Free SEO tools — meta tags, headings, images, keywords, and a full site audit. No signup.
Free SEO tools — meta tags, headings, images, keywords, and a full site audit. No signup.
CheckSEO is a collection of 84 free tools for website owners, developers, marketers, and YouTube creators. Paste a URL and see exactly what search engines see: your title and meta tags, heading structure, image alt text, canonical and hreflang tags, redirects, robots.txt, sitemap, Core Web Vitals, structured data, and security headers. Every check explains what it found, why it matters, and how to fix it.
There is no signup and no paywall on any tool. The Full Site Audit runs the on-page and technical checks together and gives you one score to start from; the individual tools let you dig into a single issue. Alongside the tools, the blog has in-depth guides written by the developer who built them.
Run every check at once and get one score to start from.
6 tools
Title tags, headings, images, and content — what search engines read first.
10 tools
Redirects, sitemaps, and crawl rules — the plumbing search engines depend on.
17 tools
DNS, certificates, headers, and registration — what's true about a domain before any page loads.
7 tools
Generate the JSON-LD markup search engines use for rich results.
8 tools
How your links actually look when they're shared.
5 tools
General-purpose tools that don't need a URL at all.
15 tools
For creators — no API key, no login.
16 tools
Check title, description, canonical, Open Graph, and Twitter Card tags.
Check a page's H1 and its full H1–H6 heading structure.
Find images missing alt text across a page.
Compare two URLs and see how much of their visible text actually overlaps.
Extract every link's anchor text on a page and flag generic, non-descriptive links like "click here".
Check a domain's IP against public DNS blacklists used for spam and reputation filtering.
Scan a page's links and find the ones that return 404s, errors, or time out.
Run every on-page and technical SEO check against a URL in one pass.
See exactly how a title and meta description will look in Google results before you publish.
Run a real Lighthouse check and see actual LCP, CLS, and INP — lab data plus real-world Chrome UX Report field data, when available.
Check a domain's SPF, DKIM, and DMARC setup and see exactly what's missing or misconfigured.
Get the real phrases people type into Google for any seed keyword, pulled from autocomplete.
Find out when a domain was first registered, when it expires, and who the registrar is.
Find every JSON-LD block on a page and check it parses, has a @type, and is ready for rich results.
Build JSON-LD for Article, Product, LocalBusiness, Organization, Event, Video, HowTo, and Breadcrumb.
Generate title, description, Open Graph, and Twitter Card tags from a form, with a live search preview.
Look up any public channel or video, write titles, tags, descriptions and hashtags, and grab thumbnails, logos and banners. No API key and no login — it works from public data only.
Estimate ad-revenue earnings from your views, upload rate, and niche.
Download any video's thumbnail in every resolution YouTube stores.
Turn a video title or topic into a ready-to-paste tag list.
Resolve any channel URL or @handle to its real UC... channel ID.
Reveal the hidden tags any public YouTube video was uploaded with.
Drop your topic into a dozen proven title patterns, each with a length check against what YouTube shows.
Turn what your video covers into a structured description with chapters, links, and hashtags.
Build a hashtag set from a title or topic, ordered so the three YouTube displays come first.
Pull any public video's full description, exact title, channel, date, views, and length.
Download any channel's profile picture at full 800px resolution or the smaller sizes YouTube uses.
Responsive, privacy-enhanced embed code with start time, autoplay, loop, and control options.
Views, publish date, length, engagement rate, and tags for any public video.
Subscriber count, total views, video count, and channel age for any public channel.
Turn a channel URL or @handle into a one-click subscribe link.
See which countries can and can't watch a public video.
Download any channel's banner art at the largest resolution YouTube stores.
Check whether your IP or domain is on a spam blacklist (DNSBL), what each listing means, and how to get delisted. Free blacklist checker included.
5 min read
Instagram caption character limit is 2,200, but the feed cuts it far sooner. Every 2026 limit for X, Threads, LinkedIn, Facebook and TikTok in one table.
6 min read
Social media image sizes for 2026, checked against official help pages: Instagram, Facebook, X, LinkedIn, TikTok, YouTube and Pinterest, with safe zones.
6 min read
JWT online decoder guide: what a JSON Web Token is, how to decode its header and payload, how to read exp and iat, and what never to put in one.
7 min read
Alternate page with proper canonical tag in Search Console usually needs no fix. Learn to read it, spot a wrong canonical, and check the canonical chain.
6 min read
Hreflang tags explained: syntax, x-default, language and region codes, sitemap and HTTP header setup, and the missing return link that makes Google ignore them.
6 min read