---
title: "Translate XLIFF and CAT tool files"
description: "Pre-translate XLIFF 1.2 and 2.0, Trados SDLXLIFF, memoQ MQXLIFF and Phrase MXLIFF files up to 12 MB. Ids, tags and locked segments stay, and results are marked as drafts."
canonical: "https://ai-glot.com/docs/formats/xliff-and-cat-tools"
updated: "2026-10-12"
---

# Translate XLIFF and CAT tool files

XLIFF files (`.xlf` and `.xliff`, versions 1.2 and 2.0) and the bilingual files of the main translation tools, Trados `.sdlxliff`, memoQ `.mqxliff` and Phrase `.mxliff`, are accepted up to **12 MB**. The file keeps its structure, ids and segmentation, and only the targets are filled in. The use case is pre-translation: your reviewer edits and confirms instead of typing.

> **Tip: Try it free**
>
> Drop a file of up to 2 MB on the free translators for [XLIFF](https://ai-glot.com/file-formats/xliff-translation) or [Trados, memoQ and Phrase files](https://ai-glot.com/file-formats/sdlxliff-translation) to try them with no account, five files a day. The app, the API and the CLI take files up to 12 MB.

## What is translated, and what is left alone

|                       | Translated                           | Left as it was                                                        |
| --------------------- | ------------------------------------ | --------------------------------------------------------------------- |
| XLIFF 1.2 and 2.0     | Empty targets, and others if you ask | Unit ids, inline tags (`g`, `x`, `ph`, `pc`, `mrk`), state attributes |
| Trados, memoQ, Phrase | Unlocked segments                    | Locked segments, segmentation, ids, the tool's own markup             |

In XLIFF 2.0 the first segment of each unit is the one translated. Existing translations are kept unless you ask to redo them, and the plan reports how many units it will fill.

## Draft status

Everything AI Glot writes into a Trados, memoQ or Phrase file is marked as an **unconfirmed machine draft**, never as confirmed work: Draft with machine origin in Trados, PartiallyEdited in memoQ, unconfirmed in Phrase. The translator confirms in the tool.

## What you can ask

**Pre-translate the empty targets**

The standard use: fill what is empty, keep what exists.

Pre-translate the empty targets into French. Keep existing translations as they are.

**Protect placeholders**

Keeps variables in text safe, on top of the inline tags that are always protected.

Translate the empty targets into German. Keep placeholders such as \{count} and %s unchanged.

**Redo the weak matches**

Overwrites existing targets only when you say so.

Redo the targets that are not yet approved in Spanish, and leave approved units alone.

**A Trados project**

Fills unlocked segments and leaves repetitions and approved text.

Pre-translate the empty segments into Italian. Do not touch locked segments or segments that already have a translation.

**Only the changed units**

For plain XLIFF: returns just the units that were written.

Translate the empty targets into Portuguese and return only the units you changed.

## Good to know

- **One target language per upload.** A bilingual file has one target language. If you ask for two, the plan translates one and says so. Run the file once per language: your [glossary](/docs/platform/glossaries) carries over.
- **Output filter.** Available for plain XLIFF only. A Trados, memoQ or Phrase file always comes back whole, because the tool maps every unit back by its id.
- **Ask for the file's own target language.** Name the language the file is set up for. If you ask for a different one, the plan follows your instruction and notes the difference.
- **Locked segments are never written** in Trados, memoQ or Phrase files.
- **Phrase tags** such as `{1}` and `{2>text<2}` are protected and kept in the translated segment.
- **Not certified.** AI Glot checked the output against real exports, but has not certified an import into Trados, memoQ or Phrase themselves. Open a small file in your tool first.
- **Recognition.** The tool is recognised from the file itself, whatever the extension, including an XLIFF 1.2 file produced by one of those tools.
- **Ceiling.** 12 MB.

## Related

- [gettext PO](/docs/formats/gettext-po) and [.NET and Qt](/docs/formats/dotnet-and-qt) for other bilingual formats.
- [All file formats](/docs/formats)