[Crawl-Date: 2026-04-11]
[Source: DataJelly Visibility Layer]
[URL: https://datajelly.com/blog/free-seo-tools-we-use-every-day]
---
title: Free SEO Tools We Use Every Day | Blog | DataJelly
description: A walkthrough of the free diagnostic tools we built and use daily — with real workflows showing how to diagnose a site's visibility problems in under 60 seconds.
url: https://datajelly.com/blog/free-seo-tools-we-use-every-day
canonical: https://datajelly.com/blog/free-seo-tools-we-use-every-day
og_title: DataJelly - The Visibility Layer for Modern Apps
og_description: Rich social previews for Slack & Twitter. AI-readable content for ChatGPT & Perplexity. Zero-code setup.
og_image: https://datajelly.com/datajelly-og-image.png
twitter_card: summary_large_image
twitter_image: https://datajelly.com/datajelly-og-image.png
---

# Free SEO Tools We Use Every Day | Blog | DataJelly
> A walkthrough of the free diagnostic tools we built and use daily — with real workflows showing how to diagnose a site's visibility problems in under 60 seconds.

---

We built these tools because we needed them ourselves. Every day we use them to diagnose client sites, test new features, and validate that DataJelly is doing its job. They're all free, they all run in the browser, and they don't require an account.

Here's how we actually use them — not a feature list, but real workflows that help us diagnose a site's visibility problems in under 60 seconds.

## The Toolkit at a Glance

We currently maintain 15 free SEO tools, organized into four categories:

- **Audit & Testing** — Visibility Test, Site Audit, Bot Test, SEO Diagnostic Quiz, Site Crawler
- **Validators** — Robots.txt Tester, Sitemap Validator, Structured Data Validator, SSL Checker
- **Analyzers** — Metadata Viewer, Page Speed Analyzer, HTTP Header Checker, HTTP Status Checker
- **Infrastructure** — DNS Records Viewer, Website Screenshot

You can explore all of them at [/seo-tools](https://datajelly.com/seo-tools) . Below, we'll walk through three real use cases.

## Use Case 1: "Is my site even visible?"

This is where most people start. You've built a React SPA, shipped it to production, and you want to know: can Google actually see my content?

Open the [Visibility Test](https://datajelly.com/seo-tools/visibility-test) , enter your URL, and hit run. You'll get a side-by-side comparison showing what a human sees versus what a bot sees when it visits the same page.

What to look for:

- **Big gap?** Your JavaScript isn't being rendered for bots. Prerendering will fix this.
- **Small gap?** Most of your content is visible, but some dynamic sections might be missing.
- **No gap?** You're in good shape — bots see what humans see.

This single test tells you whether you have a visibility problem. It takes about 10 seconds and answers the most important question first.

## Use Case 2: "Why does my shared link look blank?"

You share your site on Slack or LinkedIn and the preview card is empty — no title, no image, no description. This is one of the most common complaints we hear from teams shipping JavaScript-heavy apps.

**Step 1:** Open the [Social Card Preview](https://datajelly.com/seo-tools/social-card-preview) and enter the URL. Check whether your Open Graph tags (`og:title`, `og:image`, `og:description`) are present in the raw HTML response.

**Step 2:** Run the [Bot Test](https://datajelly.com/seo-tools/bot-test) on the same URL. This shows you what a specific crawler (Googlebot, GPTBot, etc.) actually receives. If the meta tags are rendered client-side only, social bots won't see them — they don't execute JavaScript.
**The fix:** Your OG meta tags need to be present in the initial HTML response — either through server-side rendering, static generation, or prerendering. If you're using React Helmet or a similar library, the tags are only injected after JavaScript runs, which is too late for social bots.

## Use Case 3: "My site is slow and I don't know why"

Performance issues often aren't in your code — they're in your infrastructure. We use two tools together to narrow this down quickly.

**First:** Run the [Page Speed Analyzer](https://datajelly.com/seo-tools/page-speed-analyzer) to get your Core Web Vitals — LCP, FID, CLS. This gives you the user-facing symptoms: is the page slow to load, slow to interact with, or visually unstable?

**Then:** Use the [HTTP Header Checker](https://datajelly.com/seo-tools/http-header-checker) to inspect the response headers. Check for:

- **Cache-Control** — Is the browser caching your assets? No caching means every visit is a full re-download.
- **Content-Encoding** — Is gzip or brotli compression enabled? Uncompressed responses can be 5–10x larger.
- **Server timing** — Some hosts add timing headers that reveal backend bottlenecks.

Often, enabling caching and compression at the hosting level cuts load time in half — no code changes required.

## The 60-Second Diagnostic

If you only have a minute and want a quick health check, here's the sequence we run:
1. [Visibility Test](https://datajelly.com/seo-tools/visibility-test) — Can bots see your content?
2. [Structured Data Validator](https://datajelly.com/seo-tools/structured-data-validator) — Is your schema markup valid?
3. [Sitemap Validator](https://datajelly.com/seo-tools/sitemap-validator) — Is your sitemap well-formed and accessible?
4. [SSL Checker](https://datajelly.com/seo-tools/ssl-checker) — Is your certificate valid and properly configured?
Four tools, under a minute. If all four pass, your fundamentals are solid. If any fail, you know exactly where to dig deeper.

## What's Next

We're continuously expanding the toolkit. Recent additions include the [HTTP Bot Comparison test](https://datajelly.com/seo-tools/bot-test) (see exactly what different crawlers receive) and the [SEO Diagnostic Quiz](https://datajelly.com/seo-tools/seo-diagnostic) (an interactive walkthrough that recommends the right tools for your situation).

Every tool is free, runs in the browser, and requires no signup. If there's a diagnostic you wish existed, [let us know](https://datajelly.com/contact) — we build what we need, and we're always looking for the next gap to fill.

Explore the full suite: [datajelly.com/seo-tools →](https://datajelly.com/seo-tools)

## Quick Test: What Do Bots Actually See?

~30 seconds

Most people guess. Don't.

Run this test and look at the actual response your site returns to bots.

1
## Fetch your page as Googlebot

Use your terminal:

`curl -A "Googlebot" https://yourdomain.com`

Look for:

- Real visible text (not just `<div id="root">`)
- Meaningful content in the HTML
- Page size (should not be tiny)

2
## Compare bot vs browser

Now test what a real browser gets:

`curl -A "Mozilla/5.0" https://yourdomain.com`

If these responses are different, Google is indexing a different page than your users see.

Stop guessing — measure it.
## Real example: 253 words vs 13,547

We see this constantly. Here's a real example from production: Googlebot saw 253 words and 2 KB of HTML. A browser saw 13,547 words and 77.5 KB. Same URL — completely different content.
[![Bot vs browser comparison showing 253 words for Googlebot vs 13,547 words for a rendered browser on the same URL](https://datajelly.com/assets/bot-comparison-proof-BSBvKXDf.png) ](https://datajelly.com/assets/bot-comparison-proof-BSBvKXDf.png)
If your HTML doesn't contain the content, Google doesn't either.
[Compare Googlebot vs browser on your site → HTTP Debug Tool](https://datajelly.com/seo-tools/http-debug)

3
## Check for common failure signals

We see this all the time in production:

- HTML under ~1KB → usually empty shell
- Visible text under ~200 characters → thin or missing content
- Missing <title> or <h1> → weak or broken page
- Large difference between bot vs browser HTML → rendering issue
## Use the DataJelly Visibility Test (Recommended)

You can run this without touching curl. It shows you:

- Raw HTML returned to bots (Googlebot, Bing, GPTBot, etc.)
- Fully rendered browser version
- Side-by-side differences in word count, HTML size, links, and content

[Run Visibility Test — Free](https://datajelly.com/#visibility-test)
## What this test tells you (no guessing)

After running this, you'll know:

- Whether your HTML is actually indexable
- Whether bots are seeing partial content
- Whether rendering is breaking in production

This is the difference between *"I think SEO is set up"* and **"I know what Google is indexing."**

If you don't understand why this happens, read: [Why Google Can't See Your SPA](https://datajelly.com/blog/why-google-cant-see-your-spa)
## If this test fails

You have three real options:

SSR

Works if you can keep it stable in production

Prerendering

Breaks with dynamic content and scale

Edge Rendering

Reflects real production output without app changes

If you do nothing, you will not rank consistently. [Learn how Edge Rendering works →](https://datajelly.com/products/edge)

This issue doesn't show up in Lighthouse. It shows up in rankings.

[Run the Test](https://datajelly.com/#visibility-test) [Ask a Question](https://datajelly.com/contact)

— Jeff
Founder, DataJelly

## Structured Data (JSON-LD)
```json
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```


## Discovery & Navigation
> Semantic links for AI agent traversal.

* [DataJelly Edge](https://datajelly.com/products/edge)
* [DataJelly Guard](https://datajelly.com/products/guard)
* [Features](https://datajelly.com/#features)
* [Pricing](https://datajelly.com/pricing)
* [Visibility Test](https://datajelly.com/visibility-test)
* [Prerendering](https://datajelly.com/prerendering)
* [Prerender Alternative](https://datajelly.com/prerender-alternative)
* [Lovable SEO](https://datajelly.com/lovable-seo)
* [Visibility Layer Guide](https://datajelly.com/guides/visibility-layer)
* [How Snapshots Work](https://datajelly.com/guides/how-snapshots-work)
* [AI SEO Platform](https://datajelly.com/ai-seo-platform)
* [Bot Detection](https://datajelly.com/bot-detection)
* [Dashboard](https://dashboard.datajelly.com/)
* [SEO Tools](https://datajelly.com/seo-tools)
* [Visibility Test](https://datajelly.com/seo-tools/visibility-test)
* [Site Audit](https://datajelly.com/seo-tools/site-audit)
* [Bot Test](https://datajelly.com/seo-tools/bot-test)
* [Social Card Preview](https://datajelly.com/seo-tools/social-card-preview)
* [Robots.txt Tester](https://datajelly.com/seo-tools/robots-txt-tester)
* [Sitemap Validator](https://datajelly.com/seo-tools/sitemap-validator)
* [Structured Data Validator](https://datajelly.com/seo-tools/structured-data-validator)
* [HTTP Header Checker](https://datajelly.com/seo-tools/http-header-checker)
* [Page Speed Analyzer](https://datajelly.com/seo-tools/page-speed-analyzer)
* [SSL Certificate Checker](https://datajelly.com/seo-tools/ssl-checker)
* [DNS Records Viewer](https://datajelly.com/seo-tools/dns-records-viewer)
* [Guides](https://datajelly.com/guides)
* [Getting Started](https://datajelly.com/guides/getting-started)
* [SPA SEO Guide](https://datajelly.com/guides/spa-seo)
* [JavaScript SEO Guide](https://datajelly.com/guides/javascript-seo)
* [SSR Guide](https://datajelly.com/guides/ssr)
* [Search Engine Crawling Guide](https://datajelly.com/guides/search-engine-crawling)
* [Lovable SEO Guide](https://datajelly.com/guides/lovable-seo)
* [AI SEO Testing Guide](https://datajelly.com/guides/ai-seo)
* [SEO Testing Guide](https://datajelly.com/guides/seo-testing)
* [SERP Tracking Guide](https://datajelly.com/guides/serp-tracking)
* [Security Testing Guide](https://datajelly.com/security)
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