Proton Mail is privacy-first and excellent at it, but custom domains sit on paid plans and provisioning means adding and verifying DNS records yourself. Email Inbox provisions a catch-all inbox on your domain automatically via Cloudflare OAuth — receive, send, search, and thread, with no manual DNS.
Custom domain on the base flow, not a paid add-on
No manual DNS verification — automatic MX and SPF
Catch-all inbox across your whole domain
Send and reply from your domain
Comparison
Encrypted email provider with custom-domain support on paid plans.
| Feature | Email Inbox | Proton Mail |
|---|---|---|
| Runs on your own domain | Yes, catch-all by default | Yes, on paid plans |
| Hosting | Your Cloudflare account | Proton's servers |
| End-to-end encryption | Transit + at rest in Kiap | Yes, by default |
| Setup | OAuth + pick domains, seconds | Add DNS records + verify |
| Best for | Domain owners wanting control + tooling | Privacy-first individuals |
Comparison reflects general product positioning as of 2025. Verify with each provider's current plans.
Authorize Kiap to manage Email Routing and deploy a Worker. One scoped OAuth consent screen — no API tokens to create or paste.
Pick one or more domains from your Cloudflare account. Kiap enables Email Routing, deploys a Worker, and wires a catch-all rule.
Kiap deploys a Worker per domain, turns on Email Routing with the right MX and SPF records, and creates the catch-all route. A few seconds per domain.
Proton Mail provides end-to-end encryption by default, which Email Inbox does not replicate. Email Inbox secures mail in transit and at rest, and gives you control by running on your own Cloudflare account. If zero-knowledge encryption is your top priority, Proton is the stronger choice; if you want mail on your domain fast with tooling around it, Email Inbox is simpler.
No. Kiap deploys a Cloudflare Worker to your account and uses Cloudflare Email Routing for inbound mail. There is no Postfix, no Dovecot, and no server to keep patched. You approve one OAuth consent screen and Kiap provisions everything.
No. Authorization happens through Cloudflare OAuth. You approve a scoped consent screen in your browser. Kiap never sees your Cloudflare password and you never paste a token.
Yes — that is the whole point. Pick any domain on your Cloudflare account and Kiap provisions a catch-all inbox on it. Every address on that domain lands in your inbox by default.
Yes. Select one or many domains during setup. Each gets its own Worker and catch-all route, and all mail arrives in one inbox you can search and thread.
Yes. Outbound mail goes through the same Cloudflare Worker using Cloudflare's send_email binding, so you send from your own domain. Replies, reply-all, forwarding, HTML and plain text, and attachments are all supported.
Email Inbox runs on Cloudflare's free Email Routing tier and a free-tier Worker. You bring the domain. Check the Kiap pricing page for plan details.
Authorize Cloudflare, pick your domain, and you're sending from it in minutes.