IonDB vs ZeroDB: What are the differences?

Developers describe IonDB as "A key-value store for microcontroller and IoT applications". Currently in the Arduino world, there doesn't exist an associative array or map implementation that is both easy to use and performance competitive. There also is little support for disk based storage options that don't involve writing it yourself. IonDB is fast, functional, and offers disk based storage out of the box. On the other hand, ZeroDB is detailed as "Moving on-premise databases to the cloud, cheaply and securely". ZeroDB enables clients to run queries over encrypted databases without exposing decrypted data to the server and without a proxy gateway. Data at rest and in use is secure - the cloud is no longer a single point of failure.

IonDB and ZeroDB can be primarily classified as "Databases" tools.

Some of the features offered by IonDB are:

• Storing arbitrary values associated to a key
• Duplicate key support
• Range and Equality queries

On the other hand, ZeroDB provides the following key features:

• End-to-End DB Encryption
• Queries Over Encrypted Data
• Direct Cloud Sharing

IonDB and ZeroDB are both open source tools. It seems that ZeroDB with 1.58K GitHub stars and 99 forks on GitHub has more adoption than IonDB with 525 GitHub stars and 37 GitHub forks.