Confidentiality with DeepL Translations. Is It Secure?

1. What is DeepL Translation?

1-1. Machine translation services became available in Japan from 2020

DeepL Translation is a machine translation service developed by DeepL, a company based in Germany, in 2017. In 2020, Japanese was added to the supported languages, leading to its widespread use in Japan. The company's predecessor, Linguee, previously offered an online dictionary service. Utilizing high-quality data from the past, DeepL Translation is regarded as providing natural and highly accurate translations compared to other machine translation services.

1-2. Translatable Languages

As of May 2025, DeepL Translator supports 35 languages. It covers languages from major regions around the world, including Western countries, making it sufficient for general business use. In recent years, the number of supported Asian languages has increased, and it currently supports Japanese, Chinese (Simplified and Traditional), Korean, and Indonesian.

1-3. What is the new feature "Clarify"?

In March 2025, DeepL released a new feature called "Clarify." This feature utilizes the latest large language model technology and serves as an AI assistant to make translations easier to use and more accurate.

A key feature of Clarify is that it allows users to interact during translation to clarify ambiguous parts. For example, the AI asks questions about words with multiple meanings, gender distinctions, personal and place names, numerical expressions, idioms, cultural differences, abbreviations, and technical terms. By answering these questions, users can obtain more accurate translation results.

This feature enables even those who are not familiar with languages to translate subtle nuances accurately, significantly improving the precision of translations used especially for work.

Currently, Clarify is available to DeepL Pro plan users and can be used for translations between English and German.

2. Advantages and Precautions of Using Machine Translation

 

Here, we will introduce the benefits and considerations of using machine translation.

2-1. Benefits of Using Machine Translation in Business

・Cost Reduction
Since there is no need to outsource translation, it is possible to reduce costs. Recently, many companies offer free machine translation services, which leads to a reduction in labor costs. Additionally, if you desire higher accuracy translations and more comprehensive services than those provided by free versions, adopting a paid version can also be an option.

・Immediate translation available as needed
Machine translation has the advantage of being faster than human translation. While a human translator can handle approximately 1,500 to 2,500 words per day, machine translation can translate text in a matter of seconds to tens of seconds. Since the translation results can be checked immediately, it can also be used for translating urgent documents.

2-2. Points to Note About Machine Translation

・Clarify the subject of the sentence before translating
When translating from Japanese to a foreign language, it is necessary to clarify the subject of the original sentence before translating. Compared to foreign languages, Japanese often conveys meaning without explicitly stating the subject. On the other hand, if you translate into a foreign language without clarifying the subject, there is a high risk that the meaning of the sentence will change. To reduce mistranslations and revision time, be sure to clarify the subject before translating.

・Ensure Security Is Fully Guaranteed
Depending on the service, free versions of machine translation may not provide complete security. You must be cautious about the translated text data remaining on the service provider's servers and the potential leakage of data information. As a preventive measure, switching to a paid version of the translation service during the period of use could be an option. When selecting machine translation for business use, carefully consider which services offer high confidentiality.

3. DeepL Security

It is important to consider security aspects when implementing.
There are many automatic translation services available for free on the internet, but most free services do not guarantee confidentiality. DeepL is no exception.

 

First, there are two types of services offered by DeepL.

・DeepL Translation

・DeepL Pro

 

There is the following description about this DeepL translation. (Our company's summary)

"Processing of Submitted Content
When using our free services, we reserve the right to process the content you upload (such as text and documents) and its translations/improvements for a certain period for the purpose of training and improving our neural networks and algorithms. This also applies to any adjustments or corrections you make to our translation or improvement suggestions. When using the glossary feature and entering specific term pairs, this data is stored locally only. Therefore, glossary entries cannot be used on a different browser or device."

We reserve the right to transfer your content to third-party servers in order to provide our services. These third parties are our data processors, and we have concluded data processing agreements with them. As a result, these third parties can only process data according to our instructions and do not process data for their own purposes.

Please note that the free service cannot be used to process any content containing confidential information or personal data. Personal data here refers to any information relating to an identified or identifiable natural person. Submission of content containing confidential information and/or personal data is only permitted within a DeepL Pro subscription."
（https://www.deepl.com/en/terms-of-use）

It is stated that the entered text and documents may be used for improving DeepL's services. It is clear that using DeepL translation for business documents containing confidential information poses a significant issue.

On the other hand, there is the following description about DeepL Pro. (Our company's summary)

"3.1.2 DeepL temporarily stores content or processed content only to the extent technically necessary to provide the service. Further storage of content or processed content occurs only upon customer request (such as using the 'Saved Translations' feature). To avoid any doubt, DeepL reserves the right to create and retain access logs for billing, security, and statistical purposes. These access logs do not include content or processed content. However, access logs may include metadata of API requests, such as the time of the API request and the size of the submitted content."
(https://www.deepl.com/en/pro-license)

Additionally, there is the following description regarding security. (Our company's summary)

"Data exchange between the customer and the DeepL server is conducted via a state-of-the-art encrypted internet connection." (https://deepl.safebase.us/?itemName=data_security&source=click&itemUid=4ea65d1e-79fb-47cf-95a8-bdb24d2d6a4b)

Communications are encrypted to ensure confidentiality.
By using DeepL Pro, content or processed content is temporarily stored on the server only to the extent technically necessary to provide the service as described above, ensuring confidentiality both during transmission and on the server.

Regarding DeepL Pro's privacy policy, DeepL also provides a separate page titled "Secure Language AI Solutions for Global Enterprises" (https://www.deepl.com/ja/pro-data-security).
"In-memory processing: Text is never stored without the customer's consent."
To reiterate DeepL's personal data protection policy, it states that text is not stored when using DeepL Pro.
In other words, when translating business documents containing confidential information, using DeepL Pro is essential.

 

Related Blog Posts

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What is the translation accuracy of DeepL in medical translation? Comparison results with Google/Microsoft/Amazon

 

Features of MTrans for Office

1. ① No limit on the number of files that can be translated or on the glossary, with a flat-rate system
2. ② Translate with one click from Office products!
3. ③ Security is also assured with API connection
   ・For customers who want further enhancement, we also offer SSO, IP restrictions, and more
4. ④ Support in Japanese by Japanese companies
   ・Response to security check sheets is also available
   ・Payment by bank transfer is available

 

MTrans for Office is an easy-to-use translation software for Office.