mailglass_admin

Mountable LiveView dashboard for mailglass. The dev-preview surface at v0.1: see every mailable in your app, pick a scenario, edit the assigns inline, and inspect HTML / Text / Raw / Headers tabs — all without leaving the browser.

Installation

Add mailglass_admin to your adopter app's mix.exs:

def deps do
  [
    {:mailglass, "~> 0.1"},
    {:mailglass_admin, "~> 0.1", only: :dev}
  ]
end

Then mix deps.get.

Mount the preview

Add four lines to lib/my_app_web/router.ex:

import MailglassAdmin.Router

if Application.compile_env(:my_app, :dev_routes) do
  scope "/dev" do
    pipe_through :browser
    mailglass_admin_routes "/mail"
  end
end

Restart mix phx.server, visit /dev/mail. Done.

The if Application.compile_env(:my_app, :dev_routes) do ... end wrapper is the Phoenix 1.8 convention (same gate that protects live_dashboard and Plug.Swoosh.MailboxPreview). mailglass_admin does not check Mix.env() itself — dev-only is the adopter's responsibility.

LiveReload setup (optional)

When your adopter app runs under :phoenix_live_reload, mailglass_admin can refresh the preview automatically on file save. Add a live_reload.notify entry to your endpoint:

config :my_app, MyAppWeb.Endpoint,
  live_reload: [
    notify: [
      "mailglass:admin:reload": [~r"lib/.*mailer.*\.ex$"]
    ]
  ]

The topic is prefixed mailglass:admin:reload (not bare mailglass_admin_reload) to match the LINT-06 mailglass:-prefixed PubSub topic convention. When LiveReload is not configured the preview still works — the adopter just refreshes the browser manually.

preview_props/0 contract

Each Mailglass.Mailable module can declare preview scenarios by defining preview_props/0:

defmodule MyApp.UserMailer do
  use Mailglass.Mailable, stream: :transactional

  def preview_props do
    [
      welcome_default: %{user: %User{name: "Ada"}, team: %Team{name: "Analytical Engines"}},
      welcome_enterprise: %{user: %User{name: "Ada"}, team: %Team{name: "Analytical Engines"}, plan: :enterprise}
    ]
  end

  def welcome(assigns), do: ...
end

Each tuple is a discrete scenario; the sidebar nests scenarios under the mailable module name (MyApp.UserMailer -> welcome_default). Scenarios appear in insertion order. Mailables without preview_props/0 still show up in the sidebar as No previews defined — they remain discoverable even before you write any scenarios.

What this ships

• Auto-discovered mailable sidebar (collapsible scenario groups)
• Four tabs per scenario: HTML, Text, Raw (RFC 5322 envelope), Headers
• Type-inferred assigns form — edit any top-level assign inline and re-render
• Device toggle (375 / 768 / 1024) + chrome dark toggle
• Graceful failure badges for mailables whose preview_props/0 raises

What this does NOT ship

• Any prod-mountable admin surface (sent-mail inbox, event timeline, suppression UI). That lands at v0.5.
• Authentication or step-up protection. Dev-only mount relies on the adopter's :dev_routes wrapper — do not mount this in production.
• Search, filter, or pagination over mailables. v0.5.
• Inbound-mail (mailglass_inbound) Conductor LiveView — separate sibling package, v0.5+.

License

MIT. See LICENSE. Released alongside mailglass via coordinated linked-version Release Please tags.