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Purelymail Calendar vs Fastmail Calendar
Fastmail Calendar is a paid, fully integrated scheduling product built into the Fastmail web interface. Purelymail by itself ships CalDAV calendar storage without a comparable scheduling UI. Purelymail Calendar is an unofficial open-source web app that fills the gap for Purelymail users.
The pairing is independent of Purelymail and free to use; you only pay for your underlying Purelymail mailbox. The events still live in Purelymail's CalDAV calendar.
Architecture at a glance.
Fastmail Calendar
Purelymail (raw)
/webdav/.
Purelymail + Purelymail Calendar
Purelymail Calendar replaces only the front-end and scheduling layers. Storage and identity stay on Purelymail.
Feature by feature.
| Capability | Fastmail Calendar | Purelymail (CalDAV only) | Purelymail Calendar |
|---|---|---|---|
| Web calendar UI | Yes, built in. | No. | Yes (month / week / day views). |
| iTIP meeting invites | Yes, built in. | No. | Yes (REQUEST / CANCEL). |
| RSVP tracking | Yes, built in. | No. | Yes (IMAP poll, PARTSTAT applied). |
| Recurring events | Yes. | Storage only. | Yes (with single-occurrence cancel). |
| Inbox invite sync | Yes. | No. | Yes (every 5 minutes). |
| Email + calendar bundled price | Yes (single Fastmail plan). | Yes (Purelymail plan, typically cheaper). | Free; uses your Purelymail mailbox. |
| Source available | No (proprietary). | No (proprietary server). | Yes (MIT licensed). |
| Self-hostable | No. | No. | Yes (Docker compose ships in the repo). |
| Hosted by | Fastmail. | Purelymail. | You, or purelymailcalendar.com. |
| Native mobile apps | Yes (iOS, Android). | Use any CalDAV client. | Web only today. Use Apple Calendar or DAVx5 alongside. |
| Search across email and calendar | Yes (unified). | No (separate clients). | Not unified with mail. Calendar search only. |
How to choose.
Pick Fastmail Calendar if
You want a single paid vendor for email and calendar with first-party mobile apps, unified email-and-calendar search, and zero setup beyond signing up. The scheduling and inbox sync just work, and there is no companion app to install.
Pick Purelymail plus Purelymail Calendar if
You already use Purelymail and want the cheaper mailbox while keeping a real scheduling layer, you prefer an open-source companion app you can audit or self-host, and you are comfortable using a CalDAV client on mobile until native apps exist.
Pick Purelymail without Purelymail Calendar if
You only need calendar storage that syncs to Apple Calendar, Thunderbird, or DAVx5, and you do not need to send standards-compliant meeting invites or track RSVPs.
Where to go next.
- Sign in to Purelymail Calendar and try the scheduling layer on top of your existing Purelymail CalDAV calendar.
- Does Purelymail have a calendar? (full feature comparison page).
- Send meeting invites with Purelymail: the iTIP/iMIP flow.
- Connect Purelymail CalDAV to Apple Calendar for native device sync.
- Purelymail's CalDAV docs and Fastmail's calendar page for the vendor sources.
- Source on GitHub (MIT licensed).
- About Purelymail Calendar: credential handling and data residency.