At present, we save emails index in SQLite, because we can run SQLite in browser (WebAssembly). We can have several databases for saving index, if they bring new values for our users (for example, if we can run Apache Lucene in browser, users could use another type of search queries).
definition of done: email indexes are saved to one more database, and we can query this database from browser (you need to implement simple HTML client to it, like we have for SQLite).
At present, we save emails index in SQLite, because we can run SQLite in browser (WebAssembly). We can have several databases for saving index, if they bring new values for our users (for example, if we can run Apache Lucene in browser, users could use another type of search queries).
definition of done: email indexes are saved to one more database, and we can query this database from browser (you need to implement simple HTML client to it, like we have for SQLite).
P.S. For example, we can try these projects: