Internationalization Check: a beginner's guide
Hreflang, language, charset, and RTL support
Internationalization: how websites speak more than one language without breaking
Internationalization (often abbreviated i18n because there are 18 letters between the i and the n) is the practice of building a website that can be adapted to multiple languages, regions, currencies, date formats, and cultural conventions without rewriting the underlying code. The related practice, localization (l10n), is the actual process of adapting content for a specific market — translating the strings, formatting the prices, choosing the right images. A well-internationalized site can be localized for a new market in days. A badly-internationalized site requires a rewrite for every new language it wants to support.
You should care because most websites that try to go international fail in subtle ways that frustrate users and hurt SEO. The classic mistakes: using one URL for all languages and serving different content based on the visitor's IP (search engines hate this); using `?lang=fr` query parameters that don't get indexed properly; mixing date formats inconsistently; assuming all currencies have two decimal places (some have zero, like the Japanese yen); assuming all writing goes left to right (Arabic and Hebrew don't); embedding text in images that can't be translated. Each one is a small thing; together they make a site feel foreign in exactly the way you don't want.
The five things every internationalization check looks at:
`hreflang` tags. The standard way to tell search engines that two pages are translations of each other. Missing or broken `hreflang` is the single most common internationalization SEO problem.
URL structure. Each language version should have a stable, distinct URL — either subdirectories (`example.com/fr/page`), subdomains (`fr.example.com/page`), or country TLDs (`example.fr/page`). All three are valid; query parameters are not.
Language declaration. The HTML `<html lang="fr">` attribute tells browsers and screen readers which language the page is in.
Currency, date, and number formatting. A user in France expects `1 234,56 €`, not `$1,234.56`. A user in Japan expects `2025年4月8日`, not `4/8/2025`.
Right-to-left support. Sites targeting Arabic or Hebrew speakers need full RTL layout support — text alignment, navigation order, and even icon mirroring.
Three questions an internationalization check answers:
Is my multi-language site set up in a way that search engines can index correctly?
Are the locale-specific details (currency, dates, numbers) correct for each market?
For a new market launch, what specific changes do I need to make before going live?
The cost of skipping internationalization is silent failures in markets you thought you were serving — wrong currency, wrong date format, missing language tags, lost SEO. The fix is a one-time architectural pass plus a pre-launch checklist for each new market. The most useful technical reference is the Google Search guidance on `hreflang`.
The Internationalization Check endpoint, in plain language
In one sentence: Hreflang, language, charset, and RTL support
Checks internationalization setup including hreflang tags, language attributes, charset declaration, and RTL (right-to-left) support for multi-language websites.
Don't worry if some of the words above are still unfamiliar — there's a plain-language glossary at the bottom of this page, and most of the terms link to their own beginner guides if you want to learn more.
What is actually happening when you call it
Here's what's actually happening behind the scenes when you call this endpoint:
Analyzes the page for i18n configuration: hreflang tag presence, count, and proper x-default usage; HTML (HyperText Markup Language) lang attribute validity against BCP 47; Content-Language header consistency; charset declaration (UTF-8 verification); and RTL support via dir attributes and CSS (Cascading Style Sheets) rules. Detects language switcher UI elements (informational, not scored). Returns a score with specific recommendations and a confidence indicator reflecting result reliability.
If you're using an AI assistant through MCP, you don't need to understand any of the technical details — the assistant calls the tool and translates the result for you.
Why this specific tool matters
Let's skip the marketing fluff and answer the only question that actually matters: why should you, a real human with a real to-do list, care about the Internationalization Check tool? Here's the plain-English version, written the way you'd hear it from a friend who happens to do this for a living.
Incorrect hreflang tags cause search engines to show the wrong language version to users, losing international traffic. Missing or invalid lang attributes affect screen readers and translation tools. Proper i18n is essential for global reach.
Picture this in real life. Imagine an international SEO. Here's the situation they're walking into: Verify hreflang tags correctly map language/region variants to prevent ranking cannibalization. Without the right tool, that person would be stuck copy-pasting between five browser tabs, reading documentation written for engineers, and crossing their fingers that the answer they cobble together is correct. With the Internationalization Check tool, the same person gets a clear answer in seconds — no spreadsheets, no guessing, no waiting for someone on the infrastructure team to free up.
Three questions this tool answers in plain English. If any of these have ever crossed your mind, the Internationalization Check tool is built for you:
Does my website meet the legal requirements (accessibility, privacy, international standards)?
If a regulator audited my site tomorrow, what would they find?
Where are the gaps I should fix before they become an expensive problem?
You can either click the tool and get the answer yourself, or ask your AI assistant — connected through MCP (Model Context Protocol) — to ask the question for you and translate the answer into something you can paste into Slack.
Who gets the most out of this. Legal and compliance teams, accessibility officers, data-protection officers, and product managers shipping into regulated markets. If you see yourself in that list, this is one of the EdgeDNS tools you should bookmark today.
What happens if you skip this entirely. Skip it and you discover the violation when a regulator, a lawyer, or an angry customer finds it for you. That's why running this check — even once a month — is one of the cheapest forms of insurance you can give your domain.
Available on the developer plan. The technical details: `GET /v1/domain/i18n`.
When would I actually use this?
If you're still on the fence about whether the Internationalization Check tool belongs in your toolbox, this section is for you. Below you'll meet three real people — an international SEO, a localization manager, and a web developer — facing three real situations where this tool turns a stressful afternoon into a five-minute task. Read whichever story sounds closest to your week.
Story 1: International SEO Audit
Imagine you're an international SEO. Verify hreflang tags correctly map language/region variants to prevent ranking cannibalization.
Why it matters: Ensure the right language page ranks in each country's search results.
Story 2: Localization QA
Imagine you're a localization manager. Validate that translated pages have proper lang attributes and hreflang cross-references.
Why it matters: Confirm technical setup matches localization strategy.
Story 3: Accessibility Validation
Imagine you're a web developer. Check that the lang attribute is set correctly for screen readers and browser translation.
Why it matters: Improve accessibility for users relying on language detection.
Common situations across teams. Beyond the three stories above, here are the everyday workplace moments when people across the company reach for the Internationalization Check tool — or one of the tools right next to it in this category. If any of these are on your calendar this month, that's your sign:
Before launching into a new region (especially the EU, the UK, California, or Canada).
During a quarterly compliance review.
When a customer or partner sends you a security questionnaire.
In response to a complaint, audit notice, or legal threat.
If you can see yourself in even one of those bullets, the Internationalization Check tool will pay for itself the first time you use it.
Still not sure? Here's the easiest test in the world. Open Claude, ChatGPT, Gemini, or any other AI assistant connected to the EdgeDNS MCP server and ask, in your own words: "Is the Internationalization Check tool useful for my job?" The assistant will look at the tool, ask you a couple of follow-up questions about what you're trying to accomplish, and give you a straight answer in plain English. No commitment, no signup forms, no jargon.
The easiest way: just ask your AI assistant
If you've connected the EdgeDNS MCP server to Claude, ChatGPT, Gemini, Cursor, or any other AI assistant, you don't need to write any code. Just ask in plain English:
"Use the Internationalization Check tool to check example.com and explain anything that looks wrong in plain language."
The AI will figure out which tool to call, fill in the right parameters, run it, and then explain the result back to you. No copy-pasting between tabs. No reading raw JSON. No memorizing endpoint names.
MCP (Model Context Protocol) access is free on every plan, including the free tier. One API key works for both REST and AI — you do not have to choose.
The technical way: call it from code
If you're a developer and want to call the endpoint from a script or your own application, here's the simplest possible example. Replace the placeholder API key with the real one from your dashboard.
# Replace edns_live_YOUR_KEY with your real API key from the dashboard
curl -H "Authorization: Bearer edns_live_YOUR_KEY" \
"https://api.edgedns.dev/v1/domain/i18n?domain=example.com"What you need to provide
There's just one piece of information you need to provide. The table below explains exactly what it is and what a real value looks like.
| Field | Type | Required? | What it means | Example |
|---|---|---|---|---|
domain | string | Yes | The domain to check internationalization for | example.com |
What you get back
When you call this tool, you'll get back a JSON object with the fields below. If you're talking to it through an AI assistant, the assistant reads these for you and explains them in plain language — you don't need to memorize them.
| Field | Type | What you'll see in it |
|---|---|---|
domain | string | The checked domain |
hreflang | object | Hreflang tags: count, languages, x-default, issues |
language | object | HTML (HyperText Markup Language) lang attribute, validity, Content-Language header |
charset | object | Charset declaration and UTF-8 verification |
rtlSupport | object | RTL detection, dir attribute, CSS (Cascading Style Sheets) RTL support |
languageSwitcher | object | Language switcher UI detection (informational) |
score | number | Internationalization score 0-100 |
grade | string | Letter grade A-F |
gradeDescription | string | Human-readable grade description (e.g., "Good - adequate with room for improvement") |
recommendations | array | Specific i18n fixes to implement |
confidence | object | Result confidence indicator: level (high/medium/low) and limitations list |
Words you might be wondering about
If any words on this page felt like jargon, here's a plain-language version. Click any linked term to read a full beginner-friendly guide.
HTML (HyperText Markup Language) — The basic language web pages are written in. The tags you see in the source code (<h1>, <p>, <a>) are HTML.
CSS (Cascading Style Sheets) — The language used to control how a web page looks — colors, fonts, spacing, layout. HTML says what content is on the page; CSS says how it looks.
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