I would recommend Redis. It has rich and mature functionalities. As for Google's LevelDB, it is a new born new star with great potentials. Keep an eye on it. Here is a comparison between Redis and LevelDB: http://vschart.com/compare/leveldb/vs/redis-database
Please also note the portability of LevelDb
Thanks for your reply, @kyofight!
As @RangerMauve pointed out correctly, I need an embeddable database. And looking at the comparison, I’d still favour LevelDB over Redis, since Redis offers features I’ll never need. Keeping systems as simple as possible should be everyone’s goal ;)
Aside from that, I may should have explained my use case more: The electron app needs to store RSS feeds and their items, along with some additional metadata. Nothing complex.