WPML

What Is WPML?

WPML, short for the WordPress Multilingual Plugin, is a premium plugin that turns a standard WordPress site into a multilingual one, letting a single installation publish content in many languages with a front-end language switcher and proper SEO signals. It is one of the most established and widely used translation solutions for WordPress, with a long history in the ecosystem and a large base of professional and enterprise sites that rely on it to reach international audiences.

WPML was first released in 2007 and is developed by OnTheGoSystems. Unlike many popular WordPress plugins, it has always been a paid, premium product rather than a freemium one, distributed through its own site rather than the free WordPress plugin directory. That commercial model reflects its positioning as a professional-grade solution for businesses that take multilingual publishing seriously, with dedicated support, compatibility programs for themes and plugins, and integrations with professional translation services.

It is important to be clear about what WPML is and is not. It is a server-side WordPress plugin, PHP code installed into a self-hosted WordPress site, that manages translated versions of posts, pages, taxonomies, menus, and strings. It is not a hosted translation service that you embed from another domain, and it is not a browser extension or an automatic machine-translation overlay that visitors toggle in their browser. WPML stores genuine translated content in the WordPress database and serves the appropriate language version from the server based on the requested URL.

Because WPML manages language URLs, injects hreflang annotations, renders a language switcher, and registers internal markers prefixed with icl_ and wpml, it leaves recognizable fingerprints that both a human inspector and an automated server-side scanner like StackOptic can detect. The most universal of these signals, the hreflang link tags, are part of WPML's core SEO function and are present on virtually every WPML site.

A brief note on naming helps explain the fingerprints. WPML's codebase originated under the name "ICL" (the project's original branding), and that prefix persists throughout the plugin's classes, scripts, cookies, and option names to this day. So when you see both wpml and icl markers on a site, you are seeing two generations of the same product's naming, which together make WPML one of the more identifiable premium WordPress plugins.

How WPML Works

WPML layers a translation-management system on top of WordPress's content model. After installation, you define a default language and one or more secondary languages. For each piece of content, a post, page, custom post type, category, tag, or menu, WPML lets you create and link translated versions, keeping them connected as a single logical item across languages. Editors can translate content manually, assign it to translators through a built-in Translation Management workflow, or send it to integrated professional and machine-translation services.

Beyond post content, WPML translates the many smaller pieces of text that make up a site. Its String Translation component captures interface strings, widget text, theme and plugin labels, and other hard-coded phrases so that the entire experience, not just the articles, appears in the visitor's language. A companion component handles translating theme and plugin output that is not stored as normal posts.

URL structure is central to how WPML serves languages. It supports three common strategies: a language directory in the path (for example /fr/ or /de/), a language subdomain (fr.example.com), or an entirely separate domain per language (example.fr). Whichever is chosen, WPML routes the request to the correct translated content and renders that language's version on the server.

Crucially for search visibility, WPML automatically adds hreflang annotations that tell search engines which URL serves which language and region. This is the single most important SEO function of the plugin and the reason multilingual sites use a dedicated tool rather than ad-hoc duplication. To understand why this matters so much, see our explainer on what is international SEO and hreflang; WPML exists in large part to implement those best practices correctly and at scale.

On the front end, WPML renders a language switcher, a menu, dropdown, or list of flags and language names, that lets visitors move between language versions. It also commonly sets a cookie to remember a visitor's language preference. The switcher markup and the language cookie are both recognizable signals, as discussed below.

A useful way to picture the workflow is to follow one article through the system. An editor writes a post in English (the default language), then opens WPML's translation editor and either translates it into French and German themselves or dispatches it to translators. WPML creates linked French and German versions, places them at /fr/ and /de/ URLs, adds reciprocal hreflang tags connecting all three, and surfaces all three in the language switcher. A French-speaking visitor lands on the French URL, sees the French version, the French interface strings, and a switcher offering English and German, while search engines receive clean hreflang signals pointing each audience to the right page. This coordinated handling of content, interface, URLs, and SEO is the essence of WPML.

How to Tell if a Website Uses WPML

WPML leaves several dependable fingerprints. Because StackOptic analyzes a URL from the server side, it inspects the same signals you can check manually with View Source, DevTools, or a detection extension. Since WPML only runs on WordPress, confirming WordPress itself (via /wp-content/ paths, a wp-json endpoint, or a WordPress generator tag) is a sensible first step.

Hreflang link tags. The most universal signal is a set of <link rel="alternate" hreflang="..."> tags in the page <head>, one per language, pointing at the corresponding translated URLs. WPML generates these automatically, so they appear on essentially every WPML site. While other plugins can also emit hreflang, their presence on a WordPress site is a strong starting indicator.

ICL/WPML asset paths. WPML's scripts and styles load from the plugin directory, with paths containing /wp-content/plugins/sitepress-multilingual-cms/ (the core plugin's internal name is "sitepress") and related addon directories such as wpml-string-translation. These paths are a specific, reliable tell.

icl_ and wpml markers in markup and scripts. Because the codebase originated as "ICL," you will find icl-prefixed identifiers in the HTML and JavaScript, for example a JavaScript object or settings under names like icl_vars, body or container classes referencing the language, and switcher markup with classes such as wpml-ls (WPML Language Switcher), wpml-ls-item, and wpml-ls-link. The wpml-ls-* classes on the language switcher are an especially clean signal.

The language switcher itself. A visible switcher listing multiple languages, often with flags or language names, rendered with wpml-ls markup, both indicates a multilingual site and points specifically to WPML.

Language cookie. WPML commonly sets a cookie to remember the selected language (historically named with an _icl_ style prefix). Spotting such a cookie in DevTools corroborates the plugin.

Language URL structure. URLs organized as /fr/, /de/, language subdomains, or per-language domains, especially when paired with the signals above, reinforce that a structured multilingual plugin is in use.

Here is how to verify each signal yourself:

Method	What to do	What WPML reveals
View Source	"View Page Source" on the homepage	hreflang link tags, wpml-ls switcher markup, icl/wpml references
Browser DevTools	Inspect the switcher element, Network tab, and the cookies panel	/plugins/sitepress-multilingual-cms/ requests, wpml-ls-* classes, the language cookie
curl	`curl -s https://example.com	grep -iE "hreflang
Wappalyzer	Run the extension on the live page	Identifies "WPML" under translation / WordPress plugins
BuiltWith	Look up the domain	Current and historical WPML detection plus hosting profile

A fast terminal check is curl -s https://example.com | grep -i "sitepress-multilingual-cms", followed by curl -s https://example.com | grep -i "wpml-ls". A match on either is strong evidence of WPML. For the wider methodology, see how to find out what technology a website uses and, since WPML is a plugin, how to identify a WordPress theme and plugins.

One nuance worth understanding is distinguishing WPML from its main competitor, Polylang, since both produce hreflang tags and language switchers. The deciding signals are the plugin paths and class prefixes: WPML uses the sitepress-multilingual-cms directory and icl_/wpml-ls markers, whereas Polylang uses a /plugins/polylang/ path and lang_* / polylang markers. Because the hreflang annotation alone is not unique to WPML, the strongest approach combines several signals, the asset path, the switcher classes, and the language cookie, which an automated server-side scan can evaluate together for a confident verdict even on a customized theme.

Key Features

• Full content translation. Translate posts, pages, custom post types, taxonomies, and menus while keeping language versions linked as one item.
• String Translation. Translate interface text, widget content, and theme/plugin strings so the entire site, not just articles, is localized.
• Flexible language URLs. Choose language directories, subdomains, or separate domains per language to match SEO and branding needs.
• Automatic hreflang. Generates correct hreflang annotations so search engines serve the right language and region to each audience.
• Translation Management. Assign content to translators, track progress, and connect to professional and machine-translation services.
• Language switcher. A configurable front-end switcher (menu, dropdown, or widget) lets visitors change languages easily.
• Compatibility focus. A long-running program for compatibility with popular themes, page builders, and major plugins, including ecommerce.
• Multilingual ecommerce. Works with WooCommerce (via a companion component) to translate products, categories, and checkout.

Pros and Cons

Pros

• Mature, full-featured, and well-supported, with a strong compatibility track record across themes and plugins.
• Implements hreflang and language URLs correctly, which is essential for international SEO.
• Flexible translation workflows, from manual editing to professional translation services.
• Handles the hard parts, strings, menus, taxonomies, and ecommerce, not just post bodies.

Cons

• Premium-only with no free tier, and licenses renew annually.
• Can add database and front-end overhead on large sites, so performance tuning matters.
• More complex to configure than a single-language site, with a real learning curve.
• As a WordPress-only plugin, it is not usable on non-WordPress platforms.

WPML vs Alternatives

WPML competes with other WordPress multilingual plugins and with hosted translation-layer services. The table below highlights where it fits.

Solution	Type	Translation model	Best for
WPML	WordPress plugin (premium)	Human + integrated machine translation	Professional and enterprise multilingual sites
Polylang	WordPress plugin (freemium)	Manual, with a paid Pro tier	Sites wanting a free or lower-cost starting point
TranslatePress	WordPress plugin (freemium)	Front-end visual translation	Visual, see-as-you-translate editing
Weglot	Hosted SaaS layer	Automatic + editable, served via proxy	Fast setup with a translation layer over any platform
Multisite + manual	Core WordPress	Separate site per language	Teams wanting full separation and bespoke control

If a site turns out to use a different multilingual tool, the same inspection techniques identify it, the hreflang tags will be present either way, while the plugin path and class prefix reveal the specific plugin. You can also compare WPML with a different category of WordPress plugin such as Yoast SEO to see how SEO and translation plugins each fingerprint a site.

Use Cases

WPML is the natural choice when a WordPress site must serve audiences in multiple languages with proper SEO. International businesses use it to publish marketing sites in the languages of each market they sell into. Ecommerce stores use it (with WooCommerce) to localize products, categories, and checkout so shoppers buy in their own language and currency context.

It also fits multinational organizations and institutions publishing official content in several languages, travel and hospitality brands serving global visitors, and content publishers expanding into new linguistic markets. Because WPML coordinates content, interface strings, URLs, and hreflang together, it is especially valuable where getting international SEO right, so each market's audience lands on the correct localized page, directly affects organic traffic and revenue.

From a competitive-intelligence and lead-qualification perspective, detecting WPML on a site is a rich signal. It indicates a self-hosted WordPress site that operates internationally and has invested in a premium, professional translation solution, often a sign of a business with cross-border ambitions and budget. For vendors selling localization services, international marketing, or global ecommerce tooling, that is a high-value qualifying signal. Identifying the multilingual stack across many prospects at once, rather than inspecting each site by hand, is exactly the kind of insight technology detection surfaces, as discussed in what is technographics: using tech stack data to qualify leads.

Frequently Asked Questions

Is WPML free?

No. WPML is a premium, paid plugin distributed by OnTheGoSystems through its own website rather than the free WordPress plugin directory, and it has no free tier. Licenses are sold in annual subscriptions across several levels (such as Multilingual Blog, Multilingual CMS, and Multilingual Agency), with higher tiers unlocking String Translation, Translation Management, ecommerce support, and use across more sites. The lack of a free edition reflects its positioning as a professional-grade solution with dedicated support.

How can I tell if a website uses WPML rather than another translation plugin?

Look beyond the hreflang tags, which several plugins emit, to WPML-specific markers. In the page source and Network tab, check for asset paths containing /wp-content/plugins/sitepress-multilingual-cms/, language-switcher markup using wpml-ls classes, and icl_-prefixed JavaScript or cookies. Polylang, the main alternative, instead uses a /plugins/polylang/ path and polylang/lang_ markers. The combination of the sitepress path and wpml-ls classes is the clearest confirmation of WPML specifically.

Does WPML do automatic machine translation?

WPML supports both human and machine translation. Editors can translate content manually, assign it to translators through its Translation Management workflow, or use integrated automatic translation that produces machine translations which humans can then review and refine. This flexibility lets teams choose speed or accuracy per piece of content. Importantly, WPML stores the resulting translations as real content in the site's database and serves them from the server, rather than translating pages on the fly in the visitor's browser.

Why does WPML use both "wpml" and "icl" in its code?

The plugin originated under the project name "ICL," and that prefix remains throughout its internal classes, scripts, option names, and cookies even though the product is marketed as WPML. The core plugin directory is also named sitepress-multilingual-cms for historical reasons. As a result, a WPML site typically shows a mix of wpml, icl, and sitepress identifiers, and seeing these together is a reliable way to confirm the plugin.

Does WPML help or hurt SEO?

Used correctly, WPML helps international SEO. Its core value is generating proper hreflang annotations and clean per-language URLs so search engines serve each audience the right localized page, avoiding duplicate-content confusion across languages. As with any plugin, performance matters: large multilingual sites should use caching and good hosting so the added content does not slow pages. The plugin also works alongside SEO plugins like Yoast so titles, meta descriptions, and sitemaps remain optimized in every language.

Want to detect WPML and the full stack behind any site in seconds? Try StackOptic at https://stackoptic.com.