A single SDLXLIFF file
Upload the SDLXLIFF file to a project with the same language pair. Smartcat reads the segments, and the file downloads again as SDLXLIFF.
Uploaded as it is
.sdlxliff
SDLXLIFF translator: open, translate and convert SDLXLIFF files online
Smartcat is an online SDLXLIFF translator for translators and agencies who get files from clients on Trados Studio. Open an SDLXLIFF file or project package in the browser, translate it with AI, translation memory and glossary, and download the SDLXLIFF in its original format, or export a bilingual Word file for review.
Translate any file. In seconds.
Images, docs, video, audio, courses — pick a format and drop your file.
Drop documents here
or browse files · Supports .docx, .pdf, .pptx, .xlsx and more
More than 80 of the world’s largest companies have chosen Smartcat
What is an SDLXLIFF file?
An SDLXLIFF file (.sdlxliff) is the bilingual XML file that RWS Trados Studio, formerly SDL Trados Studio, creates when it prepares a document for translation. It follows the XLIFF 1.2 standard plus Trados markup: each segment holds the source text, the translation, inline tags for formatting, and metadata such as segment status and match origin. It can also carry the original document, embedded as an encoded ZIP.
XLIFF 1.2 has been an OASIS Standard since 1 February 2008. Its specification lets tools add their own elements through XML namespaces, which is where Trados markup lives, and marks each segment with <mrk mtype="seg"> inside <seg-source>.
An SDLXLIFF translator opens that file, shows source and target side by side, and writes the translation back without touching the structure. Smartcat does this in the browser, so translators and agencies can take SDLXLIFF files from clients without installing a desktop CAT tool.
92%
of AI-translated words need no edit
92% of words translated by Smartcat AI are accepted without a single human edit.
280+
languages
Translate one SDLXLIFF file into 280+ languages, including right-to-left languages, in a single project.
80+
file formats
SDLXLIFF sits next to MQXLIFF, XLIFF, TTX, Office and design files in the same project and translation memory.
Why is an SDLXLIFF file hard to open outside its desktop tool?
Because only a CAT tool reads it safely. An SDLXLIFF file opens in any text editor, but the text sits between XML elements, tags and Trados metadata. For a translator or agency that works in another tool, each of these jobs used to mean a licence, a workaround or a lost client.
Taking SDLXLIFF jobs the old way
Desktop licenceCopy and pasteRebuilt files
Translating SDLXLIFF in Smartcat
Browser editorClient memory reusedSame format back
A desktop licence for one client
A client sends an SDLXLIFF file, and the only obvious way to open it is a Trados Studio seat you may not own.
Open it in the browser
Upload the SDLXLIFF, or the whole project package, to a Smartcat project. Nothing to install.
Text copied out to Word
Pasting segments into a document loses tags and segment IDs, and the file has to be rebuilt by hand.
Translate the segments in place
Smartcat splits the file into segments and keeps the structure aside, so you only ever edit the target text.
The client’s memory stays locked away
Their SDLTM or TMX sits in a format your tool can’t read, so repeat sentences get translated again.
Import their memory first
Upload the SDLTM, TMX or Excel memory and the MultiTerm glossary, and matches fill in before AI translation.
The return file breaks
A tag goes missing or moves, and the client finds out when their tool rejects the file.
Return the original format
Tags are protected and QA flags placement problems, then the file downloads as SDLXLIFF again.
SDLXLIFF, MQXLIFF, TMX and packages: which CAT tool files open in Smartcat?
Smartcat opens SDLXLIFF, MQXLIFF, TTX and XLIFF files and Trados project packages, and imports SDLTM, TMX and MultiTerm XML into its memory and glossary. A job from a desktop CAT tool rarely arrives as one file, so here is what each one is and what Smartcat does with it.
| File | Where it comes from | What it holds | In Smartcat |
|---|---|---|---|
| SDLXLIFF | Trados Studio | One document as bilingual segments with Trados markup | Upload, translate and review; download in its original format |
| SDLPPX / SDLRPX | Trados Studio project and return packages | A ZIP of bilingual files plus project resources | Upload as a supported package format |
| MQXLIFF | memoQ | Bilingual XLIFF with memoQ attributes | Upload, translate and review in the browser |
| TTX | Older Trados versions (TagEditor) | Bilingual tagged text | Upload, translate and review in the browser |
| XLIFF 1.2 / 2.0 | Most CAT tools, CMSs and authoring tools | The OASIS standard for bilingual exchange | Upload both versions; export any document as XLIFF 1.2 |
| SDLTM / TMX | Translation memories from Trados and other CAT tools | Approved source–target pairs | Import into a translation memory; export TMX or Excel |
| MultiTerm XML | Termbases exported from Trados | Approved terms per language | Import language terms into a glossary (other fields are skipped) |
Smartcat’s file-format support follows the publicly documented formats. The full list is in the Smartcat help center.
One SDLXLIFF segment, annotated
<trans-unit id="7f3c…">
<seg-source><mrk mtype="seg" mid="1">Press <g id="5">Save</g> to continue.</mrk></seg-source>
<target><mrk mtype="seg" mid="1">Appuyez sur <g id="5">Enregistrer</g> pour continuer.</mrk></target>
<sdl:seg-defs><sdl:seg id="1" conf="Translated" origin="tm"/></sdl:seg-defs>
</trans-unit>What you translate and what stays put
Unit and segment IDs
Left as they are, so the file keeps the structure your client sent.
Source
Never modified. You translate the target only.
Target
The text you translate and review, segment by segment, in the Smartcat Editor.
Inline tags
Formatting such as bold text or links, protected as tags so they can’t be typed over.
Trados metadata
Segment status and match origin. It is not text to translate, so it stays out of the editor.
How to translate an SDLXLIFF file without Trados
To translate an SDLXLIFF file without Trados, upload it to a Smartcat project, add the client’s memory and glossary, translate with AI, confirm every segment and download the file in its original format. The same six steps work for a single file, a full project package or a recurring client.
Create a project for the job
Pick the source and target languages your client set in the SDLXLIFF. One project can hold every file and language in the job.
Upload the SDLXLIFF or the package
Drop in .sdlxliff files, or the .sdlppx package the client sent. No conversion is needed before upload.
Add the client’s memory and glossary
Import their SDLTM or TMX into a translation memory and their MultiTerm XML into a glossary, so matches and terms are ready before you start.
Uploading bilingual files to Smartcat
Drop one file or a whole batch into a project. Smartcat recognizes SDLXLIFF, MQXLIFF, TTX and XLIFF, splits each file into segments and keeps its structure aside for the download.
Translate with AI, memory and glossary
Translation memory fills the segments it knows, the Content Translator Coworker drafts the rest, and the glossary keeps the client’s terms consistent.
Review and confirm every segment
Edit source and target side by side, fix QA warnings for tags, numbers and terms, and confirm each segment. Unconfirmed segments stay in the source language on download.
Download the SDLXLIFF and send it back
Download the translated file in its original format and return it to your client. Need a review copy or a memory too? Export a bilingual DOCX or a TMX.
Run one of your own SDLXLIFF files through these six steps
Open and translate SDLXLIFF files online, built for translators and agencies
Smartcat translates the SDLXLIFF file itself, so nobody copies segments into a spreadsheet or rebuilds a file by hand. It runs in the browser on Windows or Mac. Freelance translators use it to accept SDLXLIFF jobs, and agencies use it to run them with a whole team of linguists.
TM & glossary
Tags
QA checks
Team review
Other formats
See an SDLXLIFF round trip on a call with a localization specialist
SDLXLIFF packages, memories and conversions, from receipt to return
An SDLXLIFF job is more than one file. Here is how Smartcat handles what clients send, the memory and terms that come with it, and the file you deliver. For the full workflow behind it, see the Smartcat CAT tool.
Files you receive
What arrives from a client on a desktop CAT tool, and how to start with each.
A Trados project package
Clients often send an .sdlppx package: a ZIP of the bilingual files and project resources. Smartcat accepts SDLPPX and SDLRPX packages as uploads.
Ask your client which deliverable they expect back before you start: the translated SDLXLIFF files or a package.
MQXLIFF and TTX from other tools
The same project takes memoQ’s MQXLIFF and the TTX files older Trados versions produced, next to standard XLIFF 1.2 and 2.0.
Other bilingual files
.mqxliff.ttx.xlf.xliff
Assets that travel with the job
Reuse what the client already paid for, and keep it growing.
Translation memory from Trados
Create a translation memory from an SDLTM, TMX or Excel file. Every segment your team confirms is saved to it, ready for the client’s next file.
- .sdltm.tmx.xlsxImport into a translation memory
- .tmx.xlsxExport to hand back or share
Termbase as a glossary
Upload a MultiTerm XML export to a glossary and the client’s approved terms show up as you translate. Glossaries export to Excel.
MultiTerm XML brings in language terms only. Keep definitions and other fields in an Excel glossary if you need them.
What you send back
The SDLXLIFF converter question: convert SDLXLIFF to Word, XLIFF or TMX, or return the SDLXLIFF file itself?
The translated SDLXLIFF
Download the translation in its original format. Segments you haven’t confirmed stay in the source language, so confirm everything before you deliver.
- SDLXLIFF inFrom the client
- TranslateMemory, AI, glossary
- SDLXLIFF outOriginal format
Convert SDLXLIFF to Word for review
Export a bilingual DOCX, with source and target in two columns, when a client or subject expert wants to review in Word. It is a review copy: edits in it can’t be imported back. Need the translated Word document itself? Translate the client’s source .docx in Smartcat, which returns DOCX in its original format.
Bilingual DOCX
- Easy review in Word
- Export only
Translated SDLXLIFF
- Goes back to the client’s tool
- Keeps tags and segments
XLIFF for another tool or offline work
Export any document as XLIFF 1.2, work on it in another CAT tool or offline, then upload it back with Update translation and choose whether Smartcat’s own edits win.
Opening an exported XLIFF in Trados? Trados uses its own codes for some languages, so you may need to swap the language code in the file first.
The AI coworkers that translate and check your SDLXLIFF files
Each coworker handles one step of a translation job, from the first draft to the final check. Your linguists confirm every segment before you deliver.
Chief of Staff
Tell your Chief of Staff which client files and languages are due, and it coordinates the coworkers that translate and check them.
Content Translator Coworker
Drafts every SDLXLIFF segment the memory doesn’t cover, in 280+ languages, following the client’s glossary and leaving tags alone.
Content Update Coworker
When a client sends an updated file, helps find the new and changed segments so only those need new work.
Reviewer Coworker
Pre-reviews each language for fluency and terminology, so your linguists confirm a strong draft instead of starting from scratch.
Quality Assurance Coworker
Checks each translated file for terminology, number and tag errors and gives it a quality score before you deliver it.
Connect Smartcat to the tools your clients’ content lives in
Not every job arrives as SDLXLIFF. Pull files from drives, design tools, help centers and CMSs into the same workspace and memory. See all integrations
Google Drive
Translate client files shared in Drive without downloading them first.
Google Docs
Translate documents in Docs and keep the formatting.
Google Sheets
Translate spreadsheets and string lists cell by cell.
Figma
Translate design files and send the text back to the frames.
Contentful
Sync CMS entries for translation and publish them back.
Teams that manage linguists and translation memory on Smartcat
Agencies, public bodies and global companies run multilingual work with their own linguists on one platform. Each number below comes from a named customer case study.
The same linguist management, translation memory reuse and segment review are what you work with when a client’s SDLXLIFF files arrive from Trados Studio.
30%
more content, same resources
Wunderman Thompson Commerce translates 30% more content on Smartcat without adding resources.
17%
lower translation expenses
The City of Seattle reduced translation expenses by 17% by reusing previously translated content.
298
translation projects in two years
Topcon ran 298 translation projects in two years across 31 languages on one platform.
1,000 h
of admin and project management saved a year at the City of Seattle
“Smartcat’s supplier management feature alone has saved us about 1,000 hours of yearly administrative and project management time… by automating our paperwork and payment to the more than 50 reviewers that we engage regularly from our local community.”
The City of Seattle runs its language-access program with community reviewers on Smartcat. The same platform handles the reviewers’ work, their payments and the reuse of approved translations.
City of Seattle case study
See your next SDLXLIFF client job run in Smartcat
G2 Reviews
What translators ask before they take SDLXLIFF jobs in Smartcat
“My client expects files that open in Trados.”
Then send them what they sent you. Smartcat downloads the translated SDLXLIFF in its original format, with tags protected and IDs unchanged, so the client opens the same file with your translation in it.
“I work offline, and Smartcat is a browser editor.”
This is a real limit: the Smartcat Editor runs online and there is no desktop app. To work offline, export the document as XLIFF 1.2, translate it in any XLIFF tool, and upload it back with Update translation.
“The client’s memory is an SDLTM, not a TMX.”
Upload it as it is. Smartcat creates translation memories from SDLTM, TMX and Excel files, and termbases come in as MultiTerm XML, so the client’s past work fills matches from the first segment.
“Client files are under NDA.”
Smartcat is SOC 2 Type II compliant and ISO 27001 certified, encrypts files in transit and at rest, and never uses your content to train public AI models.
How Smartcat protects the client files you translate
Translation jobs carry unreleased products, contracts and customer data, often under a non-disclosure agreement. Smartcat protects that content at every step; see how on the Smartcat security page.
Role-based access controls
Set who can view, translate, review and download each client’s files by team or role on enterprise plans.
ISO 27001 certified
Smartcat is an ISO 27001 certified organization, with single sign-on through your identity provider on enterprise plans.
SOC 2 Type II compliant
Smartcat is SOC 2 Type II compliant and isolates every workspace.
Never used to train public AI models
Your clients’ content is never used to train public AI models.
Restricted downloads
Limit which linguists can download files when a client’s documents are sensitive.
Encryption and deletion on request
Content is encrypted in transit and at rest, and deleted or returned within 30 days of a written request.
Resources for translators working with SDLXLIFF files
Guides on Trados packages and the XLIFF family, and the full CAT tool behind this page.
SDLXLIFF translation FAQ
What is an SDLXLIFF file?
An SDLXLIFF file, also called an SDL XLIFF or Trados bilingual file, is the .sdlxliff file RWS Trados Studio creates when it prepares a document for translation. Smartcat reads it as XLIFF 1.2 with Trados markup: each segment holds the source text, the translation, inline tags and metadata such as segment status. It is for exchange between translation tools, not for publishing.
How do I open an SDLXLIFF file without Trados?
Upload it to a Smartcat project. Smartcat lets you open SDLXLIFF files in the browser, shows each segment’s source and target side by side, and keeps tags and structure out of your way. Translate, review and confirm segments there, then download the file in its original format. No desktop CAT tool is needed.
Can I edit an SDLXLIFF file in a text editor?
Technically yes, but Smartcat or another CAT tool is safer. In a text editor you type between XML elements and inline tags, and one deleted character can make the file unreadable for your client’s tool. A CAT tool shows only the text to translate and protects the tags, so the structure comes back unchanged.
What is the difference between SDLXLIFF and XLIFF?
SDLXLIFF is XLIFF 1.2 with Trados-specific markup added, and Smartcat reads both. The extra markup records things like segment status, match origin and comments. Standard XLIFF is the OASIS format most tools exchange. For XLIFF files from other systems, see XLIFF translation in Smartcat.
Can I open an SDLXLIFF file online for free?
Yes, for a trial period. Smartcat runs in the browser on Windows or Mac, so you can open, translate and convert SDLXLIFF files online without installing anything. Teams get a 15-day free trial with 15,000 Smartwords and no credit card. For plans after the trial, see Smartcat pricing.
Is Smartcat an alternative to Trados Studio?
For many SDLXLIFF jobs, yes. Smartcat is an online CAT tool with translation memory, glossaries, QA checks and team review that opens the files Trados produces. It is not a copy of Trados: it runs in the browser rather than on the desktop. See the Smartcat CAT tool for the full feature set.
How do I convert SDLXLIFF to Word?
In Smartcat, upload the SDLXLIFF file and export it as a bilingual DOCX from the Special formats menu. The Word file shows source and target in two columns for review, and it is export only: edits in it can’t be imported back. If you need the translated Word document itself, translate the client’s source .docx in Smartcat instead.
Can Smartcat open Trados packages (SDLPPX)?
Yes. As of October 2026, Smartcat lists SDLPPX project packages and SDLRPX return packages among its supported upload formats. A package is a ZIP that bundles the bilingual files with project resources. Before you start, ask your client whether they expect the translated SDLXLIFF files or a package back, and plan your delivery around that answer.
Can I import a Trados translation memory into Smartcat?
Yes. Smartcat creates translation memories from SDLTM, TMX and Excel files, so a client’s Trados memory can fill matches before AI translation starts. Every segment you confirm is saved back to it. To hand the memory back or share it with another vendor, export it as TMX or Excel.
Can I import a MultiTerm termbase?
Yes, with one limit. Smartcat imports MultiTerm XML files exported from Trados into a glossary, but it brings in language terms only, not definitions or other fields. If you need those attributes, use an Excel glossary, which Smartcat imports and exports with all its fields.
How do I create a translation memory from an SDLXLIFF file?
In Smartcat, attach a translation memory to the project and confirm the segments as you translate or review the SDLXLIFF; each confirmed segment is saved to the memory. Smartcat can also build a memory from bilingual documents. The memory then pre-fills matching segments in the client’s next file.
Will the translated SDLXLIFF open in Trados?
Smartcat downloads the translated file in its original SDLXLIFF format, with segment IDs and tags unchanged, so it is the same file your client sent with the translation added. If you export a document as standard XLIFF 1.2 instead, Trados may need a different code for some languages; swap the language code in the file before opening it.
Can a team of translators work on one SDLXLIFF file?
Yes. Smartcat lets several linguists work on the same project in the browser, with one shared translation memory and glossary. Invite your own translators and reviewers, or find linguists on Smartcat Marketplace on plans that include it. Users are unlimited on Smartcat plans, so adding a reviewer to a client job adds no seat cost.
Is Smartcat affiliated with RWS or Trados?
No. Smartcat is an independent platform and is not affiliated with, endorsed by, sponsored by, or otherwise associated with RWS or memoQ Ltd. Trados® is a trademark of RWS; memoQ® is a trademark of memoQ Ltd. All product names and trademarks on this page belong to their respective owners and are used only for identification.
Didn’t find your answer? Talk to a localization specialist
Trademark notice. Smartcat is an independent platform and is not affiliated with, endorsed by, sponsored by, or otherwise associated with RWS or memoQ Ltd. Trados® and Trados Studio are trademarks of RWS; MultiTerm is a trademark of RWS; memoQ® is a trademark of memoQ Ltd.
All product names, logos, and trademarks referenced on this page are the property of their respective owners and are used for identification and descriptive purposes only. Smartcat’s file-format support is built on publicly documented formats and does not imply any partnership or certification.
Say yes to the next SDLXLIFF job, whatever tool you work in
See Smartcat translate SDLXLIFF from one of your own client files, from upload to a file ready to return, or start a 15-day free trial with 15,000 Smartwords and no credit card.