⚠️ [DeepL] Critical Action Required: Update Auth by 2026-01-15

[shirgoldbird]

Hi OmegaT team,

👋🏻 Shir here from DeepL. We're writing to inform you of an important upcoming change to the DeepL API. If you do not take action, your DeepL integration will no longer work after January 15, 2026.

What’s Changing

Effective January 15, 2026, DeepL will discontinue support for the following legacy authentication methods:

• auth_key in query parameters
• auth_key in form body data
• auth_key in JSON body data

After this date, all API requests must use the standard Authorization header for authentication.

What You Need to Do

Update your DeepL API integration to authenticate using the Authorization header:

Authorization: DeepL-Auth-Key YOUR_API_KEY

Full migration instructions and code examples are available in our documentation.

OmegaT Specifics

PR #57 from @ychoi-kr is already compliant with this request, and if merged in, should avoid this issue. (This deprecation was also flagged prior on the OmegaT developers mailing list, though it didn't seem like there was any further discussion about it.)

Our team is here to support your migration. If you have questions or need assistance, let us know. Thank you for your continued partnership with DeepL!