Files
selfpost/docs/product.md
T
mixandClaude Opus 5.5 ed3cb4aaac docs: the panel as it is in 2.0
Stage 3, step 3. Written by Sonnet from the code and the plan, checked
by Opus.

  - guide.md: a section on the panel - menu, paths, the roles global and
    domain with outbound and inbound assigned separately -, Overview and
    Health, Queue and System log, Account and Server > Settings, the
    domain page / Domain settings / application form, Help as a page of
    topics. The DMARC report address is one of three choices set in
    Domain settings. The Spam filter box, the two INBOUND_ANTISPAM_*
    variables the panel reads, and the filter's socket on Health.
    Sessions; backup and export encrypted unless the box is unticked;
    1.x data is not restored into 2.0.
  - architecture.md: Panel HTTP surface rewritten from web.go (routes,
    the /server/ guard, per-object checks, <page>/fragment, one layout,
    typed page data, the kit and its guards, CSP and htmx); Persistence
    gains the database - one baseline, a 1.x file refused, the tables as
    they are.
  - security.md: roles and what each reaches, as built; sessions by user
    id and what ends them; state-changing requests; errors shown to
    users; the 2.0 review; two accepted risks from it - a delegated
    inbound upstream may be any host and port, and Account's profile is
    saved without the password.
  - CHANGELOG: Removed opens with "2.0 starts from an empty data
    directory"; entries that describe the user-default report address
    say they were replaced before release; the filter's socket.
  - roadmap.md: two review follow-up rows struck as retired by the
    redesign (.pair / .split, the two back links); password-reset notes
    that changing the account e-mail must then ask for the password.
    Progress 25/27.
  - development.md: the component kit and its guards; README and
    product.md: wording.

Left as they are
  - The third follow-up row the plan expected to strike - initShowWhen
    is not re-run after an htmx swap - still holds: no polled fragment
    carries such a control today, so nothing breaks, but the redesign did
    not retire it.
  - guide.md embeds no screenshots, so none needed retaking.
  - README and guide still name image 1.9.5 - the version cut.
  - plans/preflight.md and plans/inbound-antispam-panel.md use pre-2.0
    paths; roadmap's template-data-typing is largely done by the
    redesign.

  go test -count=1 ./cmd/panel (env-doc tables): ok

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-10 13:01:18 +03:00

4.9 KiB

SelfPost — product boundaries

What this file is. Stable product definition for SelfPost v1.0: purpose, deployment assumptions, explicit out-of-scope items, and the multi-domain model. User-facing overview in README.md; install and operations in guide.md; as-built technical detail in architecture.md.


Purpose

SelfPost is a self-hosted SMTP relay with a web control panel, shipped as a single Docker image. It sends mail directly from your server with per-domain DKIM signing; an optional inbound relay forwards mail on port 25 without storing it.

Primary workflow: configure the relay once (domains, DKIM, SASL applications), then point scripts and apps at the SMTP endpoint. SelfPost delivers as the configured sending domain.

Positioning

Text
Stamp subtitle SELF-HOSTED SMTP RELAY
Wordmark The stamp's own letter outlines without the stamp (docs/assets/selfpost-wordmark.svg, -ink for light grounds) — for places too small for the stamp, such as the panel header
Tagline YOUR SMTP. YOUR RULES.
Hero line (README, GitHub) Self-hosted SMTP relay with a web panel — one Docker image, no provider.

Brand assets and metrics: docs/assets/selfpost-proof.html.


Deployment context (fixed assumptions)

These constraints are intentional; changing them requires an explicit product decision:

  1. VPS or home server — one image for both. Raspberry Pi and similar boards are not a current target but not ruled out forever.
  2. Send from your own IP (DIY) — no intermediate relay provider. Requires outbound port 25, static IP, and configurable PTR/rDNS from the operator.
  3. Single container — Postfix, OpenDKIM, and the panel run under one supervisord inside one image.
  4. Panel is internet-facing — mandatory security requirements in security.md.

Infrastructure the operator provides (not SelfPost features): unblocked outbound TCP 25, static IP, PTR/rDNS, acceptable IP reputation. SelfPost does not detect, bypass, or compensate for missing prerequisites; mail simply fails to deliver when they are absent.


Out of scope

Explicitly excluded to prevent scope creep:

  • Inbound mail (IMAP/POP3, mailboxes, delivery to user inboxes)
  • Webmail
  • Organisations / tenancy beyond the global and domain roles; managing multiple sending domains under one global administrator is in scope (see below)
  • Inbound antispam/antivirus engines (rspamd, ClamAV, etc.) — SelfPost may expose a milter hook; it does not ship or start a filter
  • A custom MTA — Postfix is used as-is
  • Dovecot or a full mail stack for SASL — Cyrus SASL (sasldb2) only

The domain role ships in the current line (a global user plus domain users with assigned domains, outbound and inbound separately). The optional inbound relay (backup-MX / forwarder on port 25) ships in [1.4.0], off by default behind INBOUND_RELAY_ENABLE; it is relay/forward, not IMAP/webmail. Send-log retention in Settings ships in [1.5.0]. 30-day send statistics and auto level-2 rate limits ship in [1.6.0]. DMARC aggregate report ingest ships in [1.7.0], off by default behind DMARC_REPORTS_ENABLE. Items marked candidate in the roadmap require explicit approval before coding.


Multi-domain model

SelfPost is a multi-domain outbound relay. Two linked entities:

Sending domain

Example: example.com. Has its own DKIM key and selector.

Application (account)

A SASL login/password bound to one domain. A domain may have several applications (e.g. newsletter vs alerts), each with its own credentials, but each may send only from its own domain, never from another.

From-address mode (per application)

Set when creating or editing an application:

  1. Any address in the domain — *@example.com (wildcard in smtpd_sender_login_maps).
  2. Explicit address list — only listed From addresses within the domain; anything else is rejected even if it belongs to the same domain.

In both modes the From address must belong to the application's domain.

What the panel manages per domain

  • DKIM key + selector (shared by all applications on that domain)
  • One or more applications (SASL credentials + From mode + optional rate limits)
  • DNS guidance (DKIM TXT; reminders for SPF/DMARC)

Adding a domain does not create an application automatically.

Lifecycle

  • Add domain — record, DKIM key, DNS instructions; no application yet.
  • Add application — SASL pair (password shown once), From mode, map entries, postfix reload.
  • Delete domain — removes DKIM key and all its applications.
  • Delete application — removes only that app's SASL and map entries.

This is not multi-tenancy; it is one owner (or a small team with global and domain-scoped roles) operating several sending domains with independent application credentials.