diff --git a/docs/architecture.md b/docs/architecture.md
index 14a916d..b899d4b 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -211,6 +211,15 @@ one `INSERT ... ON CONFLICT` statement. Failed transactional-email delivery
 removes only the token created for that failed attempt. Expired buckets and
 tokens are pruned by the maintenance worker.
 
+Authentication delivery also reuses the validity window of an existing
+one-time link as an idempotency window: a repeated request for the same account
+and flow does not create or send another link while the previous one remains
+valid. The account row is locked only while reserving the token, so concurrent
+requests cannot produce duplicate messages and SMTP work does not run inside a
+database transaction. Google verification flows include a non-reversible hash
+of the pending flow in the token context, so a new OAuth flow is not suppressed
+by an older one.
+
 The Compose and kind scripts finish by subscribing on one live BEAM node,
 broadcasting through a different connected node, and failing if the PubSub
 probe is not received.
diff --git a/lib/who_need_help/accounts.ex b/lib/who_need_help/accounts.ex
index d9a71fb..4abd7fb 100644
--- a/lib/who_need_help/accounts.ex
+++ b/lib/who_need_help/accounts.ex
@@ -1067,9 +1067,10 @@ defmodule WhoNeedHelp.Accounts do
   end
 
   @doc "Delivers a one-time local-account verification link before connecting Google."
-  def deliver_google_link_instructions(%User{} = user, magic_link_url_fun)
-      when is_function(magic_link_url_fun, 1) do
-    {encoded_token, user_token} = UserToken.build_email_token(user, "login")
+  def deliver_google_link_instructions(%User{} = user, delivery_key, magic_link_url_fun)
+      when is_binary(delivery_key) and is_function(magic_link_url_fun, 1) do
+    context = "login:google:#{short_hash(delivery_key)}"
+    {encoded_token, user_token} = UserToken.build_email_token(user, context)
 
     persist_email_token_and_deliver(user_token, fn ->
       UserNotifier.deliver_google_link_instructions(user, magic_link_url_fun.(encoded_token))
@@ -1093,8 +1094,54 @@ defmodule WhoNeedHelp.Accounts do
   ## Token helper
 
   defp persist_email_token_and_deliver(user_token, deliver_fun) do
-    persisted_token = Repo.insert!(user_token)
+    case reserve_email_token(user_token) do
+      {:ok, :already_sent} ->
+        {:ok, :already_sent}
 
+      {:ok, persisted_token} ->
+        deliver_reserved_email_token(persisted_token, deliver_fun)
+
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
+  defp reserve_email_token(%UserToken{context: "login"} = user_token),
+    do: reserve_auth_email_token(user_token)
+
+  defp reserve_email_token(%UserToken{context: "login:google:" <> _} = user_token),
+    do: reserve_auth_email_token(user_token)
+
+  defp reserve_email_token(user_token), do: {:ok, Repo.insert!(user_token)}
+
+  defp reserve_auth_email_token(user_token) do
+    cutoff =
+      DateTime.utc_now(:second)
+      |> DateTime.add(-UserToken.magic_link_validity_in_minutes(), :minute)
+
+    Repo.transact(fn ->
+      # Serialize reservations per account so concurrent requests cannot both send.
+      Repo.one!(
+        from user in User,
+          where: user.id == ^user_token.user_id,
+          select: user.id,
+          lock: "FOR UPDATE"
+      )
+
+      recent_token? =
+        Repo.exists?(
+          from token in UserToken,
+            where: token.user_id == ^user_token.user_id,
+            where: token.context == ^user_token.context,
+            where: token.sent_to == ^user_token.sent_to,
+            where: token.inserted_at > ^cutoff
+        )
+
+      if recent_token?, do: {:ok, :already_sent}, else: Repo.insert(user_token)
+    end)
+  end
+
+  defp deliver_reserved_email_token(persisted_token, deliver_fun) do
     case deliver_fun.() do
       {:ok, _email} = delivered ->
         delivered
@@ -1105,6 +1152,12 @@ defmodule WhoNeedHelp.Accounts do
     end
   end
 
+  defp short_hash(value) do
+    :crypto.hash(:sha256, value)
+    |> Base.url_encode64(padding: false)
+    |> binary_part(0, 22)
+  end
+
   defp before_moderation_user(query, nil), do: query
 
   defp before_moderation_user(query, {inserted_at, id}) do
diff --git a/lib/who_need_help/accounts/user_notifier.ex b/lib/who_need_help/accounts/user_notifier.ex
index d8b6592..98f363f 100644
--- a/lib/who_need_help/accounts/user_notifier.ex
+++ b/lib/who_need_help/accounts/user_notifier.ex
@@ -7,7 +7,7 @@ defmodule WhoNeedHelp.Accounts.UserNotifier do
   alias WhoNeedHelp.Accounts.User
 
   # Delivers the email using the application mailer.
-  defp deliver(recipient, subject, body) do
+  defp deliver(recipient, subject, text_body, html_body) do
     from = Application.fetch_env!(:who_need_help, :mailer_from)
 
     email =
@@ -15,7 +15,8 @@ defmodule WhoNeedHelp.Accounts.UserNotifier do
       |> to(recipient)
       |> from({from[:name], from[:address]})
       |> subject(subject)
-      |> text_body(body)
+      |> text_body(text_body)
+      |> html_body(html_body)
 
     with {:ok, _metadata} <- Mailer.deliver(email) do
       {:ok, email}
@@ -27,14 +28,18 @@ defmodule WhoNeedHelp.Accounts.UserNotifier do
   """
   def deliver_update_email_instructions(user, url) do
     with_user_locale(user, fn ->
-      deliver(
-        user.email,
-        gettext("Update email instructions"),
-        gettext(
-          "Hi %{email},\n\nYou can change your email by visiting the URL below:\n\n%{url}\n\nIf you didn't request this change, please ignore this.",
-          email: user.email,
-          url: url
-        )
+      deliver_action_email(user,
+        subject: gettext("Confirm your Who Need Help email change"),
+        heading: gettext("Confirm your new email address"),
+        introduction:
+          gettext("Use the secure link below to confirm this email address for your account."),
+        action_label: gettext("Confirm email address"),
+        url: url,
+        expiry_note: gettext("This confirmation link expires in 7 days."),
+        security_note:
+          gettext(
+            "If you did not request this change, ignore this email. Your address will not change."
+          )
       )
     end)
   end
@@ -52,46 +57,143 @@ defmodule WhoNeedHelp.Accounts.UserNotifier do
   @doc "Delivers instructions for verifying a local account before connecting Google sign-in."
   def deliver_google_link_instructions(user, url) do
     with_user_locale(user, fn ->
-      deliver(
-        user.email,
-        gettext("Confirm Google sign-in"),
-        gettext(
-          "Hi %{email},\n\nUse the secure link below to sign in and connect Google to your Who Need Help account:\n\n%{url}\n\nIf you did not request this, ignore this email. Google will not be connected.",
-          email: user.email,
-          url: url
-        )
+      deliver_action_email(user,
+        subject: gettext("Confirm Google sign-in for Who Need Help"),
+        heading: gettext("Confirm Google sign-in"),
+        introduction:
+          gettext("Use the secure link below to sign in and connect Google to your account."),
+        action_label: gettext("Confirm Google sign-in"),
+        url: url,
+        expiry_note: gettext("This one-time link expires in 15 minutes."),
+        security_note:
+          gettext("If you did not request this, ignore this email. Google will not be connected.")
       )
     end)
   end
 
   defp deliver_magic_link_instructions(user, url) do
     with_user_locale(user, fn ->
-      deliver(
-        user.email,
-        gettext("Log in instructions"),
-        gettext(
-          "Hi %{email},\n\nYou can log into your account by visiting the URL below:\n\n%{url}\n\nIf you didn't request this email, please ignore this.",
-          email: user.email,
-          url: url
-        )
+      deliver_action_email(user,
+        subject: gettext("Your Who Need Help sign-in link"),
+        heading: gettext("Sign in to Who Need Help"),
+        introduction: gettext("Use the secure link below to sign in to your account."),
+        action_label: gettext("Sign in to Who Need Help"),
+        url: url,
+        expiry_note: gettext("This one-time link expires in 15 minutes."),
+        security_note:
+          gettext("If you did not request this sign-in, you can safely ignore this email.")
       )
     end)
   end
 
   defp deliver_confirmation_instructions(user, url) do
     with_user_locale(user, fn ->
-      deliver(
-        user.email,
-        gettext("Confirmation instructions"),
-        gettext(
-          "Hi %{email},\n\nYou can confirm your account by visiting the URL below:\n\n%{url}\n\nIf you didn't create an account with us, please ignore this.",
-          email: user.email,
-          url: url
-        )
+      deliver_action_email(user,
+        subject: gettext("Confirm your Who Need Help account"),
+        heading: gettext("Confirm your account"),
+        introduction: gettext("Use the secure link below to confirm your Who Need Help account."),
+        action_label: gettext("Confirm account"),
+        url: url,
+        expiry_note: gettext("This one-time link expires in 15 minutes."),
+        security_note:
+          gettext("If you did not create this account, you can safely ignore this email.")
       )
     end)
   end
 
+  defp deliver_action_email(user, content) do
+    subject = Keyword.fetch!(content, :subject)
+    heading = Keyword.fetch!(content, :heading)
+    introduction = Keyword.fetch!(content, :introduction)
+    action_label = Keyword.fetch!(content, :action_label)
+    url = Keyword.fetch!(content, :url)
+    expiry_note = Keyword.fetch!(content, :expiry_note)
+    security_note = Keyword.fetch!(content, :security_note)
+
+    text = """
+    #{heading}
+
+    #{introduction}
+
+    #{action_label}: #{url}
+
+    #{expiry_note}
+
+    #{security_note}
+
+    Who Need Help
+    """
+
+    html = action_email_html(heading, introduction, action_label, url, expiry_note, security_note)
+
+    deliver(user.email, subject, text, html)
+  end
+
+  defp action_email_html(heading, introduction, action_label, url, expiry_note, security_note) do
+    escaped_heading = escape_html(heading)
+    escaped_introduction = escape_html(introduction)
+    escaped_action_label = escape_html(action_label)
+    escaped_url = escape_html(url)
+    escaped_expiry_note = escape_html(expiry_note)
+    escaped_security_note = escape_html(security_note)
+
+    """
+    <!doctype html>
+    <html lang="#{escape_html(Gettext.get_locale(WhoNeedHelpWeb.Gettext))}">
+      <head>
+        <meta charset="utf-8">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <meta name="color-scheme" content="light">
+        <title>#{escaped_heading}</title>
+      </head>
+      <body style="margin:0;padding:0;background:#f5f7f6;color:#1d1d20;font-family:Arial,Helvetica,sans-serif;">
+        <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0" style="background:#f5f7f6;">
+          <tr>
+            <td align="center" style="padding:32px 16px;">
+              <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0" style="max-width:560px;background:#ffffff;border:1px solid #dfe5e2;border-radius:16px;">
+                <tr>
+                  <td style="padding:28px 32px 12px;font-size:18px;font-weight:700;color:#007d6b;">Who Need Help</td>
+                </tr>
+                <tr>
+                  <td style="padding:8px 32px 0;">
+                    <h1 style="margin:0;font-size:26px;line-height:1.25;color:#1d1d20;">#{escaped_heading}</h1>
+                  </td>
+                </tr>
+                <tr>
+                  <td style="padding:16px 32px 0;font-size:16px;line-height:1.6;color:#555b58;">#{escaped_introduction}</td>
+                </tr>
+                <tr>
+                  <td style="padding:24px 32px;">
+                    <a href="#{escaped_url}" style="display:inline-block;padding:13px 20px;border-radius:8px;background:#a93612;color:#ffffff;text-decoration:none;font-size:16px;font-weight:700;">#{escaped_action_label}</a>
+                  </td>
+                </tr>
+                <tr>
+                  <td style="padding:0 32px 8px;font-size:14px;line-height:1.55;color:#555b58;">#{escaped_expiry_note}</td>
+                </tr>
+                <tr>
+                  <td style="padding:8px 32px 0;font-size:14px;line-height:1.55;color:#555b58;">#{escaped_security_note}</td>
+                </tr>
+                <tr>
+                  <td style="padding:20px 32px 8px;font-size:12px;line-height:1.5;color:#747a77;">#{escape_html(gettext("If the button does not work, copy and paste this address into your browser:"))}</td>
+                </tr>
+                <tr>
+                  <td style="padding:0 32px 28px;font-size:12px;line-height:1.5;word-break:break-all;"><a href="#{escaped_url}" style="color:#007d6b;">#{escaped_url}</a></td>
+                </tr>
+              </table>
+            </td>
+          </tr>
+        </table>
+      </body>
+    </html>
+    """
+  end
+
+  defp escape_html(value) do
+    value
+    |> Phoenix.HTML.html_escape()
+    |> Phoenix.HTML.safe_to_string()
+  end
+
   defp with_user_locale(%User{locale: locale}, fun) do
     Gettext.with_locale(WhoNeedHelpWeb.Gettext, WhoNeedHelp.Locales.normalize(locale), fun)
   end
diff --git a/lib/who_need_help/accounts/user_token.ex b/lib/who_need_help/accounts/user_token.ex
index 11845d2..a52a1cd 100644
--- a/lib/who_need_help/accounts/user_token.ex
+++ b/lib/who_need_help/accounts/user_token.ex
@@ -12,6 +12,8 @@ defmodule WhoNeedHelp.Accounts.UserToken do
   @change_email_validity_in_days 7
   @session_validity_in_days 14
 
+  def magic_link_validity_in_minutes, do: @magic_link_validity_in_minutes
+
   @primary_key {:id, :binary_id, autogenerate: true}
   @foreign_key_type :binary_id
   schema "users_tokens" do
@@ -113,7 +115,9 @@ defmodule WhoNeedHelp.Accounts.UserToken do
         hashed_token = :crypto.hash(@hash_algorithm, decoded_token)
 
         query =
-          from token in by_token_and_context_query(hashed_token, "login"),
+          from token in UserToken,
+            where: token.token == ^hashed_token,
+            where: token.context == "login" or like(token.context, "login:google:%"),
             join: user in assoc(token, :user),
             where: token.inserted_at > ago(^@magic_link_validity_in_minutes, "minute"),
             where: token.sent_to == user.email,
@@ -160,7 +164,7 @@ defmodule WhoNeedHelp.Accounts.UserToken do
 
     from token in UserToken,
       where:
-        (token.context == "login" and token.inserted_at <= ^magic_link_cutoff) or
+        (like(token.context, "login%") and token.inserted_at <= ^magic_link_cutoff) or
           (like(token.context, "change:%") and token.inserted_at <= ^change_email_cutoff) or
           (token.context == "session" and token.inserted_at <= ^session_cutoff)
   end
diff --git a/lib/who_need_help_web/controllers/google_auth_controller.ex b/lib/who_need_help_web/controllers/google_auth_controller.ex
index a37ccac..8cdf1ae 100644
--- a/lib/who_need_help_web/controllers/google_auth_controller.ex
+++ b/lib/who_need_help_web/controllers/google_auth_controller.ex
@@ -525,6 +525,7 @@ defmodule WhoNeedHelpWeb.GoogleAuthController do
 
     Accounts.deliver_google_link_instructions(
       user,
+      pending_token,
       &"#{login_url}?google_link=#{URI.encode_www_form(pending_token)}#token=#{URI.encode_www_form(&1)}"
     )
   end
diff --git a/lib/who_need_help_web/controllers/user_registration_html/sent.html.heex b/lib/who_need_help_web/controllers/user_registration_html/sent.html.heex
index 396286b..f7f074a 100644
--- a/lib/who_need_help_web/controllers/user_registration_html/sent.html.heex
+++ b/lib/who_need_help_web/controllers/user_registration_html/sent.html.heex
@@ -12,7 +12,7 @@
           else: gettext("Sign-in request processed")}
         <:subtitle>
           <%= if @email_flow == "register" do %>
-            {gettext("Use the newest confirmation link if it arrives.")}
+            {gettext("Use the most recent confirmation link that arrived.")}
           <% else %>
             {gettext("Signing in does not create a new account.")}
           <% end %>
@@ -48,7 +48,7 @@
         <div>
           <h2 class="text-lg font-bold">
             <%= if @email_flow == "register" do %>
-              {gettext("Open the newest Who Need Help email")}
+              {gettext("Open the most recent Who Need Help email")}
             <% else %>
               {gettext("Already registered? Check your email")}
             <% end %>
@@ -69,7 +69,7 @@
 
       <div class="mt-6 rounded-2xl bg-base-200 p-4 text-sm leading-6 text-base-content/70">
         {gettext(
-          "If the message is not in your inbox after a minute, check Spam. Older secure links may have been replaced by the newest one."
+          "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
         )}
       </div>
 
diff --git a/priv/gettext/default.pot b/priv/gettext/default.pot
index 50a89a8..96cc31c 100644
--- a/priv/gettext/default.pot
+++ b/priv/gettext/default.pot
@@ -4087,7 +4087,7 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:71
 #, elixir-autogen, elixir-format
-msgid "If the message is not in your inbox after a minute, check Spam. Older secure links may have been replaced by the newest one."
+msgid "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
 msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:36
@@ -4166,7 +4166,7 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:51
 #, elixir-autogen, elixir-format
-msgid "Open the newest Who Need Help email"
+msgid "Open the most recent Who Need Help email"
 msgstr ""
 
 #: lib/who_need_help_web/live/public_profile_live.ex:105
@@ -4380,7 +4380,7 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:15
 #, elixir-autogen, elixir-format
-msgid "Use the newest confirmation link if it arrives."
+msgid "Use the most recent confirmation link that arrived."
 msgstr ""
 
 #: lib/who_need_help_web/live/request_live/show.ex:1658
@@ -6828,3 +6828,83 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "We saved pending request %{reference}. It is not in the support queue yet. Open the private link sent to the contact email to verify the address and submit the request for review."
 msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help email change"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your new email address"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm this email address for your account."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm email address"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This confirmation link expires in 7 days."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this change, ignore this email. Your address will not change."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm Google sign-in for Who Need Help"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in and connect Google to your account."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This one-time link expires in 15 minutes."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this, ignore this email. Google will not be connected."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Your Who Need Help sign-in link"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Sign in to Who Need Help"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in to your account."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this sign-in, you can safely ignore this email."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help account"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your account"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm your Who Need Help account."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm account"
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not create this account, you can safely ignore this email."
+msgstr ""
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If the button does not work, copy and paste this address into your browser:"
+msgstr ""
diff --git a/priv/gettext/en/LC_MESSAGES/default.po b/priv/gettext/en/LC_MESSAGES/default.po
index 772d3cc..d6ac092 100644
--- a/priv/gettext/en/LC_MESSAGES/default.po
+++ b/priv/gettext/en/LC_MESSAGES/default.po
@@ -4087,8 +4087,8 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:71
 #, elixir-autogen, elixir-format
-msgid "If the message is not in your inbox after a minute, check Spam. Older secure links may have been replaced by the newest one."
-msgstr ""
+msgid "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
+msgstr "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:36
 #, elixir-autogen, elixir-format
@@ -4166,8 +4166,8 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:51
 #, elixir-autogen, elixir-format
-msgid "Open the newest Who Need Help email"
-msgstr ""
+msgid "Open the most recent Who Need Help email"
+msgstr "Open the most recent Who Need Help email"
 
 #: lib/who_need_help_web/live/public_profile_live.ex:105
 #, elixir-autogen, elixir-format, fuzzy
@@ -4380,8 +4380,8 @@ msgstr ""
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:15
 #, elixir-autogen, elixir-format
-msgid "Use the newest confirmation link if it arrives."
-msgstr ""
+msgid "Use the most recent confirmation link that arrived."
+msgstr "Use the most recent confirmation link that arrived."
 
 #: lib/who_need_help_web/live/request_live/show.ex:1658
 #, elixir-autogen, elixir-format
@@ -6828,3 +6828,83 @@ msgstr "Pending email verification"
 #, elixir-autogen, elixir-format
 msgid "We saved pending request %{reference}. It is not in the support queue yet. Open the private link sent to the contact email to verify the address and submit the request for review."
 msgstr "We saved pending request %{reference}. It is not in the support queue yet. Open the private link sent to the contact email to verify the address and submit the request for review."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help email change"
+msgstr "Confirm your Who Need Help email change"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your new email address"
+msgstr "Confirm your new email address"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm this email address for your account."
+msgstr "Use the secure link below to confirm this email address for your account."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm email address"
+msgstr "Confirm email address"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This confirmation link expires in 7 days."
+msgstr "This confirmation link expires in 7 days."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this change, ignore this email. Your address will not change."
+msgstr "If you did not request this change, ignore this email. Your address will not change."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm Google sign-in for Who Need Help"
+msgstr "Confirm Google sign-in for Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in and connect Google to your account."
+msgstr "Use the secure link below to sign in and connect Google to your account."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This one-time link expires in 15 minutes."
+msgstr "This one-time link expires in 15 minutes."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this, ignore this email. Google will not be connected."
+msgstr "If you did not request this, ignore this email. Google will not be connected."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Your Who Need Help sign-in link"
+msgstr "Your Who Need Help sign-in link"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Sign in to Who Need Help"
+msgstr "Sign in to Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in to your account."
+msgstr "Use the secure link below to sign in to your account."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this sign-in, you can safely ignore this email."
+msgstr "If you did not request this sign-in, you can safely ignore this email."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help account"
+msgstr "Confirm your Who Need Help account"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your account"
+msgstr "Confirm your account"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm your Who Need Help account."
+msgstr "Use the secure link below to confirm your Who Need Help account."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm account"
+msgstr "Confirm account"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not create this account, you can safely ignore this email."
+msgstr "If you did not create this account, you can safely ignore this email."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If the button does not work, copy and paste this address into your browser:"
+msgstr "If the button does not work, copy and paste this address into your browser:"
diff --git a/priv/gettext/ru/LC_MESSAGES/default.po b/priv/gettext/ru/LC_MESSAGES/default.po
index 431aadd..2d6dd97 100644
--- a/priv/gettext/ru/LC_MESSAGES/default.po
+++ b/priv/gettext/ru/LC_MESSAGES/default.po
@@ -4227,8 +4227,8 @@ msgstr "Помощники увидят только указанный выше
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:71
 #, elixir-autogen, elixir-format
-msgid "If the message is not in your inbox after a minute, check Spam. Older secure links may have been replaced by the newest one."
-msgstr "Если письмо не появилось через минуту, проверьте папку «Спам». Новая защищённая ссылка могла заменить предыдущие."
+msgid "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
+msgstr "Если письмо не появилось через минуту, проверьте папку «Спам». Повторный запрос не отправляет ещё одно письмо, пока недавняя защищённая ссылка остаётся действительной."
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:36
 #, elixir-autogen, elixir-format
@@ -4306,8 +4306,8 @@ msgstr "Открыть ссылку для благодарности"
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:51
 #, elixir-autogen, elixir-format
-msgid "Open the newest Who Need Help email"
-msgstr "Откройте последнее письмо Who Need Help"
+msgid "Open the most recent Who Need Help email"
+msgstr "Откройте последнее полученное письмо Who Need Help"
 
 #: lib/who_need_help_web/live/public_profile_live.ex:105
 #, elixir-autogen, elixir-format
@@ -4520,8 +4520,8 @@ msgstr "Перейдите по ссылке подтверждения в пи
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:15
 #, elixir-autogen, elixir-format
-msgid "Use the newest confirmation link if it arrives."
-msgstr "Если пришла новая ссылка подтверждения, используйте её."
+msgid "Use the most recent confirmation link that arrived."
+msgstr "Используйте последнюю полученную ссылку подтверждения."
 
 #: lib/who_need_help_web/live/request_live/show.ex:1658
 #, elixir-autogen, elixir-format
@@ -6971,3 +6971,83 @@ msgstr "Ожидает подтверждения email"
 #, elixir-autogen, elixir-format
 msgid "We saved pending request %{reference}. It is not in the support queue yet. Open the private link sent to the contact email to verify the address and submit the request for review."
 msgstr "Мы сохранили ожидающую заявку %{reference}. Она ещё не попала в очередь поддержки. Откройте приватную ссылку из письма, чтобы подтвердить адрес и отправить заявку на рассмотрение."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help email change"
+msgstr "Подтвердите изменение email в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your new email address"
+msgstr "Подтвердите новый адрес электронной почты"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm this email address for your account."
+msgstr "Перейдите по защищённой ссылке ниже, чтобы подтвердить этот адрес электронной почты для своей учётной записи."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm email address"
+msgstr "Подтвердить email"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This confirmation link expires in 7 days."
+msgstr "Ссылка для подтверждения действует 7 дней."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this change, ignore this email. Your address will not change."
+msgstr "Если вы не запрашивали это изменение, проигнорируйте письмо. Ваш адрес не изменится."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm Google sign-in for Who Need Help"
+msgstr "Подтвердите вход через Google в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in and connect Google to your account."
+msgstr "Перейдите по защищённой ссылке ниже, чтобы войти и подключить Google к своей учётной записи."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This one-time link expires in 15 minutes."
+msgstr "Эта одноразовая ссылка действует 15 минут."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this, ignore this email. Google will not be connected."
+msgstr "Если вы этого не запрашивали, проигнорируйте письмо. Google не будет подключён."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Your Who Need Help sign-in link"
+msgstr "Ваша ссылка для входа в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Sign in to Who Need Help"
+msgstr "Войти в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in to your account."
+msgstr "Перейдите по защищённой ссылке ниже, чтобы войти в свою учётную запись."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this sign-in, you can safely ignore this email."
+msgstr "Если вы не запрашивали вход, просто проигнорируйте это письмо."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help account"
+msgstr "Подтвердите учётную запись Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your account"
+msgstr "Подтвердите учётную запись"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm your Who Need Help account."
+msgstr "Перейдите по защищённой ссылке ниже, чтобы подтвердить учётную запись Who Need Help."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm account"
+msgstr "Подтвердить учётную запись"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not create this account, you can safely ignore this email."
+msgstr "Если вы не создавали эту учётную запись, просто проигнорируйте письмо."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If the button does not work, copy and paste this address into your browser:"
+msgstr "Если кнопка не работает, скопируйте этот адрес и вставьте его в браузер:"
diff --git a/priv/gettext/uk/LC_MESSAGES/default.po b/priv/gettext/uk/LC_MESSAGES/default.po
index 2341a4c..0100343 100644
--- a/priv/gettext/uk/LC_MESSAGES/default.po
+++ b/priv/gettext/uk/LC_MESSAGES/default.po
@@ -4221,8 +4221,8 @@ msgstr "Помічники бачитимуть лише вказаний вищ
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:71
 #, elixir-autogen, elixir-format
-msgid "If the message is not in your inbox after a minute, check Spam. Older secure links may have been replaced by the newest one."
-msgstr "Якщо лист не з’явився за хвилину, перевірте папку «Спам». Нове захищене посилання могло замінити попередні."
+msgid "If the message is not in your inbox after a minute, check Spam. Repeated requests do not send another email while a recent secure link is still valid."
+msgstr "Якщо лист не з’явився за хвилину, перевірте папку «Спам». Повторний запит не надсилає ще одного листа, доки нещодавнє захищене посилання залишається чинним."
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:36
 #, elixir-autogen, elixir-format
@@ -4300,8 +4300,8 @@ msgstr "Відкрити посилання для подяки"
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:51
 #, elixir-autogen, elixir-format
-msgid "Open the newest Who Need Help email"
-msgstr "Відкрийте останній лист Who Need Help"
+msgid "Open the most recent Who Need Help email"
+msgstr "Відкрийте останній отриманий лист Who Need Help"
 
 #: lib/who_need_help_web/live/public_profile_live.ex:105
 #, elixir-autogen, elixir-format
@@ -4514,8 +4514,8 @@ msgstr "Перейдіть за посиланням підтвердження
 
 #: lib/who_need_help_web/controllers/user_registration_html/sent.html.heex:15
 #, elixir-autogen, elixir-format
-msgid "Use the newest confirmation link if it arrives."
-msgstr "Якщо надійшло нове посилання підтвердження, використайте його."
+msgid "Use the most recent confirmation link that arrived."
+msgstr "Скористайтеся останнім отриманим посиланням підтвердження."
 
 #: lib/who_need_help_web/live/request_live/show.ex:1658
 #, elixir-autogen, elixir-format
@@ -6965,3 +6965,83 @@ msgstr "Очікує підтвердження email"
 #, elixir-autogen, elixir-format
 msgid "We saved pending request %{reference}. It is not in the support queue yet. Open the private link sent to the contact email to verify the address and submit the request for review."
 msgstr "Ми зберегли запит %{reference}, що очікує підтвердження. Він ще не потрапив до черги підтримки. Відкрийте приватне посилання з листа, щоб підтвердити адресу та надіслати запит на розгляд."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help email change"
+msgstr "Підтвердьте зміну email у Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your new email address"
+msgstr "Підтвердьте нову адресу електронної пошти"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm this email address for your account."
+msgstr "Перейдіть за захищеним посиланням нижче, щоб підтвердити цю адресу електронної пошти для свого облікового запису."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm email address"
+msgstr "Підтвердити email"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This confirmation link expires in 7 days."
+msgstr "Посилання для підтвердження діє 7 днів."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this change, ignore this email. Your address will not change."
+msgstr "Якщо ви не запитували цю зміну, проігноруйте лист. Ваша адреса не зміниться."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm Google sign-in for Who Need Help"
+msgstr "Підтвердьте вхід через Google у Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in and connect Google to your account."
+msgstr "Перейдіть за захищеним посиланням нижче, щоб увійти й підключити Google до свого облікового запису."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "This one-time link expires in 15 minutes."
+msgstr "Це одноразове посилання діє 15 хвилин."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this, ignore this email. Google will not be connected."
+msgstr "Якщо ви цього не запитували, проігноруйте лист. Google не буде підключено."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Your Who Need Help sign-in link"
+msgstr "Ваше посилання для входу в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Sign in to Who Need Help"
+msgstr "Увійти в Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to sign in to your account."
+msgstr "Перейдіть за захищеним посиланням нижче, щоб увійти до свого облікового запису."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not request this sign-in, you can safely ignore this email."
+msgstr "Якщо ви не запитували вхід, просто проігноруйте цей лист."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your Who Need Help account"
+msgstr "Підтвердьте обліковий запис Who Need Help"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm your account"
+msgstr "Підтвердьте обліковий запис"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Use the secure link below to confirm your Who Need Help account."
+msgstr "Перейдіть за захищеним посиланням нижче, щоб підтвердити обліковий запис Who Need Help."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "Confirm account"
+msgstr "Підтвердити обліковий запис"
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If you did not create this account, you can safely ignore this email."
+msgstr "Якщо ви не створювали цей обліковий запис, просто проігноруйте лист."
+
+#: lib/who_need_help/accounts/user_notifier.ex
+msgid "If the button does not work, copy and paste this address into your browser:"
+msgstr "Якщо кнопка не працює, скопіюйте цю адресу та вставте її у браузер:"
diff --git a/test/who_need_help/accounts/user_notifier_test.exs b/test/who_need_help/accounts/user_notifier_test.exs
new file mode 100644
index 0000000..84248fb
--- /dev/null
+++ b/test/who_need_help/accounts/user_notifier_test.exs
@@ -0,0 +1,72 @@
+defmodule WhoNeedHelp.Accounts.UserNotifierTest do
+  use ExUnit.Case, async: true
+
+  alias WhoNeedHelp.Accounts.{User, UserNotifier}
+
+  test "magic-link email is recognizable, multipart, and explicit about expiry" do
+    user = %User{
+      email: "person@example.com",
+      display_name: "Helpful neighbor",
+      locale: "en",
+      confirmed_at: DateTime.utc_now(:second)
+    }
+
+    url = "https://whoneedhelp.com/users/log-in#token=one-time-token"
+
+    assert {:ok, email} = UserNotifier.deliver_login_instructions(user, url)
+
+    assert email.subject == "Your Who Need Help sign-in link"
+    assert email.text_body =~ "This one-time link expires in 15 minutes."
+    assert email.text_body =~ url
+    refute email.text_body =~ user.email
+
+    assert email.html_body =~ "<title>Sign in to Who Need Help</title>"
+    assert email.html_body =~ ~s(href="#{url}")
+    assert email.html_body =~ "copy and paste this address into your browser"
+    refute email.html_body =~ "<img"
+    refute email.html_body =~ user.email
+  end
+
+  test "account email HTML escapes translated content and action URLs" do
+    user = %User{email: "person@example.com", locale: "en"}
+    url = ~s(https://whoneedhelp.com/users/log-in#token=a&next="unsafe")
+
+    assert {:ok, email} = UserNotifier.deliver_login_instructions(user, url)
+
+    assert email.text_body =~ url
+    assert email.html_body =~ "a&amp;next=&quot;unsafe&quot;"
+    refute email.html_body =~ ~s(href="#{url}")
+  end
+
+  test "new-account confirmation uses an account-specific subject" do
+    user = %User{email: "person@example.com", locale: "en", confirmed_at: nil}
+
+    assert {:ok, email} =
+             UserNotifier.deliver_login_instructions(
+               user,
+               "https://whoneedhelp.com/users/log-in#token=confirmation-token"
+             )
+
+    assert email.subject == "Confirm your Who Need Help account"
+    assert email.text_body =~ "Confirm your account"
+    assert email.html_body =~ "Confirm account"
+  end
+
+  test "Google-link verification has a distinct recognizable subject" do
+    user = %User{
+      email: "person@example.com",
+      locale: "en",
+      confirmed_at: DateTime.utc_now(:second)
+    }
+
+    assert {:ok, email} =
+             UserNotifier.deliver_google_link_instructions(
+               user,
+               "https://whoneedhelp.com/users/log-in?google_link=pending#token=one-time-token"
+             )
+
+    assert email.subject == "Confirm Google sign-in for Who Need Help"
+    assert email.text_body =~ "Google will not be connected"
+    assert email.html_body =~ "Confirm Google sign-in"
+  end
+end
diff --git a/test/who_need_help/accounts_test.exs b/test/who_need_help/accounts_test.exs
index 7d0c41b..ef8f825 100644
--- a/test/who_need_help/accounts_test.exs
+++ b/test/who_need_help/accounts_test.exs
@@ -703,6 +703,72 @@ defmodule WhoNeedHelp.AccountsTest do
                  where: token.user_id == ^user.id and token.context == "login"
              )
     end
+
+    test "does not send another login email while the previous link is valid", %{user: user} do
+      assert {:ok, first_email} =
+               Accounts.deliver_login_instructions(user, &"https://example.test/#{&1}")
+
+      assert {:ok, :already_sent} =
+               Accounts.deliver_login_instructions(user, &"https://example.test/#{&1}")
+
+      assert first_email.subject == "Confirm your Who Need Help account"
+
+      assert Repo.aggregate(
+               from(token in UserToken,
+                 where: token.user_id == ^user.id and token.context == "login"
+               ),
+               :count
+             ) == 1
+    end
+
+    test "allows a new login email after the existing link expires", %{user: user} do
+      assert {:ok, _email} =
+               Accounts.deliver_login_instructions(user, &"https://example.test/#{&1}")
+
+      Repo.update_all(
+        from(token in UserToken,
+          where: token.user_id == ^user.id and token.context == "login"
+        ),
+        set: [inserted_at: DateTime.add(DateTime.utc_now(:second), -16, :minute)]
+      )
+
+      assert {:ok, _email} =
+               Accounts.deliver_login_instructions(user, &"https://example.test/#{&1}")
+
+      assert Repo.aggregate(
+               from(token in UserToken,
+                 where: token.user_id == ^user.id and token.context == "login"
+               ),
+               :count
+             ) == 2
+    end
+
+    test "deduplicates only the same pending Google verification flow", %{user: user} do
+      url = &"https://example.test/google/[TOKEN]#{&1}[TOKEN]"
+
+      assert {:ok, first_email} =
+               Accounts.deliver_google_link_instructions(user, "pending-flow-one", url)
+
+      [_, token | _] = String.split(first_email.text_body, "[TOKEN]")
+      assert %User{id: user_id} = Accounts.get_user_by_magic_link_token(token)
+      assert user_id == user.id
+
+      assert {:ok, :already_sent} =
+               Accounts.deliver_google_link_instructions(user, "pending-flow-one", url)
+
+      assert {:ok, _email} =
+               Accounts.deliver_google_link_instructions(user, "pending-flow-two", url)
+
+      contexts =
+        UserToken
+        |> where([token], token.user_id == ^user.id)
+        |> select([token], token.context)
+        |> Repo.all()
+
+      assert length(contexts) == 2
+      assert Enum.all?(contexts, &String.starts_with?(&1, "login:google:"))
+      assert contexts |> MapSet.new() |> MapSet.size() == 2
+    end
   end
 
   describe "inspect/2 for the User module" do
diff --git a/test/who_need_help_web/controllers/google_auth_controller_test.exs b/test/who_need_help_web/controllers/google_auth_controller_test.exs
index 0175927..01e0e88 100644
--- a/test/who_need_help_web/controllers/google_auth_controller_test.exs
+++ b/test/who_need_help_web/controllers/google_auth_controller_test.exs
@@ -506,8 +506,8 @@ defmodule WhoNeedHelpWeb.GoogleAuthControllerTest do
     assert Phoenix.Flash.get(conn.assigns.flash, :info) =~ "finish connecting Google"
 
     assert_email_sent(fn email ->
-      email.subject == "Confirm Google sign-in" and
-        email.text_body =~ "connect Google to your Who Need Help account" and
+      email.subject == "Confirm Google sign-in for Who Need Help" and
+        email.text_body =~ "connect Google to your account" and
         email.text_body =~ "google_link=" and email.text_body =~ "#token="
     end)