobile
Cons:
❌ Only tests one page at a time
❌ No deep-level JavaScript debugging
| Attribute | Details |
| Launch Date | 2016 |
| Starting Price | Free |
| Capabilities | Mobile-friendliness analysis, JavaScript rendering check |
| Public Reception | Widely used for quick mobile SEO checks |
| Best For | Testing JavaScript-heavy mobile pages |
| Limitations | Single-page analysis only |
3. Screaming Frog SEO Spider
Screaming Frog SEO Spider is a powerful desktop-based crawling tool that mimics search engine bots, including JavaScript execution.
It allows SEO professionals to test how JavaScript affects website crawling, indexing, and rendering.
The tool can detect missing content, broken links, duplicate pages, and JavaScript-based rendering issues.
Top Features:
- JavaScript rendering with simulated Googlebot behavior
- Identifies missing meta tags, titles, and content
- Checks for blocked resources and crawl issues
- Analyzes structured data and canonical tags
- Generates detailed crawl reports
Pros:
✔️ Comprehensive SEO and JavaScript crawling analysis
✔️ Exportable reports for large-scale auditing
✔️ Works with dynamic and single-page applications (SPAs)
Cons:
❌ Requires setup and some technical knowledge
❌ Free version has a crawl limit of 500 URLs
| Attribute | Details |
| Launch Date | 2010 |
| Starting Price | Free (500 URL limit), Paid: £209/year |
| Capabilities | JavaScript rendering, technical SEO audits, structured data analysis |
| Public Reception | Highly rated for in-depth SEO analysis |
| Best For | Enterprise-level SEO audits |
| Limitations | Steeper learning curve, paid version needed for full access |
4. Sitebulb
Sitebulb is an advanced website auditing tool that offers deep insights into JavaScript SEO issues.
It provides a detailed visualization of how Googlebot renders JavaScript pages, highlighting areas where content may be hidden or blocked.
It also includes insights into Core Web Vitals, structured data, and internal linking.
Top Features:
- JavaScript rendering with full DOM analysis
- Page speed and Core Web Vitals insights
- Crawl visualization for JavaScript-heavy sites
- Automated SEO suggestions
- Exportable reports for teams
Pros:
✔️ User-friendly interface with detailed reports
✔️ Great for visualizing crawl and rendering issues
✔️ Offers deep JavaScript performance insights
Cons:
❌ Requires installation (not cloud-based)
❌ No free version, only a free trial
| Attribute | Details |
| Launch Date | 2017 |
| Starting Price | $13.50/month |
| Capabilities | JavaScript rendering, technical SEO, Core Web Vitals analysis |
| Public Reception | Popular among SEO agencies for in-depth audits |
| Best For | Visualizing JavaScript SEO issues |
| Limitations | Requires local installation |
5. Google Rich Results Test
Google’s Rich Results Test helps evaluate whether JavaScript-powered structured data is correctly implemented on a webpage.
Since JavaScript can sometimes interfere with structured data visibility, this tool is essential for testing schema markup.
It verifies whether Google can recognize and use rich snippets such as FAQs, reviews, and product details.
Top Features:
- Validates structured data on JavaScript-powered sites
- Supports multiple schema types (FAQ, reviews, products, etc.)
- Displays rendered page version with structured data highlights
- Provides debugging recommendations for errors
Pros:
✔️ Free and easy to use
✔️ Directly tests how Google sees structured data
✔️ Helps improve rich snippet eligibility
Cons:
❌ Limited to structured data testing only
❌ Doesn’t analyze other JavaScript rendering issues
| Attribute | Details |
| Launch Date | 2020 |
| Starting Price | Free |
| Capabilities | Structured data validation, JavaScript rendering check |
| Public Reception | Widely used for schema markup validation |
| Best For | Ensuring structured data visibility in JavaScript |
| Limitations | No full JavaScript SEO analysis |
6. Google Lighthouse
Google Lighthouse is an open-source tool designed to audit web pages for performance, accessibility, best practices, SEO, and Progressive Web App standards.
It provides detailed insights into JavaScript execution times, page speed issues, and how Googlebot renders JavaScript-heavy pages.
Lighthouse is integrated into Chrome DevTools, making it a convenient choice for testing JavaScript SEO issues.
Top Features:
- JavaScript execution and render-blocking script analysis
- Core Web Vitals and page speed performance metrics
- SEO audit including mobile-friendliness and metadata checks
- Detailed recommendations for improving page load speed
- Available via Chrome DevTools, CLI, and PageSpeed Insights
Pros:
✔️ Free and open-source
✔️ Easy to use for quick performance and SEO insights
✔️ Provides actionable recommendations
Cons:
❌ Lacks deep crawling capabilities
❌ Doesn’t provide a full JavaScript rendering report
| Attribute | Details |
| Launch Date | 2016 |
| Starting Price | Free |
| Capabilities | JavaScript execution analysis, SEO audit, Core Web Vitals testing |
| Public Reception | Highly rated for page speed and SEO insights |
| Best For | Quick JavaScript SEO performance checks |
| Limitations | No deep crawling analysis |
7. JetOctopus
JetOctopus is a cloud-based SEO crawler that specializes in JavaScript rendering. It provides in-depth insights into how Googlebot crawls and indexes JavaScript-heavy sites.
Unlike other crawlers, it processes full JavaScript execution, making it ideal for Single Page Applications (SPAs) and modern frameworks like React and Angular.
Top Features:
- JavaScript rendering with dynamic content analysis
- Crawl visualization and indexing reports
- Structured data validation and Core Web Vitals insights
- JavaScript performance monitoring
- Cloud-based (no installation required)
Pros:
✔️ Fast cloud-based crawling for large sites
✔️ Great for analyzing JavaScript-heavy frameworks
✔️ Provides detailed indexing insights
Cons:
❌ Requires a paid subscription
❌ Slight learning curve for new users
| Attribute | Details |
| Launch Date | 2019 |
| Starting Price | $30/month |
| Capabilities | Full JavaScript rendering, technical SEO analysis |
| Public Reception | Popular for JavaScript-based site auditing |
| Best For | Large-scale JavaScript SEO audits |
| Limitations | Paid-only service |
8. DeepCrawl (Lumar)
DeepCrawl (now rebranded as Lumar) is an enterprise-level SEO crawler that offers full JavaScript rendering capabilities.
It helps businesses analyze how search engines interact with JavaScript-based sites and provides actionable insights to optimize indexing and performance.
Top Features:
- Full JavaScript rendering with Googlebot simulation
- Crawl budget and indexing analysis
- Mobile and desktop crawling comparisons
- Structured data validation and site architecture analysis
- API integrations with Google Search Console and other tools
Pros:
✔️ Enterprise-level crawling capabilities
✔️ Ideal for large, complex websites
✔️ Provides JavaScript rendering insights at scale
Cons:
❌ Expensive for small businesses
❌ Requires some technical knowledge
| Attribute | Details |
| Launch Date | 2010 |
| Starting Price | Custom pricing |
| Capabilities | Enterprise-level crawling, JavaScript SEO analysis |
| Public Reception | Highly rated for large-scale technical SEO |
| Best For | Enterprise JavaScript SEO |
| Limitations | Expensive for small websites |
9. OnCrawl
OnCrawl is a cloud-based SEO crawler that specializes in analyzing JavaScript rendering, indexing, and performance.
It provides deep insights into how search engines interpret JavaScript-powered pages and integrates machine learning to offer predictive SEO analysis.
Top Features:
- JavaScript rendering with full DOM analysis
- Crawl budget optimization and internal linking insights
- Log file analysis to track bot behavior
- Customizable dashboards and API integrations
- Predictive SEO recommendations using AI
Pros:
✔️ AI-powered insights for JavaScript SEO
✔️ Log file analysis for tracking Googlebot behavior
✔️ Great for enterprise-level audits
Cons:
❌ High cost for small businesses
❌ Requires technical knowledge for advanced features
| Attribute | Details |
| Launch Date | 2013 |
| Starting Price | $49/month |
| Capabilities | JavaScript SEO analysis, log file tracking, AI-driven insights |
| Public Reception | Well-regarded for advanced SEO auditing |
| Best For | Technical SEO experts handling large websites |
| Limitations | Expensive for smaller projects |
10. BrowSEO
Browseo is a web app designed to help you view any webpage without distractions from styles, showing the raw HTML that search engines see.
It highlights key elements important for search optimization, such as server response codes, redirects, word count, headings, and internal and external links.
By focusing on what search engines prioritize, Browseo lets you quickly analyze a page’s structure and relevance for specific search terms. No installation is needed—just enter a URL to start using it.
Top Features:
- JavaScript stripping to analyze crawlable content
- Meta tag and structured data insights
- Internal link analysis and duplicate content detection
- Simulated search engine view of web pages
Pros:
✔️ Great for quick JavaScript SEO checks
✔️ Helps detect hidden content issues
✔️ No installation required (browser-based)
Cons:
❌ Limited to surface-level analysis
❌ No full JavaScript execution testing
| Attribute | Details |
| Launch Date | 2015 |
| Starting Price | Free (Paid: $19/month) |
| Capabilities | Basic JavaScript SEO visibility analysis |
| Public Reception | Useful for quick technical SEO checks |
| Best For | Detecting hidden content issues |
| Limitations | Lacks full JavaScript execution testing |
Conclusion
JavaScript SEO testing tools help developers and SEO experts ensure that search engines can properly render, crawl, and index JavaScript-heavy websites. Whether you need quick insights (Google Search Console, Lighthouse) or enterprise-level audits (DeepCrawl, JetOctopus), these tools provide critical data for optimizing your site’s visibility.
FAQs
1. Why is JavaScript SEO important?
JavaScript SEO ensures that search engines can properly crawl, render, and index JavaScript-powered content. Without optimization, important content may not be indexed, leading to lower search rankings.
2. What are common JavaScript SEO issues?
Common issues include blocked JavaScript files, delayed rendering, missing structured data, lazy loading failures, and poor mobile usability due to script execution delays.
3. How do search engines handle JavaScript?
Search engines like Google use a two-phase process: first, they crawl static HTML, and later, they render JavaScript. If important content is only visible after rendering, it may take longer to be indexed.
4. Which JavaScript SEO tool is best for beginners?
Google Search Console (URL Inspection Tool) and Google Lighthouse are great starting points as they are free and provide direct insights from Google.
5. Do JavaScript SEO tools require coding knowledge?
Some tools, like Screaming Frog and JetOctopus, require basic technical knowledge. However, Google Search Console and Google Lighthouse are user-friendly and require minimal coding experience.
