Add Stripe-based billing system

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Jason Zimdars <jz@37signals.com>

saas/.kamal/secrets.beta

@@ -1,4 +1,4 @@
-SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Beta/RAILS_MASTER_KEY Beta/MYSQL_ALTER_PASSWORD Beta/MYSQL_ALTER_USER Beta/MYSQL_APP_PASSWORD Beta/MYSQL_APP_USER Beta/MYSQL_READONLY_PASSWORD Beta/MYSQL_READONLY_USER Beta/SECRET_KEY_BASE Beta/VAPID_PUBLIC_KEY Beta/VAPID_PRIVATE_KEY Beta/ACTIVE_STORAGE_ACCESS_KEY_ID Beta/ACTIVE_STORAGE_SECRET_ACCESS_KEY Beta/QUEENBEE_API_TOKEN Beta/SIGNAL_ID_SECRET Beta/SENTRY_DSN Beta/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Beta/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Beta/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT)
+SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Beta/RAILS_MASTER_KEY Beta/MYSQL_ALTER_PASSWORD Beta/MYSQL_ALTER_USER Beta/MYSQL_APP_PASSWORD Beta/MYSQL_APP_USER Beta/MYSQL_READONLY_PASSWORD Beta/MYSQL_READONLY_USER Beta/SECRET_KEY_BASE Beta/VAPID_PUBLIC_KEY Beta/VAPID_PRIVATE_KEY Beta/ACTIVE_STORAGE_ACCESS_KEY_ID Beta/ACTIVE_STORAGE_SECRET_ACCESS_KEY Beta/QUEENBEE_API_TOKEN Beta/SIGNAL_ID_SECRET Beta/SENTRY_DSN Beta/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Beta/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Beta/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT Beta/STRIPE_MONTHLY_V1_PRICE_ID Beta/STRIPE_SECRET_KEY Beta/STRIPE_WEBHOOK_SECRET)
 
 GITHUB_TOKEN=$(gh config get -h github.com oauth_token)
 BASECAMP_REGISTRY_PASSWORD=$(kamal secrets extract BASECAMP_REGISTRY_PASSWORD $SECRETS)
@@ -21,3 +21,6 @@ SENTRY_DSN=$(kamal secrets extract SENTRY_DSN $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT $SECRETS)
+STRIPE_MONTHLY_V1_PRICE_ID=$(kamal secrets extract STRIPE_MONTHLY_V1_PRICE_ID $SECRETS)
+STRIPE_SECRET_KEY=$(kamal secrets extract STRIPE_SECRET_KEY $SECRETS)
+STRIPE_WEBHOOK_SECRET=$(kamal secrets extract STRIPE_WEBHOOK_SECRET $SECRETS)

saas/.kamal/secrets.production

@@ -1,4 +1,4 @@
-SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Production/RAILS_MASTER_KEY Production/MYSQL_ALTER_PASSWORD Production/MYSQL_ALTER_USER Production/MYSQL_APP_PASSWORD Production/MYSQL_APP_USER Production/MYSQL_READONLY_PASSWORD Production/MYSQL_READONLY_USER Production/SECRET_KEY_BASE Production/VAPID_PUBLIC_KEY Production/VAPID_PRIVATE_KEY Production/ACTIVE_STORAGE_ACCESS_KEY_ID Production/ACTIVE_STORAGE_SECRET_ACCESS_KEY Production/QUEENBEE_API_TOKEN Production/SIGNAL_ID_SECRET Production/SENTRY_DSN Production/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Production/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Production/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT)
+SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Production/RAILS_MASTER_KEY Production/MYSQL_ALTER_PASSWORD Production/MYSQL_ALTER_USER Production/MYSQL_APP_PASSWORD Production/MYSQL_APP_USER Production/MYSQL_READONLY_PASSWORD Production/MYSQL_READONLY_USER Production/SECRET_KEY_BASE Production/VAPID_PUBLIC_KEY Production/VAPID_PRIVATE_KEY Production/ACTIVE_STORAGE_ACCESS_KEY_ID Production/ACTIVE_STORAGE_SECRET_ACCESS_KEY Production/QUEENBEE_API_TOKEN Production/SIGNAL_ID_SECRET Production/SENTRY_DSN Production/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Production/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Production/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT Production/STRIPE_MONTHLY_V1_PRICE_ID Production/STRIPE_SECRET_KEY Production/STRIPE_WEBHOOK_SECRET)
 
 GITHUB_TOKEN=$(gh config get -h github.com oauth_token)
 BASECAMP_REGISTRY_PASSWORD=$(kamal secrets extract BASECAMP_REGISTRY_PASSWORD $SECRETS)
@@ -21,3 +21,6 @@ SENTRY_DSN=$(kamal secrets extract SENTRY_DSN $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT $SECRETS)
+STRIPE_MONTHLY_V1_PRICE_ID=$(kamal secrets extract STRIPE_MONTHLY_V1_PRICE_ID $SECRETS)
+STRIPE_SECRET_KEY=$(kamal secrets extract STRIPE_SECRET_KEY $SECRETS)
+STRIPE_WEBHOOK_SECRET=$(kamal secrets extract STRIPE_WEBHOOK_SECRET $SECRETS)

saas/.kamal/secrets.staging

@@ -1,4 +1,4 @@
-SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Staging/RAILS_MASTER_KEY Staging/MYSQL_ALTER_PASSWORD Staging/MYSQL_ALTER_USER Staging/MYSQL_APP_PASSWORD Staging/MYSQL_APP_USER Staging/MYSQL_READONLY_PASSWORD Staging/MYSQL_READONLY_USER Staging/SECRET_KEY_BASE Staging/VAPID_PUBLIC_KEY Staging/VAPID_PRIVATE_KEY Staging/ACTIVE_STORAGE_ACCESS_KEY_ID Staging/ACTIVE_STORAGE_SECRET_ACCESS_KEY Staging/QUEENBEE_API_TOKEN Staging/SIGNAL_ID_SECRET Staging/SENTRY_DSN Staging/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Staging/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Staging/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT)
+SECRETS=$(kamal secrets fetch --adapter 1password --account basecamp --from Deploy/Fizzy Deployments/BASECAMP_REGISTRY_PASSWORD Deployments/DASH_BASIC_AUTH_SECRET Staging/RAILS_MASTER_KEY Staging/MYSQL_ALTER_PASSWORD Staging/MYSQL_ALTER_USER Staging/MYSQL_APP_PASSWORD Staging/MYSQL_APP_USER Staging/MYSQL_READONLY_PASSWORD Staging/MYSQL_READONLY_USER Staging/SECRET_KEY_BASE Staging/VAPID_PUBLIC_KEY Staging/VAPID_PRIVATE_KEY Staging/ACTIVE_STORAGE_ACCESS_KEY_ID Staging/ACTIVE_STORAGE_SECRET_ACCESS_KEY Staging/QUEENBEE_API_TOKEN Staging/SIGNAL_ID_SECRET Staging/SENTRY_DSN Staging/ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY Staging/ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY Staging/ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT Staging/STRIPE_MONTHLY_V1_PRICE_ID Staging/STRIPE_SECRET_KEY Staging/STRIPE_WEBHOOK_SECRET)
 
 GITHUB_TOKEN=$(gh config get -h github.com oauth_token)
 BASECAMP_REGISTRY_PASSWORD=$(kamal secrets extract BASECAMP_REGISTRY_PASSWORD $SECRETS)
@@ -21,3 +21,6 @@ SENTRY_DSN=$(kamal secrets extract SENTRY_DSN $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY $SECRETS)
 ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=$(kamal secrets extract ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT $SECRETS)
+STRIPE_MONTHLY_V1_PRICE_ID=$(kamal secrets extract STRIPE_MONTHLY_V1_PRICE_ID $SECRETS)
+STRIPE_SECRET_KEY=$(kamal secrets extract STRIPE_SECRET_KEY $SECRETS)
+STRIPE_WEBHOOK_SECRET=$(kamal secrets extract STRIPE_WEBHOOK_SECRET $SECRETS)

saas/app/assets/stylesheets/fizzy/saas.css

@@ -0,0 +1,64 @@
+/* Subscriptions
+/* ------------------------------------------------------------------------ */
+:root {
+  --settings-subscription-background: linear-gradient(to bottom, var(--color-canvas), oklch(var(--lch-violet-lighter)));
+  --settings-subscription-color: oklch(var(--lch-violet-medium));
+  --settings-subscription-text-color: oklch(var(--lch-violet-dark));
+
+  .settings-subscription__button {
+    --btn-background: var(--settings-subscription-color);
+    --btn-border-color: var(--color-canvas);
+    --btn-color: var(--color-canvas);
+    --focus-ring-color: var(--color-ink);
+  }
+
+  .settings-subscription__divider {
+    --divider-color: currentColor;
+
+    color: var(--settings-subscription-color);
+    margin-block-start: calc(var(--block-space-half) * -1);
+  }
+
+  .settings-subscription__footer {
+    color: var(--settings-subscription-text-color);
+
+    &::before {
+      content: "————";
+      display: block;
+      margin: auto;
+      text-align: center;
+    }
+  }
+
+  .settings-subscription__notch {
+    animation: wiggle 500ms ease;
+    background: var(--settings-subscription-background);
+    box-shadow: 0 0 0.3em 0.2em var(--settings-subscription-color);
+    border-radius: 3em;
+    color: var(--settings-subscription-text-color);
+    margin-inline: auto;
+    padding: 0 0.3em 0 1.2em;
+    transform: rotate(-1deg);
+
+    @media (max-width: 640px) {
+      padding-block: 0.6em;
+      padding-inline-start: 0.3em;
+    }
+
+    .btn {
+      margin-block: 0.3em;
+    }
+  }
+
+  .settings-subscription__panel {
+    background: var(--settings-subscription-background);
+  }
+
+  .settings_subscription__warning {
+    color: var(--settings-subscription-text-color);
+
+    a {
+      color: var(--settings-subscription-text-color);
+    }
+  }
+}

saas/app/assets/stylesheets/fizzy/saas/application.css

@@ -1,15 +0,0 @@
-/*
- * This is a manifest file that'll be compiled into application.css, which will include all the files
- * listed below.
- *
- * Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
- * or any plugin's vendor/assets/stylesheets directory can be referenced here using a relative path.
- *
- * You're free to add application-wide styles to this file and they'll appear at the bottom of the
- * compiled file so the styles you add here take precedence over styles defined in any other CSS/SCSS
- * files in this directory. Styles in this file should be added after the last require_* statement.
- * It is generally better to create a new file per style scope.
- *
- *= require_tree .
- *= require_self
- */

saas/app/controllers/account/billing_portals_controller.rb

@@ -0,0 +1,19 @@
+class Account::BillingPortalsController < ApplicationController
+  before_action :ensure_admin
+  before_action :ensure_subscribed_account
+
+  def show
+    redirect_to create_stripe_billing_portal_session.url, allow_other_host: true
+  end
+
+  private
+    def ensure_subscribed_account
+      unless Current.account.subscribed?
+        redirect_to account_subscription_path, alert: "No billing information found"
+      end
+    end
+
+    def create_stripe_billing_portal_session
+      Stripe::BillingPortal::Session.create(customer: Current.account.subscription.stripe_customer_id, return_url: account_settings_url)
+    end
+end

saas/app/controllers/account/subscriptions_controller.rb

@@ -0,0 +1,38 @@
+class Account::SubscriptionsController < ApplicationController
+  before_action :ensure_admin
+  before_action :set_stripe_session, only: :show
+
+  def show
+  end
+
+  def create
+    session = Stripe::Checkout::Session.create \
+      customer: find_or_create_stripe_customer,
+      mode: "subscription",
+      line_items: [ { price: Plan.paid.stripe_price_id, quantity: 1 } ],
+      success_url: account_subscription_url + "?session_id={CHECKOUT_SESSION_ID}",
+      cancel_url: account_subscription_url,
+      metadata: { account_id: Current.account.id, plan_key: Plan.paid.key }
+
+    redirect_to session.url, allow_other_host: true
+  end
+
+  private
+    def set_stripe_session
+      @session = Stripe::Checkout::Session.retrieve(params[:session_id]) if params[:session_id]
+    end
+
+    def find_or_create_stripe_customer
+      find_stripe_customer || create_stripe_customer
+    end
+
+    def find_stripe_customer
+      Stripe::Customer.retrieve(Current.account.subscription.stripe_customer_id) if Current.account.subscription&.stripe_customer_id
+    end
+
+    def create_stripe_customer
+      Stripe::Customer.create(email: Current.user.identity.email_address, name: Current.account.name, metadata: { account_id: Current.account.id }).tap do |customer|
+        Current.account.create_subscription!(stripe_customer_id: customer.id, plan_key: Plan.paid.key, status: "incomplete")
+      end
+    end
+end

saas/app/controllers/admin/account_searches_controller.rb

@@ -0,0 +1,5 @@
+class Admin::AccountSearchesController < AdminController
+  def create
+    redirect_to saas.edit_admin_account_path(params[:q])
+  end
+end

saas/app/controllers/admin/accounts_controller.rb

@@ -0,0 +1,25 @@
+class Admin::AccountsController < AdminController
+  layout "public"
+
+  before_action :set_account, only: %i[ edit update ]
+
+  def index
+  end
+
+  def edit
+  end
+
+  def update
+    @account.update!(account_params)
+    redirect_to saas.edit_admin_account_path(@account.external_account_id), notice: "Account updated"
+  end
+
+  private
+    def set_account
+      @account = Account.find_by!(external_account_id: params[:id])
+    end
+
+    def account_params
+      params.expect(account: [ :cards_count ])
+    end
+end

saas/app/controllers/admin/stats_controller.rb

@@ -0,0 +1,20 @@
+class Admin::StatsController < AdminController
+  layout "public"
+
+  def show
+    @accounts_total = Account.count
+    @accounts_last_7_days = Account.where(created_at: 7.days.ago..).count
+    @accounts_last_24_hours = Account.where(created_at: 24.hours.ago..).count
+
+    @identities_total = Identity.count
+    @identities_last_7_days = Identity.where(created_at: 7.days.ago..).count
+    @identities_last_24_hours = Identity.where(created_at: 24.hours.ago..).count
+
+    @top_accounts = Account
+      .where("cards_count > 0")
+      .order(cards_count: :desc)
+      .limit(20)
+
+    @recent_accounts = Account.order(created_at: :desc).limit(10)
+  end
+end

saas/app/controllers/concerns/card/limited.rb

@@ -0,0 +1,12 @@
+module Card::Limited
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :ensure_can_create_cards, only: %i[ create ]
+  end
+
+  private
+    def ensure_can_create_cards
+      head :forbidden if Current.account.exceeding_card_limit?
+    end
+end

saas/app/controllers/stripe/webhooks_controller.rb

@@ -0,0 +1,83 @@
+class Stripe::WebhooksController < ApplicationController
+  allow_unauthenticated_access
+  skip_before_action :require_account
+  skip_before_action :verify_authenticity_token
+
+  def create
+    event = verify_webhook_signature
+    return head :bad_request unless event
+
+    dispatch_stripe_event(event)
+
+    head :ok
+  end
+
+  private
+    def dispatch_stripe_event(event)
+      case event.type
+        when "checkout.session.completed"
+          handle_checkout_completed(event.data.object)
+        when "customer.subscription.updated"
+          handle_subscription_updated(event.data.object)
+        when "customer.subscription.deleted"
+          handle_subscription_deleted(event.data.object)
+        when "invoice.payment_failed"
+          handle_payment_failed(event.data.object)
+      end
+    end
+
+    def verify_webhook_signature
+      payload = request.body.read
+      sig_header = request.env["HTTP_STRIPE_SIGNATURE"]
+
+      Stripe::Webhook.construct_event(payload, sig_header, ENV["STRIPE_WEBHOOK_SECRET"])
+    rescue Stripe::SignatureVerificationError => e
+      Rails.logger.error "Stripe webhook signature verification failed: #{e.message}"
+      nil
+    end
+
+    def handle_checkout_completed(session)
+      return unless session.mode == "subscription"
+
+      subscription = find_subscription_by_customer(session.customer)
+      return unless subscription
+
+      stripe_subscription = Stripe::Subscription.retrieve(session.subscription)
+
+      subscription.update! \
+        stripe_subscription_id: stripe_subscription.id,
+        plan_key: session.metadata["plan_key"],
+        status: stripe_subscription.status,
+        current_period_end: extract_current_period_end(stripe_subscription)
+    end
+
+    def handle_subscription_updated(stripe_subscription)
+      if subscription = find_subscription_by_customer(stripe_subscription.customer)
+        subscription.update! \
+          status: stripe_subscription.status,
+          current_period_end: extract_current_period_end(stripe_subscription),
+          cancel_at: stripe_subscription.cancel_at ? Time.at(stripe_subscription.cancel_at) : nil
+      end
+    end
+
+    def handle_subscription_deleted(stripe_subscription)
+      if subscription = find_subscription_by_customer(stripe_subscription.customer)
+        subscription.update!(status: "canceled", stripe_subscription_id: nil)
+      end
+    end
+
+    def handle_payment_failed(invoice)
+      if subscription = find_subscription_by_customer(invoice.customer)
+        subscription.update!(status: "past_due")
+      end
+    end
+
+    def find_subscription_by_customer(customer_id)
+      Account::Subscription.find_by(stripe_customer_id: customer_id)
+    end
+
+    def extract_current_period_end(stripe_subscription)
+      timestamp = stripe_subscription.items.data.first&.current_period_end
+      Time.at(timestamp) if timestamp
+    end
+end

saas/app/helpers/subscriptions_helper.rb

@@ -0,0 +1,11 @@
+module SubscriptionsHelper
+  def subscription_period_end_action(subscription)
+    if subscription.to_be_canceled?
+      "Your Fizzy subscription ends on"
+    elsif subscription.canceled?
+      "Your Fizzy subscription ended on"
+    else
+      "Your next payment of <b>$#{ subscription.plan.price }</b> will be billed on".html_safe
+    end
+  end
+end

saas/app/models/account/billing.rb

@@ -0,0 +1,29 @@
+module Account::Billing
+  extend ActiveSupport::Concern
+
+  included do
+    has_one :subscription, class_name: "Account::Subscription", dependent: :destroy
+  end
+
+  NEAR_CARD_LIMIT_THRESHOLD = 100
+
+  def plan
+    active_subscription&.plan || Plan.free
+  end
+
+  def active_subscription
+    subscription if subscription&.active?
+  end
+
+  def subscribed?
+    subscription.present?
+  end
+
+  def nearing_plan_cards_limit?
+    plan.limit_cards? && (plan.card_limit - cards_count) < NEAR_CARD_LIMIT_THRESHOLD
+  end
+
+  def exceeding_card_limit?
+    cards_count > plan.card_limit
+  end
+end

saas/app/models/account/subscription.rb

@@ -0,0 +1,17 @@
+class Account::Subscription < SaasRecord
+  belongs_to :account
+
+  enum :status, %w[ active past_due unpaid canceled incomplete incomplete_expired trialing paused ].index_by(&:itself)
+
+  validates :plan_key, presence: true, inclusion: { in: Plan::PLANS.keys.map(&:to_s) }
+
+  delegate :paid?, to: :plan
+
+  def plan
+    Plan.find(plan_key)
+  end
+
+  def to_be_canceled?
+    active? && cancel_at.present?
+  end
+end

saas/app/models/plan.rb

@@ -0,0 +1,54 @@
+class Plan
+  PLANS = {
+    free_v1: { name: "Free", price: 0, card_limit: 1000, storage_limit: 1.gigabytes },
+    monthly_v1: { name: "Unlimitted", price: 20, card_limit: Float::INFINITY, storage_limit: 5.gigabytes, stripe_price_id: ENV.fetch("STRIPE_MONTHLY_V1_PRICE_ID", "price_1SaHykRwChFE4it8PePOdDpS") }
+  }
+
+  attr_reader :key, :name, :price, :card_limit, :storage_limit, :stripe_price_id
+
+  class << self
+    def all
+      @all ||= PLANS.map { |key, properties| new(key: key, **properties) }
+    end
+
+    def free
+      @free ||= all.find(&:free?)
+    end
+
+    def paid
+      @paid ||= all.find(&:paid?)
+    end
+
+    def find(key)
+      @all_by_key ||= all.index_by(&:key).with_indifferent_access
+      @all_by_key[key]
+    end
+
+    alias [] find
+  end
+
+  def initialize(key:, name:, price:, card_limit:, storage_limit:, stripe_price_id: nil)
+    @key = key
+    @name = name
+    @price = price
+    @card_limit = card_limit
+    @storage_limit = storage_limit
+    @stripe_price_id = stripe_price_id
+  end
+
+  def free?
+    price.zero?
+  end
+
+  def paid?
+    !free?
+  end
+
+  def limit_cards?
+    card_limit != Float::INFINITY
+  end
+
+  def formatted_storage_limit
+    ActionController::Base.helpers.number_to_human_size(storage_limit).delete(" ")
+  end
+end

saas/app/views/account/settings/_subscription.html.erb

@@ -0,0 +1,7 @@
+<p hidden>Status: <strong><%= subscription.status.titleize %></strong></p>
+
+<% if subscription.current_period_end %>
+  <p class="txt-medium margin-none-block-start"><%= subscription_period_end_action(subscription) %> <strong><%= subscription.current_period_end.to_date.to_fs(:long) %></strong></p>
+<% end %>
+
+<%= link_to "Manage Billing", account_billing_portal_path, class: "btn", data: { turbo_prefetch: false } %>

saas/app/views/account/settings/_subscription_panel.html.erb

@@ -0,0 +1,28 @@
+<% if Current.user.admin? %>
+  <section class="panel panel--wide settings-subscription__panel shadow center margin-block-double">
+    <h2 id="subscription" class="divider settings-subscription__divider txt-small txt-uppercase margin-none">Subscription</h2>
+
+    <% if Current.account.plan.free? %>
+      <% if Current.account.exceeding_card_limit? %>
+        <h3 class="margin-block-start margin-block-end-half txt-large font-weight-black">You've used up your <u><%= Plan.free.card_limit %></u> free cards</h3>
+      <% else %>
+        <h3 class="margin-block-start margin-block-end-half txt-large font-weight-black">You've used <u><%= Current.account.cards_count %></u> free cards out of <%= Plan.free.card_limit %></h3>
+      <% end %>
+
+      <p class="margin-none-block-start">If you'd like to keep using Fizzy past <%= Plan.free.card_limit %> cards, it's only <strong>$<%= Plan.paid.price %>/month</strong> for <strong>unlimited cards</strong> + <strong>unlimited users</strong>. You'll also get <strong><%= number_to_human_size(Plan.paid.formatted_storage_limit) %></strong> of storage. </p>
+
+      <%= button_to "Upgrade to #{Plan.paid.name} fo $#{ Plan.paid.price }/month", account_subscription_path, class: "btn settings-subscription__button txt-medium", form: { data: { turbo: false } } %>
+
+      <p>Cancel any time, no contracts, take your data with you whenever.</p>
+      <p class="settings-subscription__footer txt-small margin-none-block-end">Right now you're on the <strong><%= Current.account.plan.name %></strong> plan which includes <%= Plan.free.card_limit %> cards, unlimitted users, and <%= number_to_human_size(Plan.free.formatted_storage_limit) %> of storage.</p>
+    <% else %>
+      <h3 class="margin-block-start margin-block-end-half txt-x-large font-weight-black">Thank you for buying Fizzy</h3>
+
+      <% if Current.account.subscription %>
+        <%= render "account/settings/subscription", subscription: Current.account.subscription %>
+        <p class="settings-subscription__footer txt-small">Right now you're on the <strong><%= Current.account.plan.name %></strong> plan which includes unlimitted cards, unlimitted users, and <%= number_to_human_size(Plan.paid.formatted_storage_limit) %> of storage.</p>
+      <% end %>
+    <% end %>
+
+  </section>
+<% end %>

saas/app/views/account/subscriptions/_upgrade.html.erb

@@ -0,0 +1,6 @@
+<div class="settings-subscription__notch card-perma__notch card-perma__notch--bottom">
+  <strong>You've used your <u><%= Plan.free.card_limit %></u> free cards.</strong>
+  <%= link_to account_settings_path(anchor: "subscription"), class: "btn settings-subscription__button" do %>
+    <span>Upgrade to Unlimitted</span>
+  <% end %>
+</div>

saas/app/views/account/subscriptions/show.html.erb

@@ -0,0 +1,9 @@
+<% @page_title = "Thank you" %>
+
+<% if @session&.payment_status == "paid" %>
+  <section class="panel panel--centered center borderless">
+    <h1 class="txt-x-large font-weight-black margin-none">Thanks for buying Fizzy!</h1>
+    <p class="txt-medium margin-none-block-start">Your payment was successful. You're now on the <strong><%= Current.account.plan.name %></strong> plan.</p>
+    <%= link_to "Done", account_settings_path, class: "btn settings-subscription__button txt-medium" %>
+  </section>
+<% end %>

saas/app/views/admin/accounts/edit.html.erb

@@ -0,0 +1,14 @@
+<h1>Edit Account <%= @account.external_account_id %></h1>
+
+<p><strong>Name:</strong> <%= @account.name %></p>
+
+<%= form_with model: @account, url: saas.admin_account_path(@account.external_account_id) do |form| %>
+  <p>
+    <%= form.label :cards_count %>
+    <%= form.number_field :cards_count %>
+  </p>
+
+  <%= form.submit "Update" %>
+<% end %>
+
+<p><%= link_to "Back", saas.admin_accounts_path %></p>

saas/app/views/admin/accounts/index.html.erb

@@ -0,0 +1,6 @@
+<h1>Find Account</h1>
+
+<%= form_with url: saas.admin_account_search_path do |form| %>
+  <%= form.text_field :q, placeholder: "Account ID", autofocus: true %>
+  <%= form.submit "Search" %>
+<% end %>

saas/app/views/admin/stats/show.html.erb

@@ -0,0 +1,126 @@
+<% @page_title = "Account Statistics" %>
+
+<% content_for :header do %>
+  <h1 class="header__title"><%= @page_title %></h1>
+<% end %>
+
+<section class="settings">
+  <div class="settings__panel panel shadow center">
+    <div class="flex flex-column gap margin-block-half">
+      <div class="flex flex-column gap-half">
+        <header>
+          <h2 class="divider txt-medium margin-block-start">Accounts Created</h2>
+        </header>
+        <div class="flex gap-half">
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">Total</div>
+            <div class="txt-large">
+              <strong><%= @accounts_total %></strong>
+            </div>
+          </div>
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">7 days</div>
+            <div class="txt-large">
+              <strong><%= @accounts_last_7_days %></strong>
+            </div>
+          </div>
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">24 hours</div>
+            <div class="txt-large">
+              <strong><%= @accounts_last_24_hours %></strong>
+            </div>
+          </div>
+        </div>
+      </div>
+
+      <div class="flex flex-column gap-half">
+        <header>
+          <h2 class="divider txt-medium margin-block-start">Identities Created</h2>
+        </header>
+        <div class="flex gap-half">
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">Total</div>
+            <div class="txt-large">
+              <strong><%= @identities_total %></strong>
+            </div>
+          </div>
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">7 days</div>
+            <div class="txt-large">
+              <strong><%= @identities_last_7_days %></strong>
+            </div>
+          </div>
+          <div class="flex flex-column gap-quarter flex-item-grow">
+            <div class="txt-x-small">24 hours</div>
+            <div class="txt-large">
+              <strong><%= @identities_last_24_hours %></strong>
+            </div>
+          </div>
+        </div>
+      </div>
+    </div>
+  </div>
+
+  <div class="settings__panel panel shadow center">
+    <header>
+      <h2 class="divider txt-medium margin-block-start">
+        10 Most Recent Signups
+      </h2>
+    </header>
+
+    <ul class="margin-block-half">
+      <% @recent_accounts.each do |account| %>
+        <% admin_user = account.users.owner.first %>
+        <li class="flex align-start gap-half margin-block-start-half">
+          <div
+            class="flex-item-grow min-width overflow-ellipsis"
+            style="text-align: left"
+          >
+            <strong><%= account.name %></strong>
+            <br>
+            <span class="txt-x-small txt-ink-medium">
+              #<%= account.external_account_id %> •
+              <%= admin_user&.identity&.email_address || "No admin" %>
+            </span>
+          </div>
+
+          <div class="txt-medium txt-ink-medium" style="text-align: right">
+            <%= time_ago_in_words(account.created_at) %> ago
+          </div>
+        </li>
+      <% end %>
+    </ul>
+  </div>
+
+  <div class="settings__panel panel shadow center">
+    <header>
+      <h2 class="divider txt-medium margin-block-start">
+        Top 20 Accounts by Card Count
+      </h2>
+    </header>
+
+    <ul class="margin-block-half">
+      <% @top_accounts.each do |account| %>
+        <% admin_user = account.users.owner.first %>
+        <li class="flex align-start gap-half margin-block-start-half">
+          <div
+            class="flex-item-grow min-width overflow-ellipsis"
+            style="text-align: left"
+          >
+            <strong><%= account.name %></strong>
+            <br>
+            <span class="txt-x-small txt-ink-medium">
+              #<%= account.external_account_id %> •
+              <%= admin_user&.identity&.email_address || "No admin" %>
+            </span>
+          </div>
+
+          <div class="txt-medium">
+            <strong><%= number_with_delimiter(account.cards_count) %></strong>
+            <span class="txt-x-small txt-ink-medium">cards</span>
+          </div>
+        </li>
+      <% end %>
+    </ul>
+  </div>
+</section>

saas/app/views/cards/container/footer/saas/_create.html.erb

@@ -0,0 +1,5 @@
+<% if Current.account.exceeding_card_limit? %>
+  <%= render "account/subscriptions/upgrade" %>
+<% else %>
+  <%= render "cards/container/footer/create", card: card %>
+<% end %>

saas/app/views/cards/container/footer/saas/_near_notice.html.erb

@@ -0,0 +1,5 @@
+<% if Current.account.nearing_plan_cards_limit? %>
+  <div class="settings_subscription__warning full-width pad-inline center margin-block-half">
+    You've used <%= Current.account.cards_count %> out of <%= Plan.free.card_limit %> free cards. <strong><%= link_to "Upgrade to unlimitted", account_settings_path(anchor: "subscription") %></strong>.
+  </div>
+<% end %>

saas/config/deploy.beta.yml

@@ -44,6 +44,9 @@ env:
     - ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY
     - ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY
     - ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT
+    - STRIPE_MONTHLY_V1_PRICE_ID
+    - STRIPE_SECRET_KEY
+    - STRIPE_WEBHOOK_SECRET
   tags:
     sc_chi: {}
     df_iad:

saas/config/deploy.production.yml

@@ -50,6 +50,9 @@ env:
     - ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY
     - ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY
     - ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT
+    - STRIPE_MONTHLY_V1_PRICE_ID
+    - STRIPE_SECRET_KEY
+    - STRIPE_WEBHOOK_SECRET
   tags:
     sc_chi:
       MYSQL_SOLID_CACHE_HOST: fizzy-solidcache-db-01.sc-chi-int.37signals.com

saas/config/deploy.staging.yml

@@ -50,6 +50,9 @@ env:
     - ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY
     - ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY
     - ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT
+    - STRIPE_MONTHLY_V1_PRICE_ID
+    - STRIPE_SECRET_KEY
+    - STRIPE_WEBHOOK_SECRET
   tags:
     sc_chi:
       MYSQL_SOLID_CACHE_HOST: fizzy-staging-solidcache-db-01.sc-chi-int.37signals.com

saas/config/routes.rb

@@ -3,5 +3,8 @@ Fizzy::Saas::Engine.routes.draw do
 
   namespace :admin do
     mount Audits1984::Engine, at: "/console"
+    get "stats", to: "stats#show"
+    resource :account_search, only: :create
+    resources :accounts
   end
 end

saas/db/migrate/20251203144630_create_account_subscriptions.rb

@@ -0,0 +1,15 @@
+class CreateAccountSubscriptions < ActiveRecord::Migration[8.2]
+  def change
+    create_table :account_subscriptions, id: :uuid do |t|
+      t.references :account, null: false, type: :uuid, index: true
+      t.string :plan_key
+      t.string :stripe_customer_id, null: false, index: { unique: true }
+      t.string :stripe_subscription_id, index: { unique: true }
+      t.string :status
+      t.datetime :current_period_end
+      t.datetime :cancel_at
+
+      t.timestamps
+    end
+  end
+end

saas/db/saas_schema.rb

@@ -10,7 +10,22 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.2].define(version: 2025_12_02_205753) do
+ActiveRecord::Schema[8.2].define(version: 2025_12_03_144630) do
+  create_table "account_subscriptions", id: :uuid, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.uuid "account_id", null: false
+    t.datetime "cancel_at"
+    t.datetime "created_at", null: false
+    t.datetime "current_period_end"
+    t.string "plan_key"
+    t.string "status"
+    t.string "stripe_customer_id", null: false
+    t.string "stripe_subscription_id"
+    t.datetime "updated_at", null: false
+    t.index ["account_id"], name: "index_account_subscriptions_on_account_id"
+    t.index ["stripe_customer_id"], name: "index_account_subscriptions_on_stripe_customer_id", unique: true
+    t.index ["stripe_subscription_id"], name: "index_account_subscriptions_on_stripe_subscription_id", unique: true
+  end
+
   create_table "audits1984_audits", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.uuid "auditor_id", null: false
     t.datetime "created_at", null: false

saas/fizzy-saas.gemspec

@@ -18,7 +18,7 @@ Gem::Specification.new do |spec|
   spec.metadata["source_code_uri"] = "https://github.com/basecamp/fizzy-saas"
 
   spec.files = Dir.chdir(File.expand_path(__dir__)) do
-    Dir["{app,config,db,lib,test}/**/*", "LICENSE.md", "Rakefile", "README.md"]
+    Dir["{app,config,db,lib}/**/*", "test/fixtures/**/*", "LICENSE.md", "Rakefile", "README.md"]
   end
 
   spec.add_dependency "rails", ">= 8.1.0.beta1"

saas/lib/fizzy/saas/engine.rb

@@ -9,6 +9,28 @@ module Fizzy
       # moved from config/initializers/queenbee.rb
       Queenbee.host_app = Fizzy
 
+      initializer "fizzy_saas.content_security_policy", before: :load_config_initializers do |app|
+        app.config.x.content_security_policy.form_action = "https://checkout.stripe.com"
+      end
+
+      initializer "fizzy_saas.assets" do |app|
+        app.config.assets.paths << root.join("app/assets/stylesheets")
+      end
+
+      initializer "fizzy.saas.routes", after: :add_routing_paths do |app|
+        # Routes that rely on the implicit account tenant should go here instead of in +routes.rb+.
+        app.routes.prepend do
+          namespace :account do
+            resource :billing_portal, only: :show
+            resource :subscription
+          end
+
+          namespace :stripe do
+            resource :webhooks, only: :create
+          end
+        end
+      end
+
       initializer "fizzy.saas.mount" do |app|
         app.routes.append do
           mount Fizzy::Saas::Engine => "/", as: "saas"
@@ -47,6 +69,10 @@ module Fizzy
         end
       end
 
+      initializer "fizzy_saas.stripe" do
+        Stripe.api_key = ENV["STRIPE_SECRET_KEY"]
+      end
+
       initializer "fizzy_saas.sentry" do
         if !Rails.env.local? && ENV["SKIP_TELEMETRY"].blank?
           Sentry.init do |config|
@@ -101,6 +127,8 @@ module Fizzy
       end
 
       config.to_prepare do
+        ::Account.include(Account::Billing)
+        ::CardsController.include(Card::Limited)
         ::Signup.prepend(Fizzy::Saas::Signup)
 
         Queenbee::Subscription.short_names = Subscription::SHORT_NAMES

saas/lib/fizzy/saas/testing.rb

@@ -7,3 +7,14 @@ Queenbee::Remote::Account.class_eval do
     super + Random.rand(1000000)
   end
 end
+
+# Add engine fixtures to the test fixture paths
+module Fizzy::Saas::EngineFixtures
+  def included(base)
+    super
+    engine_fixtures = Fizzy::Saas::Engine.root.join("test", "fixtures").to_s
+    base.fixture_paths << engine_fixtures unless base.fixture_paths.include?(engine_fixtures)
+  end
+end
+
+ActiveRecord::TestFixtures.singleton_class.prepend(Fizzy::Saas::EngineFixtures)

saas/test/controllers/accounts/billing_portals_controller_test.rb

@@ -0,0 +1,29 @@
+require "test_helper"
+require "ostruct"
+
+class Account::BillingPortalsControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in_as :kevin
+  end
+
+  test "redirects to stripe billing portal" do
+    Current.account.subscription.update!(stripe_customer_id: "cus_test123")
+
+    session = OpenStruct.new(url: "https://billing.stripe.com/session123")
+    Stripe::BillingPortal::Session.expects(:create)
+      .with(customer: "cus_test123", return_url: account_settings_url)
+      .returns(session)
+
+    get account_billing_portal_path
+
+    assert_redirected_to "https://billing.stripe.com/session123"
+  end
+
+  test "requires admin" do
+    logout_and_sign_in_as :david
+
+    get account_billing_portal_path
+
+    assert_response :forbidden
+  end
+end

saas/test/controllers/accounts/subscriptions_controller_test.rb

@@ -0,0 +1,47 @@
+require "test_helper"
+require "ostruct"
+
+class Account::SubscriptionsControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    sign_in_as :kevin
+  end
+
+  test "show" do
+    get account_subscription_path
+    assert_response :success
+  end
+
+  test "show with session_id retrieves stripe session" do
+    Stripe::Checkout::Session.stubs(:retrieve).with("sess_123").returns(OpenStruct.new(id: "sess_123"))
+
+    get account_subscription_path(session_id: "sess_123")
+    assert_response :success
+  end
+
+  test "show requires admin" do
+    logout_and_sign_in_as :david
+
+    get account_subscription_path
+    assert_response :forbidden
+  end
+
+  test "create redirects to stripe checkout" do
+    customer = OpenStruct.new(id: "cus_test_37signals")
+    session = OpenStruct.new(url: "https://checkout.stripe.com/session123")
+
+    Stripe::Customer.stubs(:retrieve).returns(customer)
+    Stripe::Checkout::Session.stubs(:create).returns(session)
+
+    post account_subscription_path
+
+    assert_redirected_to "https://checkout.stripe.com/session123"
+  end
+
+  test "create requires admin" do
+    logout_and_sign_in_as :david
+
+    post account_subscription_path
+    assert_response :forbidden
+  end
+
+end

saas/test/controllers/admin/accounts_controller_test.rb

@@ -0,0 +1,58 @@
+require "test_helper"
+
+class Admin::AccountsControllerTest < ActionDispatch::IntegrationTest
+  def saas
+    Fizzy::Saas::Engine.routes.url_helpers
+  end
+
+  test "staff can access index" do
+    sign_in_as :david
+
+    untenanted do
+      get saas.admin_accounts_path
+    end
+
+    assert_response :success
+  end
+
+  test "search account" do
+    sign_in_as :david
+
+    untenanted do
+      post saas.admin_account_search_path, params: { q: accounts(:"37s").external_account_id }
+      assert_redirected_to saas.edit_admin_account_path(accounts(:"37s").external_account_id)
+    end
+  end
+
+  test "staff can edit account" do
+    sign_in_as :david
+
+    untenanted do
+      get saas.edit_admin_account_path(accounts(:"37s").external_account_id)
+    end
+
+    assert_response :success
+  end
+
+  test "staff can update cards_count" do
+    sign_in_as :david
+
+    untenanted do
+      patch saas.admin_account_path(accounts(:"37s").external_account_id), params: { account: { cards_count: 500 } }
+      assert_redirected_to saas.edit_admin_account_path(accounts(:"37s").external_account_id)
+    end
+
+    assert_equal 500, accounts(:"37s").reload.cards_count
+  end
+
+  test "non-staff cannot access accounts" do
+    sign_in_as :jz
+
+    untenanted do
+      patch saas.admin_account_path(accounts(:"37s").external_account_id), params: { account: { cards_count: 9999 } }
+    end
+
+    assert_response :forbidden
+    assert_not_equal 9999, accounts(:"37s").reload.cards_count
+  end
+end

saas/test/controllers/admin/stats_controller_test.rb

@@ -0,0 +1,27 @@
+require "test_helper"
+
+class Admin::StatsControllerTest < ActionDispatch::IntegrationTest
+  def saas
+    Fizzy::Saas::Engine.routes.url_helpers
+  end
+
+  test "staff can access stats" do
+    sign_in_as :david
+
+    untenanted do
+      get saas.admin_stats_path
+    end
+
+    assert_response :success
+  end
+
+  test "non-staff cannot access stats" do
+    sign_in_as :jz
+
+    untenanted do
+      get saas.admin_stats_path
+    end
+
+    assert_response :forbidden
+  end
+end

saas/test/controllers/card/limited_test.rb

@@ -0,0 +1,15 @@
+require "test_helper"
+
+class Card::LimitedTest < ActionDispatch::IntegrationTest
+  test "cannot create cards when card limit exceeded" do
+    sign_in_as :mike
+
+    accounts(:initech).update_column(:cards_count, 1001)
+
+    assert_no_difference -> { Card.count } do
+      post board_cards_path(boards(:miltons_wish_list), script_name: accounts(:initech).slug)
+    end
+
+    assert_response :forbidden
+  end
+end

saas/test/controllers/stripe/webhooks_controller_test.rb

@@ -0,0 +1,95 @@
+require "test_helper"
+require "ostruct"
+
+class Stripe::WebhooksControllerTest < ActionDispatch::IntegrationTest
+  setup do
+    @account = Account.create!(name: "Test")
+    @subscription = @account.create_subscription! \
+      plan_key: "monthly_v1",
+      status: "incomplete",
+      stripe_customer_id: "cus_test123"
+  end
+
+  test "invalid signature returns bad request" do
+    Stripe::Webhook.stubs(:construct_event).raises(Stripe::SignatureVerificationError.new("invalid", "sig"))
+
+    post stripe_webhooks_path
+    assert_response :bad_request
+  end
+
+  test "checkout session completed activates subscription" do
+    stripe_sub = OpenStruct.new(id: "sub_123", status: "active", items: stub_items(1.month.from_now.to_i))
+
+    event = stripe_event("checkout.session.completed",
+      mode: "subscription",
+      customer: "cus_test123",
+      subscription: "sub_123",
+      metadata: { "plan_key" => "monthly_v1" }
+    )
+
+    Stripe::Webhook.stubs(:construct_event).returns(event)
+    Stripe::Subscription.stubs(:retrieve).returns(stripe_sub)
+
+    post stripe_webhooks_path
+
+    assert_response :ok
+    @subscription.reload
+    assert_equal "sub_123", @subscription.stripe_subscription_id
+    assert_equal "active", @subscription.status
+  end
+
+  test "subscription updated changes status" do
+    @subscription.update!(stripe_subscription_id: "sub_123", status: "active")
+
+    event = stripe_event("customer.subscription.updated",
+      customer: "cus_test123",
+      status: "past_due",
+      cancel_at: nil,
+      items: stub_items(1.month.from_now.to_i)
+    )
+
+    Stripe::Webhook.stubs(:construct_event).returns(event)
+
+    post stripe_webhooks_path
+
+    assert_response :ok
+    assert_equal "past_due", @subscription.reload.status
+  end
+
+  test "subscription deleted cancels subscription" do
+    @subscription.update!(stripe_subscription_id: "sub_123", status: "active")
+
+    event = stripe_event("customer.subscription.deleted", customer: "cus_test123")
+
+    Stripe::Webhook.stubs(:construct_event).returns(event)
+
+    post stripe_webhooks_path
+
+    assert_response :ok
+    @subscription.reload
+    assert_equal "canceled", @subscription.status
+    assert_nil @subscription.stripe_subscription_id
+  end
+
+  test "payment failed marks subscription as past due" do
+    @subscription.update!(stripe_subscription_id: "sub_123", status: "active")
+
+    event = stripe_event("invoice.payment_failed", customer: "cus_test123")
+
+    Stripe::Webhook.stubs(:construct_event).returns(event)
+
+    post stripe_webhooks_path
+
+    assert_response :ok
+    assert_equal "past_due", @subscription.reload.status
+  end
+
+  private
+    def stripe_event(type, **attributes)
+      OpenStruct.new(type: type, data: OpenStruct.new(object: OpenStruct.new(attributes)))
+    end
+
+    def stub_items(current_period_end)
+      OpenStruct.new(data: [ OpenStruct.new(current_period_end: current_period_end) ])
+    end
+end

saas/test/fixtures/account_subscriptions.yml

@@ -0,0 +1,11 @@
+_fixture:
+  model_class: Account::Subscription
+
+signals_monthly:
+  id: <%= ActiveRecord::FixtureSet.identify("signals_monthly", :uuid) %>
+  account_id: <%= ActiveRecord::FixtureSet.identify("37s", :uuid) %>
+  plan_key: monthly_v1
+  status: active
+  stripe_customer_id: cus_test_37signals
+  created_at: <%= Time.current %>
+  updated_at: <%= Time.current %>

saas/test/models/account/billing_test.rb

@@ -0,0 +1,49 @@
+require "test_helper"
+
+class Account::BillingTest < ActiveSupport::TestCase
+  test "active subscription" do
+    account = Account.create!(name: "Test")
+
+    # No subscription
+    assert_nil account.active_subscription
+
+    # Subscription but it is not active
+    account.create_subscription!(plan_key: "monthly_v1", status: "canceled", stripe_customer_id: "cus_test")
+    assert_nil account.active_subscription
+
+    # Active subscription exists
+    account.subscription.update!(status: "active")
+    assert_equal account.subscription, account.active_subscription
+  end
+
+  test "detect nearing card limit" do
+    # Paid plans are never limited
+    accounts(:"37s").update_column(:cards_count, 1_000_000)
+    assert_not accounts(:"37s").nearing_plan_cards_limit?
+
+    # Free plan not near limit
+    accounts(:initech).update_column(:cards_count, 899)
+    assert_not accounts(:initech).nearing_plan_cards_limit?
+
+    # Free plan near limit
+    accounts(:initech).update_column(:cards_count, 900)
+    assert_not accounts(:initech).nearing_plan_cards_limit?
+
+    accounts(:initech).update_column(:cards_count, 901)
+    assert accounts(:initech).nearing_plan_cards_limit?
+  end
+
+  test "detect exceeding card limit" do
+    # Paid plans are never limited
+    accounts(:"37s").update_column(:cards_count, 1_000_000)
+    assert_not accounts(:"37s").exceeding_card_limit?
+
+    # Free plan under limit
+    accounts(:initech).update_column(:cards_count, 999)
+    assert_not accounts(:initech).exceeding_card_limit?
+
+    # Free plan over limit
+    accounts(:initech).update_column(:cards_count, 1001)
+    assert accounts(:initech).exceeding_card_limit?
+  end
+end

saas/test/models/account/subscription_test.rb

@@ -0,0 +1,18 @@
+require "test_helper"
+
+class Account::SubscriptionTest < ActiveSupport::TestCase
+  test "get the account plan" do
+    subscription = Account::Subscription.new(plan_key: "free_v1")
+    assert_equal Plan[:free_v1], subscription.plan
+  end
+
+  test "check if account is active" do
+    subscription = Account::Subscription.new(status: "active")
+    assert subscription.active?
+  end
+
+  test "check if account is paid" do
+    assert Account::Subscription.new(plan_key: "monthly_v1", status: "active").paid?
+    assert_not Account::Subscription.new(plan_key: "free_v1", status: "active").paid?
+  end
+end

saas/test/models/plan_test.rb

@@ -0,0 +1,11 @@
+require "test_helper"
+
+class PlanTest < ActiveSupport::TestCase
+  test "free plan is free" do
+    assert Plan[:free_v1].free?
+  end
+
+  test "monthly plan is not free" do
+    assert_not Plan[:monthly_v1].free?
+  end
+end