Hreflang Checker Pro

Hreflang Checker Pro is the most complete hreflang audit tool available as a Chrome extension. Built for SEO professionals, technical SEOs, international SEO specialists, and webmasters managing multilingual and multi-regional websites, this extension gives you a full diagnostic of every hreflang tag on any page — in seconds.
No login. No account. No data sent to any server. Everything runs locally in your browser.

🌐 WHAT IS HREFLANG AND WHY DOES IT MATTER?
Hreflang is an HTML attribute used to tell search engines like Google which version of a page to serve to users based on their language and region. When implemented correctly, hreflang signals help your international pages rank in the right countries and languages. When implemented incorrectly, it causes duplicate content confusion, ranking drops, wrong-language pages appearing in search results, and wasted crawl budget.
Common hreflang mistakes include:

Missing self-referencing hreflang tags
Missing x-default tags
Invalid ISO 639-1 language codes
Broken reciprocal (return) links between language variants
Relative URLs instead of absolute URLs
Duplicate language codes on the same page
HTTP errors (404, 301, 500) on linked hreflang target pages
JavaScript-injected hreflang that search engines cannot reliably read

All of these are exactly what Hreflang Checker Pro is designed to detect.

✅ CORE FEATURES
▸ COMPLETE HREFLANG TAG AUDIT
Scans every <link rel="alternate" hreflang="..."> tag on the current page and presents them in a clean, sortable table. See the language code, target URL, HTTP status, and return link status for every tag at a glance.
▸ RECIPROCAL LINK VALIDATION
One of the most critical — and most overlooked — hreflang requirements is that every linked page must link back to the original. Hreflang Checker Pro automatically fetches each target URL and checks whether it contains a return link pointing back to the current page. This is the same validation process used by professional SEO audit platforms, now available as a free browser extension.
▸ LIVE HTTP STATUS CHECKING
Each hreflang target URL is checked for its HTTP response code. The extension clearly flags 200 OK, 301/302 redirects, 404 not found, 500 server errors, and network failures — so you can immediately see which language variants are broken or redirecting to unintended destinations.
▸ SSR vs JS DETECTION
A critical but often-missed issue: hreflang tags that are injected by JavaScript rather than present in the raw server-rendered HTML may not be reliably picked up by Google. Hreflang Checker Pro detects whether each tag is server-side rendered (SSR) or JavaScript-injected (JS) and badges each row accordingly. If your tags are JS-injected, this is an important signal to investigate.
▸ LANGUAGE CODE VALIDATION
The extension validates every hreflang attribute value against the full ISO 639-1 language code list, including regional variants (e.g. en-GB, zh-TW, pt-BR) and the special x-default tag. Invalid or misspelled language codes are immediately flagged as errors.
▸ SELF-REFERENCE DETECTION
Google requires that hreflang tag sets include a self-referencing tag — a tag pointing back to the current page itself. Missing self-references are one of the most common hreflang implementation mistakes. The extension detects this instantly and flags it as a warning.
▸ X-DEFAULT DETECTION
The x-default tag tells Google which page to serve when no other language variant matches a user's preference. Hreflang Checker Pro checks whether your tag set includes an x-default entry and flags it as missing if not present.
▸ RELATIVE URL DETECTION
Hreflang URLs must be absolute (e.g. https://example.com/en/), not relative (e.g. /en/). The extension detects all relative hreflang URLs and flags them as warnings, since relative URLs may cause incorrect canonicalization in some implementations.
▸ DUPLICATE LANGUAGE CODE DETECTION
Having two or more hreflang tags with the same language code on a single page is an implementation error that can confuse search engines. The extension detects all duplicate lang codes and reports them as errors.
▸ ISSUES TAB WITH CATEGORISED ERRORS AND WARNINGS
Every detected problem is listed in a dedicated Issues tab, clearly separated into Errors (critical issues) and Warnings (best-practice violations). Each issue includes the specific language code it relates to, making it easy to know exactly what to fix.
▸ REAL-TIME PROGRESS INDICATOR
As the extension checks reciprocal links in the background, a live progress bar shows how many URLs have been verified so far. You can see results updating in real time as each check completes.
▸ DYNAMIC TOOLBAR ICON STATES
The extension icon in your Chrome toolbar changes colour based on the audit result — giving you an at-a-glance status on every page you visit:
– Grey — scanning, or no hreflang tags found on this page
🟢 Green — all hreflang tags valid, no issues detected
🟠 Orange — warnings (e.g. missing x-default, redirects)
🔴 Red — errors (e.g. invalid lang codes, missing return links, HTTP errors)
▸ SORT AND FILTER
Sort the tag table by: Default order, Language code (A–Z), HTTP Status, Return link status, or Issues First. Filter by language code or URL using the live search bar. Makes it easy to zero in on specific languages or problems in large hreflang sets.
▸ CSV EXPORT
Export the full hreflang audit to a CSV file with a single click. The export includes all tag data: language code, raw URL, resolved URL, render source (SSR/JS), self-reference flag, validity flag, HTTP status, return link status, redirect flag, and any error messages. The filename is automatically set to include the hostname and date (e.g. hreflang-apple.com-2026-03-24.csv), making it easy to save and share audit reports with clients or team members.
▸ SETTINGS — CUSTOMISE YOUR WORKFLOW
• Toggle auto-checking of reciprocal links on or off
• Adjust the number of concurrent requests (1–10) for return link checking
• Toggle row highlighting for issue rows
All settings are persisted locally using Chrome's storage API.

👥 WHO IS THIS FOR?
Hreflang Checker Pro is built for:

Technical SEO Professionals — quickly audit hreflang implementation on client websites during technical audits without needing to pull up multiple tools or write custom scripts.
International SEO Specialists — validate that your multilingual and multi-regional hreflang tag sets are correctly configured, self-referencing, and fully reciprocal across all language variants.
SEO Agencies — include hreflang audits in your standard technical SEO review process. Export CSV reports for client deliverables without needing a paid platform subscription.
Web Developers — check your hreflang implementation immediately after deployment. Catch misconfigured tags before they affect rankings.
Site Owners and Webmasters — if you manage a multilingual website on WordPress, Shopify, Webflow, Squarespace, or any other CMS, use this extension to verify that your hreflang plugin or theme is generating correct tags.
Content Managers — quickly check whether international versions of a page are correctly linked and whether the expected language variants exist.
QA Engineers — validate hreflang tag correctness as part of an international SEO QA checklist.

🔍 WHAT HREFLANG ISSUES DOES IT DETECT?
Hreflang Checker Pro detects all of the following issues, which are defined in Google's official hreflang documentation and widely recognised in the SEO industry as common implementation errors:
ERRORS (Critical — must fix):
✗ Invalid ISO 639-1 language code (e.g. "english" instead of "en")
✗ Duplicate hreflang language code (same lang appears more than once)
✗ HTTP 4xx error on hreflang target URL (page not found or forbidden)
✗ HTTP 5xx error on hreflang target URL (server error)
✗ Network error / unreachable URL on hreflang target
WARNINGS (Best practice — should fix):
⚠ Missing self-referencing hreflang tag
⚠ Missing x-default hreflang tag
⚠ Relative URL used instead of absolute URL
⚠ Hreflang target redirects to a different URL (301/302)
⚠ No return link found on hreflang target page (missing reciprocal tag)
⚠ Hreflang tag is JavaScript-injected rather than server-rendered

🛠 HOW IT WORKS

Click the Hreflang Checker Pro icon in your Chrome toolbar while on any webpage.
The extension instantly reads all hreflang tags from the page's DOM and validates language codes, checks for self-references, x-default, relative URLs, and duplicates.
It then fetches each target URL in the background to check HTTP status codes and verify that each linked page contains a return link pointing back to the current page.
Results are displayed in a clean, sortable table with colour-coded status indicators.
The toolbar icon updates to reflect the overall audit status — green for clean, orange for warnings, red for errors.
Export your results to CSV for reporting and documentation.

No page reload required. Works on HTTP and HTTPS pages. Works on pages with 1 hreflang tag or pages with 150+ hreflang tags.

🔒 PRIVACY AND PERMISSIONS
Hreflang Checker Pro is a privacy-first tool. Here is exactly what it does and does not do:
WHAT WE DO:

Read the DOM of the currently active tab when you click the extension (activeTab permission)
Fetch hreflang target URLs from the background service worker to check HTTP status and return links — these are the same URLs that are publicly listed in the page's own hreflang tag set
Store your extension settings (on/off toggles and slider values) locally in Chrome's storage — this data never leaves your browser

WHAT WE DO NOT DO:

We do not collect, store, or transmit any data about you, your browsing history, or the pages you visit
We do not send any page content to any external server
We do not use analytics or tracking of any kind
We do not require an account, login, or email address
We do not monetise your data in any way

Permissions used:

activeTab — to read hreflang tags from the current page
scripting — to inject the content script that reads the page DOM
storage — to save your settings preferences locally
tabs — to identify the active tab
webNavigation — to reset the toolbar icon when you navigate to a new page
host_permissions (<all_urls>) — required so the background service worker can fetch hreflang target URLs to check HTTP status and return links

📊 COMPARISON WITH OTHER TOOLS
Many SEO platforms (Screaming Frog, Sitebulb, Ahrefs, SEMrush) include hreflang auditing as part of large site crawls — but they are expensive, require desktop software or subscriptions, and are not practical for quickly checking a single page during development, QA, or a client call.
Browser-based hreflang checkers exist as standalone websites where you paste a URL — but they require leaving the page you are auditing, do not show real-time results, and typically cannot check reciprocal links across the full tag set.
Hreflang Checker Pro gives you the depth of a professional audit tool in the convenience of a Chrome extension — free, instant, and always one click away.

⭐ TIPS FOR GETTING THE BEST RESULTS

For pages with large hreflang sets (50+ tags), allow a few seconds for all reciprocal link checks to complete. You can watch the progress bar and see results updating live.
If you see JS badges on your hreflang tags, investigate whether your CMS or framework is rendering hreflang server-side. Tags that are not in the raw HTML may be missed by Google.
Use the "Issues First" sort to immediately surface the rows that need attention on pages with many tags.
Use CSV export to document hreflang audits in client reports or track changes over time.
If return link checking is slow on a large international site, you can reduce the number of concurrent requests in Settings to avoid rate-limiting.
For sites using CDNs or geo-redirects, the HTTP status shown may reflect CDN-level responses rather than the origin server. Keep this in mind when interpreting 301 redirect flags.

🌍 IDEAL FOR AUDITING SITES ON ANY PLATFORM
Hreflang Checker Pro works on any website regardless of how it was built.