Free SEO Tools for Every Part of Your Workflow
Search engine optimization covers a wide surface area โ from the words on your page to the HTTP headers your server sends. The tools on this page are organized around the four main workflows in a typical SEO audit: on-page optimization, technical health, content quality, and structured data implementation.
Every tool here runs entirely in your browser. Nothing is sent to a server, no account is required, and there are no usage limits. For teams that handle large-scale crawls or automated reporting, these tools complement (rather than replace) paid platforms like Screaming Frog, Ahrefs, or SEMrush.
On-Page SEO Tools
The SERP Preview Tool renders an accurate simulation of how your page appears in Google search results on both desktop and mobile, with real-time character warnings as your title or description approaches truncation limits. It's the fastest way to validate your metadata before publishing.
The Meta Tag Analyzer goes deeper โ paste your full page HTML or a URL and it extracts every SEO-relevant tag: title, meta description, canonical, Open Graph, Twitter Card, and robots directives. Each element is scored and flagged for common issues like missing tags, duplicate values, or out-of-range lengths.
Technical SEO Tools
The Robots.txt Tester lets you paste any robots.txt file and test individual URLs against its rules. It shows you exactly which user-agent directives apply, whether the URL is allowed or blocked, and which specific rule matched โ eliminating the guesswork of manual parsing.
The Redirect Checker simulates a redirect chain from any starting URL and shows the full sequence of status codes (301, 302, etc.), the final destination, and any redirect loops. Chains longer than three hops carry a performance and crawl-budget warning.
The Broken Link Checker accepts pasted HTML or a list of URLs, extracts all hyperlinks, and categorizes them by type (internal, external, anchor). It's particularly useful for content audits when you want a fast inventory of all outgoing links before running a full crawler.
The Core Web Vitals Checker is a guided reference tool that explains LCP, CLS, INP, and FCP โ the metrics Google's Page Experience algorithm uses โ with clear pass/fail thresholds, common causes for each failure mode, and direct links to PageSpeed Insights and CrUX for real-field data.
Content Quality Tools
The Plagiarism Checker compares two blocks of text using n-gram phrase matching and returns a similarity percentage along with highlighted matched phrases on both sides. It's designed for content editors who need a quick pre-publish check, not a legal plagiarism determination.
The Readability Score Checker calculates four industry-standard readability metrics simultaneously: Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, and SMOG Index. A target audience selector (General, Blog, Academic, Children) adjusts the benchmarks so the scores are interpreted in context.
The Email Subject Line Tester โ useful for SEO teams managing newsletter campaigns โ previews your subject line exactly as it will appear in Gmail, Outlook, and mobile clients, including truncation. It scores the subject line on factors like length, spam trigger words, personalization tokens, and preview text optimization.
Structured Data & International SEO
The Structured Data / Schema Generator provides a visual form-based interface for generating valid JSON-LD markup for the most commonly used schema types: Article, Product, FAQ, Local Business, BreadcrumbList, Event, Recipe, and more. The output is copy-paste ready for your <head> or before the closing </body> tag.
The Hreflang Tag Generator handles one of the most error-prone areas of international SEO. Add your pages with their language and region variants, and the tool outputs a complete set of <link rel="alternate" hreflang="..."> tags โ including the required x-default โ ready to paste into each page's <head>.