INFRA Signal 124
comail launches shared SMTP relay with dual DKIM signatures for atproto
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A cooperative email infrastructure that pools sending reputation via a shared relay and provides dual DKIM verification.
Engineers can send from their own domain without warming a new IP, as reputation is shared across participants. The open-source design preserves sender identity while simplifying delivery infrastructure.
Written by elseif from the cluster below · every claim links back to a sourceThe three things worth knowing
Shared SMTP relay enables domain-level email sending on atproto.
Dual DKIM signatures improve deliverability and route complaints to the correct sender.
Reputation is pooled but currently limited to a single relay operated by the project.
THE READ
What the cluster adds up to.
The introduction of comail adds a cooperative email sending path for atproto users, replacing the need for individual SMTP providers. The system replaces per-user IP warming with a shared relay that aggregates reputation. It introduces dual DKIM signatures that combine a user’s domain with the pool’s domain.
Adopting comail requires participants to run or join a relay and to expose their domain for verification, which adds operational overhead. The initial setup involves configuring DNS records, generating DKIM keys, and integrating with the atproto identity layer. Users also accept the warming tier caps that limit early volume to protect the shared IP reputation.
Current deployment is limited to a single relay, so federation and cross-pool reputation sharing are not yet available. Without multiple relays, scaling beyond the maintainer’s infrastructure depends on the operator’s resources. Features such as personal inboxes remain in early-access and are not generally accessible.
Written by elseif from the cluster below · checked for specifics the sources never containedTHE CLUSTER