IDML vs INDD: Which File Format Should You Send Your Translation Agency?
Key Takeaways
- IDML is the correct format to send to a translation agency — not INDD.
- IDML (InDesign Markup Language) is an open XML-based format that exposes the text content of an InDesign file in a structure compatible with professional translation memory tools.
- INDD is a binary format that cannot be processed by translation memory software without conversion.
- IDML files are significantly smaller than INDD files because they do not carry linked images and graphics.
- The INDD file and all linked assets should be retained internally and used at the DTP stage, when the translated IDML is reimported into the original InDesign document.
If you are preparing an InDesign document for translation, one of the first practical questions is which file format to send. Adobe InDesign saves files in two main formats — INDD and IDML — and understanding the difference between them matters for how efficiently your translation project can be handled.
What is an INDD file?
INDD is Adobe InDesign's native binary file format. It stores everything in the document: layout structure, text, formatting, layer information, links to external graphics files, document history, and InDesign-specific metadata.
INDD files are the working files for InDesign projects. They open and save quickly in InDesign, preserve every design feature the software supports, and are the format designers work with day to day.
However, INDD is a proprietary binary format. It cannot be read or processed by translation memory software without first being converted to an open format. Sending a raw INDD file to a translation agency means they need to do additional conversion work before translation can begin — or, if they do not have access to InDesign, they cannot process the file at all.
INDD files also carry all linked graphics and metadata, which makes them large — often much larger than the actual text content warrants.
What is an IDML file?
IDML stands for InDesign Markup Language. It is an open-format, XML-based representation of an InDesign document that exposes the text content of the file in plain text through XML tags and coding.
Unlike INDD, IDML is not a binary format — it is a structured text file that can be read and processed by professional translation memory tools such as MemoQ. When a translation agency imports an IDML file into MemoQ, the software extracts all translatable text segments, preserves the formatting tags associated with each segment, and presents the content to translators in a structured interface. Once translation is complete, MemoQ exports the translated IDML file with all formatting tags intact, ready to be reimported into InDesign.
IDML files are also significantly smaller than their INDD equivalents, because they do not include linked images or graphics — only the document structure and text content. This makes them faster to share and easier to manage across a translation project.
How to export IDML from InDesign
Exporting an IDML file from InDesign is straightforward:
- Open the INDD file in Adobe InDesign
- Go to File > Export
- In the Format dropdown, select InDesign Markup (IDML)
- Name the file and save
The exported IDML file is what you send to your translation agency. Keep the original INDD file and all linked assets — they are needed at the DTP stage when the translated IDML is reimported.
Why not just send the INDD file?
Some clients send the raw INDD file to their translation agency on the assumption that the agency can handle the conversion. A professional agency with InDesign access can do this — but it adds a step, and it means sharing a much larger file containing all your linked assets and document history.
More importantly, sending INDD does not guarantee that the agency will handle the file correctly. If the agency does not use professional translation memory software and instead copies text out of the InDesign file manually, the efficiency and consistency benefits of IDML are lost entirely — along with the cost savings that come from translation memory matching across the document.
Exporting IDML yourself before sending is a ten-second step that puts the project on the right footing from the start.
What about INX files?
INX (InDesign Interchange) was an earlier XML-based exchange format used by Adobe InDesign CS4 and earlier. IDML replaced INX from InDesign CS5 onwards. If you are working with a very old InDesign file, you may encounter INX — but for any InDesign version from CS5 onwards (which covers virtually all current projects), IDML is the correct export format.
What about packaging the InDesign file?
InDesign's Package function collects the INDD file together with all linked graphics, fonts, and assets into a single folder. Packaging is useful when handing a project to a designer or printer, but it is not the format to send to a translation agency.
A translation agency working with IDML and MemoQ does not need the linked graphics to complete the translation — only the text content in the IDML file. The packaged INDD with all assets is needed later, at the DTP stage, when the translated IDML is reimported and the layout is adjusted.
If your project includes text embedded within linked graphics — text that is part of an image rather than a separate InDesign text frame — you will need to share those specific graphic files separately so they can be localised alongside the main IDML translation.
The complete file handover: what to send
When briefing your translation agency on an InDesign project, send:
- The IDML export of the InDesign file
- Any linked graphics that contain embedded text (clearly flagged)
- A project brief noting the target languages, required deliverable format, and any terminology preferences or brand glossary
Keep the original INDD file and all linked assets ready for the DTP stage, when the translated IDML file is returned and reimported into your original InDesign document.
Global LTS works with IDML files using MemoQ for all InDesign translation projects, and our in-house multilingual DTP team handles the reimport and layout adjustment through to print-ready delivery. Contact us to discuss your project.
For related reading, see our full guide on how to translate an Adobe InDesign file and our overview of multilingual DTP services, or visit our InDesign translation services page.
