ReadonlyREST is the only Free Software alternative to X-Pack Security for Elasticsearch.

This is a security plugin, and for it to continue being secure it needs a lot of attention. This is what constantly needs to be done:

• Fixing vulnerabilities immediately as soon as they are reported
• Loads of automated testing
• Porting code to new versions of Elasticsearch
• Maintaining backwards compatibile builds with the previous 10+ version
• Supporting you GH issues
• Keeping up our Knowledge Base Forum

Thanks to your continued support, today these major features are FREE

• LDAP connector for Authorization/Authentication
• JWT connector for Authorization/Authentication
• SSL transport for inter-node
• SSL transport for HTTP

Why to donate?

For the ponies!

Well, also. But also because the alternative would be to pay for a basic X-Pack license: many tens of thousands dollars for a handful of nodes.

So, because there's nothing worse than half assed security: either it's done seriously, or it's better to shut it down.