diff --git a/app/controllers/concerns/authentication.rb b/app/controllers/concerns/authentication.rb
index d47dc44d2..dc75fb777 100644
--- a/app/controllers/concerns/authentication.rb
+++ b/app/controllers/concerns/authentication.rb
@@ -19,6 +19,7 @@ module Authentication
     end
 
     def require_untenanted_access(**options)
+      skip_before_action :set_current_account, **options
       skip_before_action :require_authentication, **options
       before_action :redirect_tenanted_request, **options
     end
diff --git a/app/controllers/signup/accounts_controller.rb b/app/controllers/signup/accounts_controller.rb
new file mode 100644
index 000000000..e722684ea
--- /dev/null
+++ b/app/controllers/signup/accounts_controller.rb
@@ -0,0 +1,27 @@
+class Signup::AccountsController < ApplicationController
+  require_untenanted_access
+
+  def new
+    @signup = Signup.new
+  end
+
+  def create
+    @signup = Signup.new(signup_params)
+
+    if @signup.process
+      redirect_to_account(@signup.account)
+    else
+      render :new, status: :unprocessable_entity
+    end
+  end
+
+  private
+    def signup_params
+      params.require(:signup).permit(:full_name, :email_address, :password, :company_name)
+    end
+
+    def redirect_to_account(account)
+      redirect_to account.signal_account.owner.remote_login_url(proceed_to: root_path),
+                  allow_other_host: true
+    end
+end
diff --git a/app/views/signup/accounts/new.html.erb b/app/views/signup/accounts/new.html.erb
new file mode 100644
index 000000000..9f69eba4b
--- /dev/null
+++ b/app/views/signup/accounts/new.html.erb
@@ -0,0 +1,58 @@
+<% @page_title = "Sign up for Fizzy" %>
+
+<div class="panel shadow center margin-block-double <%= "shake" if flash[:alert] %>" style="--panel-size: 65ch;">
+  <h1 class="txt-xx-large margin-block-end-double">Fizzy</h1>
+  <h2 class="txt-large margin-block-end-double">Create your account</h2>
+
+  <%= form_with model: @signup, url: signup_accounts_path, scope: "signup", class: "flex flex-column gap txt-large", data: { turbo: false } do |form| %>
+    <div class="flex align-center gap">
+      <label class="flex align-center gap input input--actor txt-large">
+        <%= form.text_field :full_name, class: "input", autocomplete: "name", placeholder: "Your name", autofocus: true, required: true %>
+        <%= icon_tag "person", class: "txt-large" %>
+      </label>
+    </div>
+
+    <div class="flex align-center gap">
+      <label class="flex align-center gap input input--actor txt-large">
+        <%= form.email_field :email_address, class: "input", autocomplete: "username", placeholder: "Your email address", required: true %>
+        <%= icon_tag "email", class: "txt-large" %>
+      </label>
+    </div>
+
+    <div class="flex align-center gap">
+      <label class="flex align-center gap input input--actor txt-large">
+        <%= form.text_field :company_name, class: "input", autocomplete: "organization", placeholder: "Your organization's name", required: true %>
+        <%= icon_tag "building", class: "txt-large" %>
+      </label>
+    </div>
+
+    <div class="flex align-center gap">
+      <label class="flex align-center gap input input--actor txt-large">
+        <%= form.password_field :password, class: "input", autocomplete: "new-password", placeholder: "Password (at least 12 characters)", required: true, maxlength: 72, minlength: 12 %>
+        <%= icon_tag "password", class: "txt-large" %>
+      </label>
+    </div>
+
+    <% if @signup.errors.any? %>
+      <div class="alert alert--error">
+        <ul class="margin-block-none">
+          <% @signup.errors.full_messages.each do |message| %>
+            <li><%= message %></li>
+          <% end %>
+        </ul>
+      </div>
+    <% end %>
+
+    <button type="submit" class="btn btn--reversed center">
+      <%= icon_tag "arrow-right" %>
+      <span>Create your account</span>
+    </button>
+  <% end %>
+
+  <footer class="margin-block-start-double txt-center">
+    <p class="txt-small txt-muted">
+      Already have an account? 
+      <%= link_to "Sign in", Launchpad.login_url(product: true), class: "decorated" %>
+    </p>
+  </footer>
+</div>
diff --git a/config/initializers/tenanting.rb b/config/initializers/tenanting.rb
index 78e5d8e05..ce4193330 100644
--- a/config/initializers/tenanting.rb
+++ b/config/initializers/tenanting.rb
@@ -2,10 +2,17 @@ Rails.application.config.after_initialize do
   # in production and staging, we're using a two-level subdomain like "tenant.fizzy.37signals.com".
   # in development and beta it's only a single-level subdomain.
   Rails.application.config.active_record_tenanted.tenant_resolver = ->(request) do
-    next nil if request.path == "/up"
-
     tld_length = [ "37signals.com", "37signals-staging.com" ].include?(request.domain) ? 2 : 1
-    request.subdomain(tld_length).presence || "return-404" # this is a quick fix for now
+
+    if request.path == "/up"
+      nil
+    elsif subdomain = request.subdomain(tld_length).presence
+      subdomain
+    elsif optional = request.path =~ %r{^/signup\b}
+      nil
+    else
+      "return-404" # this is a quick fix for now
+    end
   end
 end
 
diff --git a/config/routes.rb b/config/routes.rb
index 7cf104da4..ad780b0da 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -88,6 +88,11 @@ Rails.application.routes.draw do
     get "launchpad", to: "sessions/launchpad#show"
   end
 
+  namespace :signup do
+    get "/" => "accounts#new"
+    resources :accounts, only: %i[ new create ]
+  end
+
   resources :users do
     scope module: :users do
       resource :avatar
diff --git a/test/controllers/signup/accounts_controller_test.rb b/test/controllers/signup/accounts_controller_test.rb
new file mode 100644
index 000000000..f7c2a6ad7
--- /dev/null
+++ b/test/controllers/signup/accounts_controller_test.rb
@@ -0,0 +1,39 @@
+require "test_helper"
+
+class Signup::AccountsControllerTest < ActionDispatch::IntegrationTest
+  test "new at a tenanted domain" do
+    get new_signup_account_url
+
+    assert_redirected_to root_url
+  end
+
+  test "new at an untenanted domain" do
+    integration_session.host = "example.com" # no subdomain
+
+    get new_signup_account_url
+
+    assert_response :success
+  end
+
+  test "create with invalid params" do
+    integration_session.host = "example.com" # no subdomain
+
+    post signup_accounts_url, params: { signup: { full_name: "Jim", email_address: "jim@example.com", password: "", company_name: "" } }
+
+    assert_response :unprocessable_entity
+    assert_select "div.alert--error", text: /you need to choose a password/i
+  end
+
+  test "create for a new " do
+    integration_session.host = "example.com" # no subdomain
+
+    assert_difference -> { SignalId::Identity.count }, +1 do
+      assert_difference -> { SignalId::Account.count }, +1 do
+        post signup_accounts_url, params: { signup: { full_name: "Jim", email_address: "jim@example.com", password: SecureRandom.hex(12), company_name: "signup-accounts-controller-test-1" } }
+      end
+    end
+
+    signal_account = SignalId::Account.last
+    assert_redirected_to(/#{signal_account.login_url}/)
+  end
+end