15. A non-transitory computer-readable storage media having instructions stored thereupon that are executable by one or more processors and which, when executed, cause the one or more processors to: receive a request from a computing device for a content item; determine that the content item is displayed at a rendered location on a display associated with the computing device; select a first machine translation service and a second machine translation service for translating the content item from a first language to a second language, the first machine translation service configured to generate a translation of the content item at a first quality level and the second machine translation service configured to generate a translation of the content item at a second quality level; transmit a request for a first translation to the first machine translation service to translate the content item from the first language to the second language; transmit a request for a second translation to the second machine translation service to translate the content item from the first language to the second language; receive the first translation of the content item from the first machine translation service; receive the second translation of the content item from the second machine translation service; provide the first translation of the content item to the computing device for presentation of the first translation at the rendered location on the display associated with the computing device; and provide the second translation of the content item to the computing device for presentation of the second translation of the content item at the rendered location on the display and in place of the first translation.
15. A non-transitory computer-readable storage media having instructions stored thereupon that are executable by one or more processors and which, when executed, cause the one or more processors to: receive a request from a computing device for a content item; determine that the content item is displayed at a rendered location on a display associated with the computing device; select a first machine translation service and a second machine translation service for translating the content item from a first language to a second language, the first machine translation service configured to generate a translation of the content item at a first quality level and the second machine translation service configured to generate a translation of the content item at a second quality level; transmit a request for a first translation to the first machine translation service to translate the content item from the first language to the second language; transmit a request for a second translation to the second machine translation service to translate the content item from the first language to the second language; receive the first translation of the content item from the first machine translation service; receive the second translation of the content item from the second machine translation service; provide the first translation of the content item to the computing device for presentation of the first translation at the rendered location on the display associated with the computing device; and provide the second translation of the content item to the computing device for presentation of the second translation of the content item at the rendered location on the display and in place of the first translation. 19. The non-transitory computer-readable storage media of claim 15 , wherein the first machine translation service or the second machine translation service is selected based upon an estimated difficulty of translating the content item.