I run bandgap.io off of protonmail. I have had no problems with deliverability, have had great interactions with customer support, and enjoy using the product.

I run bandgap.io off of protonmail. I have had no problems with deliverability, have had great interactions with customer support, and enjoy using the product. After email hack after hack, I just couldn't see how I could ethically store my own users support emails unless they were end-to-end encrypted. Potential improvements: Searching the inbox isn't great, and I'd like to reduce my attack surface by moving my transactional email from sendgrid to protonmail (not yet supported). Also, it might make sense for protonmail to become an OAuth provider-I'd be willing to support it on bandgap.io