Translation delivery networks (TDNs) are a new and powerful way to launch multilingual websites. These services work by intercepting webpages as they are served to visitors, and “redraw” the pages by replacing the source texts with translations, all while preserving the original look and feel of the website. Best of all, these services don’t require you to install any software on your web server.

Smartling, headquartered in the Chelsea district of New York City, has pioneered the development of TDNs, and offers a turnkey website translation service that is used by leading Internet brands, including Foursquare, Vimeo, and Uber. Similar companies and services include Dakwak and GTranslate.

TDNs are whats called a reverse proxy , this is a web server or cluster of web servers that sit between the web visitor and the source web server. When the visitor requests a page or item that is not already cached on the proxy server, it loads that page or URL from the web server, and then examines the page to extract human readable texts. For each human readable text it finds in the page, it does the following.

1. Checks its local cache of recently translations, to see if it has a translation for the text in local memory. If so, it uses this (it does this so pages are served as quickly as possible because reading from memory is ten times faster than reading from a disk drive).
2. It checks its local database (on disk) to see if it has a translation for the text. If so, it uses this, and also stores a copy in memory based cache (so subsequent lookups are faster).
3. If it didn’t find a translation on disk, it calls out over the network to one or more cloud based translation services, such as Google Translate, Gengo, One Hour Translation, and so on. These translations are, in turn, stored and cached for future use.
4. Replaces the original text with the best available human or machine translation. Repeat steps 1 through 4 until the page is translated, then serve the page to the visitor. This all happens within a fraction of a second if the system is designed correctly.

The precise details of how the translations are stored and requested vary from vendor to vendor, but that’s the basic process used to build a TDN. The beauty of this approach is that it requires no software changes on the web server. The site owner simply creates subdomains, like es.company.com for Spanish, and points them to the translation proxy which, in turn calls up to http://www.company.com when it needs to request something. In addition to make translation much easier, TDNs can be integrated with content delivery networks to boost website performance, reduce server load, and protect against denial of service attacks.

In fact, Cloudflare does just this, and offers Smartling as an easily activated option within their CDN service. You simply check a box to activate Smartling and select your languages, and they take care of everything else.