SEO Tools

Search engine optimization spans technical implementation, content strategy, and off-page signals. The right SEO tools help you monitor your search presence, identify technical issues that prevent indexing, optimize on-page elements, and track your competitive position. This lesson covers both essential free tools that every site should use and professional paid platforms for teams that need deeper analysis. Whether you are a developer focused on technical SEO or a marketer tracking keyword rankings, there is a tool here for you.

Essential Free Tools

Google Search Console

Pricing: Free — Platform: Web

Google Search Console (GSC) is the single most important SEO tool available, and it is completely free. GSC provides direct data from Google about how your site appears in search results, including which queries drive traffic, your average position for each query, click-through rates, and impression counts. No third-party tool can match this data because it comes directly from Google's index.

Beyond search performance data, GSC provides critical technical SEO information: indexing status for every page, Core Web Vitals reports based on real user data, mobile usability issues, structured data validation, security issues, and manual actions. It also allows you to submit sitemaps, request indexing of new or updated pages, and inspect how Googlebot sees any URL on your site.

Best use cases

• Monitoring search performance (queries, clicks, impressions, position)
• Identifying indexing issues and requesting re-indexing
• Checking Core Web Vitals based on real user data
• Validating structured data and rich results eligibility
• Submitting and monitoring XML sitemaps

Google Rich Results Test

Pricing: Free — Platform: Web

Google Rich Results Test checks whether your structured data (JSON-LD, Microdata, or RDFa) is valid and eligible for rich results in Google Search. Rich results include recipe cards, FAQ accordions, product ratings, event listings, breadcrumbs, and many other enhanced search appearances that significantly improve click-through rates.

The tool validates your structured data against Google's requirements, which are stricter than Schema.org's general specification. It shows warnings for recommended properties that are missing and errors for required properties. You can test a live URL or paste code directly.

Best use cases

• Validating structured data before deploying to production
• Debugging why rich results are not appearing in search
• Checking which rich result types your pages are eligible for

CodeFrog

Pricing: $99/year — Platform: Desktop app (Mac and Windows)

CodeFrog includes a comprehensive SEO audit as part of its mega report. It validates meta tags (title, description, robots), checks Open Graph and Twitter Card tags for correct social sharing previews, verifies canonical URLs, checks for duplicate titles and descriptions, and validates that structured data is present and well-formed.

The ability to test localhost is particularly valuable for SEO because it lets you verify that meta tags, structured data, and Open Graph tags are correct before deploying. Catching SEO issues in development is much better than discovering them after Google has already crawled and indexed incorrect metadata.

Best use cases

• Validating meta tags and Open Graph tags on localhost before deployment
• Comprehensive SEO audit alongside accessibility, security, and performance
• Checking social sharing preview tags (OG and Twitter Cards)
• Verifying canonical URLs and robots directives

Site Crawlers

Screaming Frog SEO Spider

Pricing: Free (up to 500 URLs); $279/year (unlimited) — Platform: Desktop (Java, runs on Mac, Windows, Linux)

Screaming Frog SEO Spider is a website crawler that analyzes on-site SEO by crawling your site the same way search engines do. It collects data on every page including titles, meta descriptions, heading structure, canonical tags, hreflang tags, response codes, redirect chains, and much more. The free version crawls up to 500 URLs, which is sufficient for most small to medium sites.

Screaming Frog excels at finding technical SEO issues at scale. It identifies broken links, redirect chains, duplicate content, missing tags, orphan pages (not linked from anywhere), and pages blocked by robots.txt or noindex. For large sites, the paid version adds JavaScript rendering, crawl scheduling, Google Analytics integration, and API access.

Best use cases

• Comprehensive technical SEO audits of entire sites
• Finding broken links, redirect chains, and duplicate content
• Analyzing heading structure and meta tag coverage across all pages
• Pre-launch site audits to catch SEO issues before going live
• Comparing crawl results before and after site migrations

Comprehensive SEO Platforms

Ahrefs

Pricing: From $99/month (Lite) — Platform: Web

Ahrefs is best known for its backlink analysis, which is powered by one of the largest web crawlers in the world (second only to Google). Its Site Explorer shows every backlink pointing to your site or any competitor's site, including the anchor text, referring domain authority, and whether the link is followed or nofollowed. This data is essential for link-building strategy and competitive analysis.

Beyond backlinks, Ahrefs provides keyword research (search volume, keyword difficulty, click-through rate estimates), content explorer (find popular content in any niche), rank tracking, and a site audit tool that crawls your site for technical SEO issues. The Keywords Explorer tool shows related keywords, questions, and search suggestions that help you plan content strategy.

Best use cases

• Backlink analysis and link-building strategy
• Competitive analysis (comparing your backlink profile to competitors)
• Keyword research and content planning
• Tracking keyword rankings over time

Semrush

Pricing: From $129.95/month (Pro) — Platform: Web

Semrush is the most comprehensive all-in-one SEO platform. It combines keyword research, site auditing, rank tracking, backlink analysis, competitor analysis, content optimization, and PPC research in a single tool. Its site audit feature crawls your site and identifies over 140 types of technical SEO issues, prioritized by impact.

Semrush's competitive analysis features are particularly powerful. You can see which keywords your competitors rank for that you do not, identify content gaps, analyze their backlink strategies, and track their ranking changes over time. The Content Marketing Toolkit helps optimize content for target keywords and tracks content performance.

Best use cases

• Comprehensive SEO management for agencies and teams
• Competitive analysis and gap identification
• Content optimization with target keyword integration
• Combined SEO and PPC strategy management

Moz

Pricing: From $99/month (Standard); free tools available — Platform: Web, browser extension

Moz pioneered the concept of Domain Authority (DA), a metric that predicts how well a domain will rank in search results. While Domain Authority is a proprietary metric (not used by Google), it is widely used in the SEO industry as a benchmark for comparing sites. Moz provides keyword research, rank tracking, site crawling, and backlink analysis.

The free MozBar browser extension is particularly useful — it shows Domain Authority and Page Authority for any site you visit, displays link metrics in search results, and provides quick access to on-page SEO elements. Moz's Link Explorer provides backlink data, and their Keyword Explorer offers unique metrics like keyword difficulty and organic CTR estimates.

Best use cases

• Domain Authority benchmarking and tracking
• Quick SEO metrics while browsing (MozBar extension)
• Teams that value Moz's educational resources and community
• Link analysis with Domain Authority context

CMS and Platform-Specific Tools

Yoast SEO

Pricing: Free plugin; Premium from $99/year — Platform: WordPress

Yoast SEO is the most popular WordPress SEO plugin, installed on over 13 million sites. It provides a content analysis tool that checks your posts and pages against SEO best practices as you write, including keyword density, meta description length, heading usage, internal linking, and readability. Yoast also generates XML sitemaps, manages canonical URLs, and handles technical SEO settings that WordPress does not provide natively.

Best use cases

• WordPress sites that need SEO without technical configuration
• Content creators who want real-time SEO guidance while writing
• Automatic XML sitemap generation and management

Structured Data and Social Preview Tools

Schema.org Validator

Pricing: Free — Platform: Web

Schema.org Validator checks your structured data against the Schema.org vocabulary. While the Google Rich Results Test validates against Google's specific requirements, the Schema.org Validator checks against the full vocabulary, catching issues that might affect other search engines or consuming applications. Use both tools for complete structured data validation.

Best use cases

• Validating structured data against the full Schema.org specification
• Ensuring compatibility with search engines beyond Google
• Testing complex structured data types not covered by Google's rich results

Facebook Sharing Debugger

Pricing: Free — Platform: Web (requires Facebook login)

Facebook Sharing Debugger shows exactly how your page will appear when shared on Facebook and other platforms that use Open Graph tags. It displays the title, description, and image that will be used, and highlights any issues with your Open Graph markup. Importantly, it also lets you scrape new information — if you have updated your OG tags, you can force Facebook to re-fetch them instead of using cached data.

Best use cases

• Testing how URLs will appear when shared on social media
• Debugging Open Graph tag issues (wrong image, missing description)
• Forcing Facebook to refresh cached OG data after updates
• Verifying og:image dimensions and format requirements