Searchable 
This extension provides an API to easily use Elasticsearch in complex TYPO3 instances.
Features:
- Out-of-the box indexing of pages
- Indexing of extension content via minimal configuration (TCA based indexing)
- Multilanguage support
- Command-line indexing
- Highly configurable
- Highly extendable with your own code
In addition to the already supported features, it is very easy to add your own code if necessary. No need to write a complete indexer from scratch, instead you can register custom classes for almost every sub-process like preview rendering, link generation and more.
Testing
All tests can be executed with the shipped Docker Compose definition:
docker-compose run --rm app composer build