Methods, systems, and apparatus, including computer program products, for translation of markup language documents with display replacement. In some implementations, a method includes displaying a markup language document in an original language by rendering an internal representation of the document, sending a data structure containing the texts from the text nodes of the internal representation, as distinct data entities, to a translation service, replacing the texts with translated texts received from the translation service resulting in a translated representation, and displaying a first translation of the document by rendering the translated representation. In some implementations, partial, incremental translation is performed. In some implementations, a method includes receiving a notification that a phrase in a markup language document has been selected, requesting translation of the text of the selected phrase, and then displaying a received translation in a user interface.