Verified against the LocalePilot source code on 30/10/2026 (commit b84b323). DeepL requires LocalePilot Pro.
What is sent
Texts are sent in groups of up to 50. For each text:
- the source text. Placeholders are replaced by numbered markers that DeepL leaves untouched, then put back;
- a context that DeepL uses to translate better: the key name and, if they exist, the description and group of the key.
For the whole request:
- the source and target language codes;
- the formality, if you set Formality (supported languages only) and the target language supports it;
- the reference of your glossary in DeepL, if Use approved glossary is on (Pro) and approved terms exist for the target language.
Messages with ICU plurals or selections are not sent: they need an AI model.
What is never sent
- Neighboring keys, translations in other languages and the current translation.
- The project's Translation context.
- Glossary notes and scope, forbidden terms and terms that are not approved.
- Your files, their names and their paths, and the name of your project.
- Store listings: Adapt with AI needs an AI model.
- Translations to audit: the AI audit needs an AI model.
The glossary in your DeepL account
To apply your approved glossary, LocalePilot creates a glossary in your DeepL account, one per language pair. Its name starts with LocalePilot-, followed by the two languages, for example LocalePilot-EN-FR-…. It holds only the source and target of each approved term for that target language.
When your approved terms change, LocalePilot creates a new glossary for the pair, then deletes its earlier ones for the same pair. It only deletes glossaries whose name follows this exact pattern, never the others in your account.
- If several projects use the same DeepL account and the same language pair, each one replaces the glossary of the other when it translates.
- If your account has reached its glossary limit, LocalePilot first deletes its own earlier glossaries. If there is still no room, it translates without the glossary and tells you so.
- If two approved terms have the same source with different targets, no glossary is created and the translation runs without one.
You can see and delete these glossaries at any time in your DeepL account.
API key and address
Add your key in Settings, AI provider, with Add a key. It is stored in the macOS Keychain, never in LocalePilot's settings file, and sent in an Authorization: DeepL-Auth-Key header.
The address cannot be changed, so that your key never goes anywhere else: a DeepL API Free key (ending in :fx) goes to https://api-free.deepl.com, any other key to https://api.deepl.com. Test reads the usage of your account, without any of your text.
Options that change what is sent
- Use approved glossary (Pro): off, no glossary is created or used.
- Formality (supported languages only): sent only for target languages that support it.
- Translate automatically with …, in Add a language: checked by default, it translates a new language as soon as you add it, with the approved glossary.
The key name, description and group are always sent as context: no option leaves them out.