Tokyo Python on KaiMail: "Simple, yet flexible enough to cover our needs"

The story of how Tokyo Python ended up on KaiMail starts with me standing in front of them in April 2026, 31 slides and 20 minutes deep, with not enough time left to explain why I built this thing in the first place. I had to skip the part about why I think every developer community should be running on its own domain. I assumed I would write that argument later and let it land in its own time.

Apparently I did not need to. A few weeks later, the Tokyo Python organisers were on KaiMail with a working setup on their own domain.

Here is what their lead organiser, Ben Allen, sent us after the dust settled:

"For Tokyo Python, we wanted a cost-efficient way to handle email on our domain without running or maintaining a full mail setup. There are plenty of basic forwarding options out there, but KaiMail hits a nice balance; it's simple, yet flexible enough to cover our needs, and feels very much built with developers in mind. The documentation is clear and practical, which meant we were set up with minimal fuss."

— Ben Allen, lead organiser, Tokyo Python

"Simple, yet flexible enough" and "Built with developers in mind" are what I have been chasing since the first commit. Ben said it cleaner than I have managed to be able to write about it. (Thanks Ben!)

Your Community's Domain Is Part of Your Brand

If your group has a website at yourcommunity.org, sending announcements from gmail.com quietly chips away at trust. A consistent custom-domain inbox ([email protected], [email protected]) signals that the community is established and serious, and it keeps your archives under your own name instead of inside someone's personal mailbox.

I have made the longer version of this argument in Why Every Open Source Project Needs Its Own Domain Email. The short version: the bus factor, security reports landing in someone's Gmail, and onboarding a new co-chair by sharing passwords over LINE. I have lived through every one of those, and they are all avoidable with a domain and a forwarding service.

KaiMail is built to make that switch a five-minute job. Forward incoming mail to wherever your organisers already work, send outbound mail through authenticated SMTP, and add webhooks if you want to wire mail into your own tooling later.

Free Upgrades for Community and Volunteer Projects

Tokyo Python is on our community support program. If you organise a non-profit user group, an open-source project, or a volunteer-led initiative, we offer free plan upgrades. I do not want cost to be the reason your community ends up on a generic mailbox.

If that sounds like your group, apply through the community upgrade form. I read every application, and most decisions go out within a few days.

A genuine thank you to Ben and the Tokyo Python organisers. I have been adjacent to that community for years through PyCon JP and the regional Python community, and watching them put their domain in our hands is the kind of vote of confidence that does not get easier to receive. We will keep their inbox boring (in the best possible way) for as long as they will have us.