Proton Mail vs Yahoo! JAPAN Mail

Proton Mail is an encrypted email service available on the web, Windows, macOS, Linux, iOS, and Android. Its free plan lists 1 GB of storage and one email address, although its FAQ says storage starts at 500 MB; the free tier is described as having the same security level as paid plans. The service uses end-to-end and zero-access encryption, with open-source apps and independent audits. It blocks email trackers and includes phishing and spam protection, password-protected messages, and link confirmation. Users can schedule, undo, or snooze emails and organize messages with folders, labels, and categories. Easy Switch imports email, calendars, and contacts from other providers. Paid plans support external email clients through IMAP and SMTP using Proton Mail Bridge. Mail Plus lists 15 GB of storage, 10 extra email addresses, and one custom domain. Paid subscriptions include a 30-day money-back guarantee, and the desktop app has a 14-day free trial. Paid plans display monthly billing; the listed starting price is 3.99 /user/mo.

Yahoo! JAPAN Mail has no write-up on Specifiction yet; its figures are above.