What is Document Translation?

Document Translation is a cloud-based machine translation feature of the Azure AI Translator service. You can translate multiple and complex documents across all supported languages and dialects while preserving original document structure and data format. The Document translation API supports two translation processes:

  • Asynchronous batch translation supports the processing of multiple documents and large files. The batch translation process requires an Azure Blob storage account with storage containers for your source and translated documents.

  • Synchronous single file supports the processing of single file translations. The file translation process doesn't require an Azure Blob storage account. The final response contains the translated document and is returned directly to the calling client.

Asynchronous batch translation

Use asynchronous document processing to translate multiple documents and large files.

Batch key features

Feature Description
Translate large files Translate whole documents asynchronously.
Translate numerous files Translate multiple files across all supported languages and dialects while preserving document structure and data format.
Preserve source file presentation Translate files while preserving the original layout and format.
Apply custom glossaries Translate documents using custom glossaries.
Automatically detect document language Let the Document Translation service determine the language of the document.
Translate documents with content in multiple languages Use the autodetect feature to translate documents with content in multiple languages into your target language.

Batch development options

You can add Document Translation to your applications using the REST API or a client-library SDK:

  • The REST API. is a language agnostic interface that enables you to create HTTP requests and authorization headers to translate documents.

  • The client-library SDKs are language-specific classes, objects, methods, and code that you can quickly use by adding a reference in your project. Currently Document Translation has programming language support for C#/.NET and Python.

Batch supported document formats

The Get supported document formats method returns a list of document formats supported by the Document Translation service. The list includes the common file extension, and the content-type if using the upload API.

File type File extension Description
Adobe PDF pdf Portable document file format. Document Translation uses optical character recognition (OCR) technology to extract and translate text in scanned PDF document while retaining the original layout.
Comma-Separated Values csv A comma-delimited raw-data file used by spreadsheet programs.
HTML html, htm Hyper Text Markup Language.
Localization Interchange File Format xlf A parallel document format, export of Translation Memory systems. The languages used are defined inside the file.
Markdown markdown, mdown, mkdn, md, mkd, mdwn, mdtxt, mdtext, rmd A lightweight markup language for creating formatted text.
M​HTML mthml, mht A web page archive format used to combine HTML code and its companion resources.
Microsoft Excel xls, xlsx A spreadsheet file for data analysis and documentation.
Microsoft Outlook msg An email message created or saved within Microsoft Outlook.
Microsoft PowerPoint ppt, pptx A presentation file used to display content in a slideshow format.
Microsoft Word doc, docx A text document file.
OpenDocument Text odt An open-source text document file.
OpenDocument Presentation odp An open-source presentation file.
OpenDocument Spreadsheet ods An open-source spreadsheet file.
Rich Text Format rtf A text document containing formatting.
Tab Separated Values/TAB tsv/tab A tab-delimited raw-data file used by spreadsheet programs.
Text txt An unformatted text document.

Batch Legacy file types

Source file types are preserved during the document translation with the following exceptions:

Source file extension Translated file extension
.doc, .odt, .rtf, .docx
.xls, .ods .xlsx
.ppt, .odp .pptx

Batch supported glossary formats

Document Translation supports the following glossary file types:

File type File extension Description
Comma-Separated Values csv A comma-delimited raw-data file used by spreadsheet programs.
Localization Interchange File Format xlf , xliff A parallel document format, export of Translation Memory systems The languages used are defined inside the file.
Tab-Separated Values/TAB tsv, tab A tab-delimited raw-data file used by spreadsheet programs.

Synchronous translation

Use synchronous translation processing to send a document as part of the HTTP request body and receive the translated document in the HTTP response.

Synchronous translation key features

Feature Description
Translate single-page files The synchronous request accepts only a single document as input.
Preserve source file presentation Translate files while preserving the original layout and format.
Apply custom translation Translate documents using general models.
Apply custom glossaries Translate documents using custom glossaries.
Single language translation Translate to and from one supported language.
Automatically detect document language Let the Document Translation service determine the language of the document.
Apply custom glossaries Translate a document using a custom glossary.

Synchronous supported document formats

File type File extension Content type Description
Plain Text .txt text/plain An unformatted text document.
Tab Separated Values .txv
.tab
text/tab-separated-values A text file format that uses tabs to separate values and newlines to separate records.
Comma Separated Values .csv text/csv A text file format that uses commas as a delimiter between values.
HyperText Markup Language .html
.htm
text/html HTML is a standard markup language used to structure web pages and content.
M​HTML .mthml
.mht
message/rfc822
@application/x-mimearchive
@multipart/related
A web page archive file format.
Microsoft PowerPoint .pptx application/vnd.openxmlformats-officedocument.presentationml.presentation An XML-based file format used for PowerPoint slideshow presentations.
Microsoft Excel .xlsx application/vnd.openxmlformats-officedocument.spreadsheetml.sheet An XML-based file format used for Excel spreadsheets.
Microsoft Word .docx application/vnd.openxmlformats-officedocument.wordprocessingml.document An XML-based file format used for Word documents.
Microsoft Outlook .msg application/vnd.ms-outlook A file format used for stored Outlook mail message objects.
Xml Localization Interchange .xlf
.xliff
application/xliff+xml A standardized XML-based file format widely used in translation and localization software processing.

Synchronous supported glossary formats

Document Translation supports the following glossary file types:

File type File extension Description
Comma-Separated Values csv A comma-delimited raw-data file used by spreadsheet programs.
XmlLocalizationInterchange xlf , xliff An XML-based format designed to standardize how data is passed during the localization process.
TabSeparatedValues tsv, tab A tab-delimited raw-data file used by spreadsheet programs.

Document Translation Request limits

For detailed information regarding Azure AI Translator Service request limits, see Document Translation request limits.

Next steps

In our quickstart, you learn how to rapidly get started using Document Translation. To begin, you need an active Azure account. If you don't have one, you can create a Trial.