For years, I used Fastmail alongside four other email accounts with local mail clients like Thunderbird, Apple Mail, and eM Client. The experience was always just okay, but recently, tasks like opening messages, switching to folders with lots of items, or searching became frustratingly slow. Additionally, these mail clients consume more resources than I’m comfortable with, and their background processes ballooning to around 2GB on older devices with just 8GB of RAM was simply too much.
The most responsive and lightweight email experience I’ve found is, surprisingly, the Fastmail web app. However, I hesitated for a long time because using a webmail interface felt like a step backward, and I dislike more vendor lock-in. (For context, I already use my own domain through Fastmail.)
But eventually, I couldn’t stand the slowdowns anymore and made the switch. I used Fastmail's IMAP importer to fetch all messages from my other accounts, added their SMTP credentials to Fastmail for composing new emails, and enabled Fastmail's Labels feature in the settings.
Everything is better now. Processing new messages and achieving inbox zero is much faster, labels are more flexible, search is nearly instant, and the resource usage of this additional Firefox tab is significantly lower than running a native email client.
New features like Memos seem useful, but I’m still somewhat wary of the increased vendor lock-in. For example, I hesitate to use their 1Password integration with Masked Emails because I’m not sure how much of a hassle it would be if Fastmail ever turns evil, and I need to jump ship and point my domain to another email host.