Most of the API endpoints require an authanticated TranslationHUB user. You don't need to create any API key, once you're registered to our site, you are ready to use our API with your email and password.
After you're registered to TranslationHUB, you can obtain an authentication token by using /auth/login endpoint ( with your email and password ) . Authentication tokens are valid for 24 hours and can be used for all subsequent calls. You don't need to create a new token for every api call. In fact, we prefer you don't do that :)
Our Sandbox api ( testing free with fake data ) requires same authentication with production api. However Sandbox and production api calls are made from different subdomains. (sandbox.translationhub.com and api.translationhub.com)
You can create your account at http://translationhub.com/auth/register