Jason from Elastic here.
I want to clarify this. Building a SaaS product with Elasticsearch or Kibana on the backend is okay and not prohibited, as long the service is not “managed” Elasticsearch nor Kibana. For example, a music service that uses Elasticsearch on the backend to provide music catalog search is okay. A service that offers site search powered by Elasticsearch is okay. A log search service powered by Elasticsearch is okay (again, provided it doesn’t expose Elasticsearch functionality). We welcome applications built with Elasticsearch or Kibana in the backend, even those that would be seen as competitors, as long as they are not managed Elasticsearch nor Kibana services. The Elastic License allows this, and you can do it for free. See this [item][0] in our FAQ. If you have any doubt, reach out to elastic_license@elastic.co and we would be happy to clarify.
Disclaimer: I am on the Elasticsearch team and work for Elastic; I welcome any and all feedback.
[0]: https://www.elastic.co/pricing/faq/licensing#i-build-a-saas-...