Workers
API and inbound processing
Serve authenticated mailbox routes and process Email Routing events.
Direct answer
Can I self-host email for AI agents?
Yes, if your team is prepared to own domain, data, sender configuration, migrations, monitoring, abuse controls, and incidents.
Direct answer
Yes. mails0 is MIT licensed and documents a self-hosted architecture on Cloudflare Workers, D1, R2, and Email Routing. You provide the Cloudflare account, domain, secrets, database and bucket, outbound sender provider, quotas, retention, monitoring, and operational response. Self-hosting gives control but does not eliminate email operations.
Decision map
The documented Cloudflare architecture
- 01API and inbound processing
Serve authenticated mailbox routes and process Email Routing events.
- 02Queryable metadata
Store identities, token state, message indexes, labels, threads, and quotas.
- 03Raw message storage
Preserve MIME and attachments under explicit retention and access policy.
Stack
The documented Cloudflare architecture
D1
Queryable metadata
Store identities, token state, message indexes, labels, threads, and quotas.
R2
Raw message storage
Preserve MIME and attachments under explicit retention and access policy.
Deployment
Build the service in verifiable stages
-
01
Create and migrate resources
Provision D1 and R2 and apply the current schema with compatibility checks.
-
02
Deploy and configure secrets
Store secrets in Cloudflare and verify the Worker health endpoint.
-
03
Route inbound mail
Use a dedicated subdomain and send an external message through Email Routing.
-
04
Configure outbound separately
Verify the sender provider and track acceptance and delivery states independently.
-
05
Harden operations
Set limits, retention, cleanup, monitoring, backups, and incident controls.
Tradeoff
Control and responsibility arrive together
Self-hosting is valuable when your domain, data location, source review, quotas, or integration behavior are requirements. It is not automatically simpler or cheaper than a managed provider.
Your team must own DNS, sender reputation, migrations, secret rotation, Cloudflare limits, monitoring, backups, abuse response, and updates. Choose a managed service when reducing those operations is the higher priority.
- Use a subdomain to protect existing human mail.
- Keep operator and mailbox credentials separate.
- Test external inbound and outbound paths.
- Document retention and deletion before production data arrives.
Decision
Hosted sandbox or self-hosted
| Requirement | Use hosted sandbox | Self-host when |
|---|---|---|
| First proof | You need one temporary receive-only mailbox. | You already know the production requirements. |
| Domain | Hosted domain is acceptable. | The agent must use your domain. |
| Data | Hosted service boundary is acceptable. | Mailbox data must stay in your account. |
| Sending | Hosted capability and limits fit. | You need your own sender and policy. |
| Operations | You want minimal setup. | Your team can own the full lifecycle. |
Implementation judgment
Self-host only when ownership is part of the requirement
The architecture is practical, but production readiness includes more than deployment. Assign ongoing responsibility for DNS, provider configuration, migrations, retention, monitoring, backups, abuse controls, key rotation, and incident response before moving durable agent identities onto the service.
Evidence
Sources and product scope
Product behavior is verified against the mails0 source and documentation. External comparisons link to official vendor documentation checked on 2026-08-15.
- mails0 source repositoryImplementation, license, and deployment source
- mails0 self-hosting guideDeployment instructions
- Cloudflare Email Service docsOfficial platform behavior
Questions and answers
Related questions
Is the self-hosted code free?
mails0 is MIT licensed. Cloud, provider, domain, and engineering costs remain separate.
Can Cloudflare Email Routing send email?
No. It routes inbound email. Configure a verified outbound sender provider for sending.
Can I use my root domain?
You can, but a dedicated subdomain is usually safer when the root domain already handles human email.
Start with a bounded inbox
Give the agent an inbox, then prove the workflow.
Start with a receive-only temporary mailbox. Move to a permanent identity or self-hosted deployment only after the workflow reaches a real email value event.