Is Nylas open source? The OP was looking for an open source alternative. It is n...

r3bl · on April 1, 2017

Their clients are.

However, you would gonna need their sync-engine[0] on your own servers in order to avoid contacting Nylas servers. From what I understand, it's kind of a cloud API that makes some sense out of emailing protocols.

[0] https://github.com/nylas/sync-engine

grinich · on April 2, 2017

This is not entirely true anymore: https://blog.nylas.com/nylas-mail-is-now-free-8350d6a1044d

firloop · on April 1, 2017

Not the OP, but the Nylas mail client is open source.

https://github.com/nylas/nylas-mail