InboxOS
Overview
InboxOS is a complete email system a team deploys to its own Cloudflare account. Everyone gets a real address on their domain, shared addresses can be read and answered together, and an admin console covers people, mailboxes, domains, security, compliance and health. There are no servers to look after. The whole product is one Worker with a D1 database and an R2 bucket.
Challenge
It started in August 2026 to run email for a small agency team: a handful of personal inboxes, shared addresses across more than one domain, and several people working the same inbox without stepping on each other. The options were per-seat suites built for much bigger companies, or self-hosted mail servers that need constant care.
Outcome
In daily use from the end of August, then turned into a product anyone can install: a setup wizard, use-case presets, a theme studio and a health center. InboxOS 1.0 was released as free software under the AGPL on October 13, 2026.
Key features.
- 01Personal and shared mailboxes (hello@, support@) across several domains, with an All inboxes view
- 02First-run setup wizard: owner account, brand, provider key, live DNS checks, mailboxes, invites and a real send test
- 03Shared-inbox teamwork: assignments, open/pending/closed, internal notes, @mentions and collision warnings
- 04Admin console with a health center, ⌘K palette, bulk actions and CSV import/export
- 05Passkeys, enforced 2FA, SCIM, retention, legal hold, eDiscovery, DLP and a full audit log built in
- 06Use-case presets and a theme studio, plus a REST API, MCP server and signed outbound webhooks
Three weeks to daily use
The first version took about three weeks of evenings and weekends: a Worker for the API, D1 for data, R2 for message bodies and attachments, Resend for delivery, and a React app on top. Each week of real use added the next piece: an API and MCP server, multi-domain mailboxes, an installable phone app with push notifications, mail rules and a security center.
Set up in the browser
A fresh deploy opens a wizard that goes from an empty URL to working mail: owner account, brand, provider key, DNS records checked live, mailboxes, invitations and a real send-and-receive test.
Built for the people running it
Health checks with one-click fixes, a dashboard, bulk actions, CSV import and export, a ⌘K palette, use-case presets that switch on the right features, and a theme studio with JSON import and export.
Serious where it counts
Passkeys, enforced two-factor, SCIM provisioning, retention, legal hold, eDiscovery, DLP and a full audit log come built in rather than as an upsell.
Stack
The screens.
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