The 5 Best Translation Tools That Don't Train on Your Data (2026)

every listicle about "best translation tools" leads with features. language pairs. UI design. integrations.

none of them lead with: what does this tool do with your text after you hit translate?

I wanted to make a different kind of list. one that starts with the criteria that actually matter when you're translating sensitive documents, and then evaluates tools against those criteria. not vibes. not "it feels secure." verifiable claims.

so here it is. five tools where "we don't train on your data" isn't just marketing copy.

What 'doesn't train on your data' actually means

before we get to the list, let's be precise. because "no training" gets thrown around by tools that absolutely do use your data in other ways.

model training means your text is used as input data to improve or fine-tune the translation engine. your contract clause becomes part of the dataset that makes future translations better. this is the big one — once your text is in a training set, it's effectively irrecoverable.

fine-tuning is a subset of training where your text improves the model for specific tasks or domains. some tools offer custom glossaries or "adaptive" translation that technically use your content to adjust outputs. this is training with a friendlier name.

logging is different from training, but still matters. a tool can promise "no training" while still logging your full translation requests for debugging, analytics, or abuse detection. your text isn't improving the model, but it's sitting in a database.

caching is even subtler. some services cache recent translations for performance. it's not training, it's not logging, but your text is still temporarily stored.

when I evaluate "no training," I look for all four:

1. no model training on customer content
2. no fine-tuning using customer text
3. no persistent content logging (metadata logging is okay — content logging is not)
4. clear retention policy with specific timeframes

if a tool satisfies 1 and 2 but not 3 and 4, it's better than the free tier — but it's not actually "no training" in the way most people mean it.

The 5 evaluation criteria

for this list, every tool was evaluated against these five criteria:

#	Criterion	What I checked
1	No training	Contractual commitment that customer content is never used for model training or fine-tuning
2	Retention window	How long content exists on their systems, and whether deletion is hard (permanent) or soft (recoverable)
3	Data residency	Where content is processed, and whether EU-only processing is available or default
4	DPA available	Whether a data processing agreement is available for GDPR compliance
5	Verifiability	Whether the claims are backed by published documentation, not just sales calls

I deliberately excluded quality, language coverage, and pricing. those matter, but they're covered everywhere else. this list is purely about data handling.

The 5 tools

1. noll

what it is: a stateless document translation tool with zero-retention architecture. no accounts required. files are translated and deleted within 30 minutes.

Criterion	Evaluation
No training	Never. No proprietary model — routes through enterprise APIs with contractual no-training guarantees
Retention window	30 minutes, hard delete. No backups, no content logs, no recovery
Data residency	EU-only by default. No configuration needed
DPA available	Yes
Verifiability	Architecture documentation published. No translation history or dashboard exists to audit because no data persists

strengths: the strongest retention guarantee on this list. format preservation for PDF and DOCX. no account required, which means no identity linkage. the stateless design is the simplest architecture to verify.

limitations: no translation history, glossary management, or quality customization. no SOC 2 or ISO 27001 certification yet. the 30-minute window means you must download promptly.

disclosure: I'm a co-founder. I included noll because it meets the criteria, not because it's mine. judge it by the same standards as the rest.

2. DeepL Pro (API tier)

what it is: the paid tier of DeepL's translation service, specifically the API product (not the web translator).

Criterion	Evaluation
No training	Pro/API users' content is not used for training. Contractually stated
Retention window	"Deleted after processing." Specific timeframe not prominently documented
Data residency	EU processing (Cologne-based). Enterprise tiers offer additional guarantees
DPA available	Yes (Pro and higher)
Verifiability	Privacy policy and security page published. Enterprise customers can request detailed security documentation

strengths: excellent translation quality. glossary and formality features. well-known brand that procurement teams recognize. strong GDPR posture as a German company.

limitations: the web interface and API have different data handling terms. retention window isn't specified to the level some compliance teams need. free tier does train on data, so you need to ensure every user is on Pro.

important: "DeepL Pro" means the API. the web translator, even on a Pro plan, may have different terms. verify which product your team is actually using.

3. Google Cloud Translation API

what it is: Google's enterprise translation API (not the consumer translate.google.com product).

Criterion	Evaluation
No training	Customer data submitted to Cloud Translation API is not used to train Google models
Retention window	Transient processing. No persistent storage of translation content
Data residency	Configurable to EU regions
DPA available	Yes (Google Cloud DPA)
Verifiability	SOC 2, ISO 27001, extensive compliance documentation

strengths: strongest compliance documentation on this list. broadest language coverage. configurable processing regions. Google's infrastructure security is industry-leading.

limitations: requires GCP account and technical setup. the consumer Google Translate product trains on data — you need to ensure employees use the API, not the website. residency requires configuration and monitoring.

critical distinction: google.com/translate and the Cloud Translation API are different products with different policies. if your IT team says "we use Google," make sure they mean the API.

4. Microsoft Azure Translator

what it is: Microsoft's enterprise translation API, part of Azure Cognitive Services.

Criterion	Evaluation
No training	Azure Translator does not use customer data to train or improve Microsoft translation models
Retention window	Content is not persisted after translation in the standard tier
Data residency	Azure region selection available, including EU regions
DPA available	Yes (Microsoft DPA / OST)
Verifiability	SOC 2, ISO 27001, extensive Azure compliance certifications

strengths: strong enterprise controls within the Azure ecosystem. custom translator feature (you can train your own model, which is different from Microsoft training on your data). broad compliance certification portfolio. integrates with Microsoft 365 workflows.

limitations: requires Azure subscription and configuration. custom translator feature means you choose to use your data for training your own model — make sure employees understand the distinction. like Google, the API and any consumer-facing features have different terms.

5. Trados (RWS)

what it is: an enterprise translation management platform used by professional translation teams and LSPs.

Criterion	Evaluation
No training	Customer translation memories and content are not used for training RWS models in the enterprise tier
Retention window	Customer-controlled. Data persists as long as you keep it in the TMS
Data residency	Configurable (on-premise option available for maximum control)
DPA available	Yes
Verifiability	ISO 27001 certified. On-premise deployment option allows full infrastructure control

strengths: customer-controlled retention (you decide when data is deleted). on-premise deployment option for organizations that can't use cloud services. translation memory and terminology management. well-established in regulated industries (pharma, legal, financial services).

limitations: not a simple "upload and translate" tool — it's a full TMS designed for professional translators and localization teams. significant setup and licensing costs. overkill for teams that just need to translate a few documents.

How to verify 'no training' claims yourself

any vendor can say "we don't train on your data." here's how to verify it:

1. read the privacy policy, not the marketing page. marketing says "secure." the privacy policy says what they actually do with your data. look for specific language about model training, machine learning, and service improvement.

2. request the DPA. the data processing agreement is a legally binding document. if it says "no training," that's enforceable. if it says "we may use data to improve our services," that's training with extra words.

3. ask about logging. "no training" and "no logging" are different things. ask specifically: do you log translation request content? for how long? who can access it?

4. check the subprocessor list. where does your data actually go? if the vendor routes through third-party APIs, those subprocessors also need no-training commitments.

5. test the deletion claim. translate something. wait for the stated retention window. try to access it again. if you can, the deletion claim is... aspirational.

What to do if your tool isn't on this list

if you're currently using a tool that trains on your data (or you're not sure), you have three options:

1. upgrade to a no-training tier. most tools offer this — but verify it's the API tier, not just a label on the same product.

2. switch tools for sensitive work. use your current tool for low-sensitivity translations, and a zero-retention tool for sensitive documents.

3. implement a classification policy. define what's "sensitive" in your organization, and require a specific tool for that category. this is the most practical approach for most teams.

the worst option is doing nothing and hoping nobody notices.

Takeaways

• "no training" has a specific meaning — check for model training, fine-tuning, content logging, and retention
• the web interface and API often have different policies for the same vendor
• all five tools on this list meet the no-training bar, but they serve different use cases and team sizes
• always verify claims through the DPA and privacy policy, not the marketing page
• if your current tool trains on your data, classify your documents and use the right tool for the right risk level

Further reading

• noll vs DeepL Pro vs Google Cloud Translation: Which Is Actually Safest?
• The 'Stateless' Translation Revolution: Why Storage is the Enemy
• Which translation services should I use for sensitive documents?
• Why not Google or DeepL?