[Resolved] planning to bulk-import 70,000 translated posts

Problem:
The client is planning to bulk-import 70,000 translated posts via the native WordPress REST API using an automation tool, with the default language as Greek and importing English translations. They inquired about the JSON payload format to link English posts to existing Greek post IDs and whether any WPML processes should be disabled to enhance performance during the import.
Solution:
We do not support importing posts via the REST API, as this functionality is only officially supported for WooCommerce products. For linking posts as translations, we recommend using a hook to implement a custom solution. You can find guidance on this at https://wpml.org/wpml-hook/wpml_set_element_language_details/.
Alternatively, include the required WPML meta keys in your import file and follow our guide for importing posts or products, then connect them using our WPML Export and Import add-on. This guide can be found at https://wpml.org/documentation/related-projects/wpml-export-and-import/.
Note that you need to import both language posts and then connect them; it is not possible to connect a translation to existing content without custom code.

If this solution does not apply to your case, or if it seems outdated, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If further assistance is needed, please open a new support ticket at WPML support forum.