diff --git a/lib/plausible/billing/enterprise_plan.ex b/lib/plausible/billing/enterprise_plan.ex
index afc166cc8805..36ccd0a1d6a9 100644
--- a/lib/plausible/billing/enterprise_plan.ex
+++ b/lib/plausible/billing/enterprise_plan.ex
@@ -36,6 +36,5 @@ defmodule Plausible.Billing.EnterprisePlan do
     model
     |> cast(attrs, @required_fields)
     |> validate_required(@required_fields)
-    |> unique_constraint(:user_id)
   end
 end
diff --git a/lib/plausible/crm_extensions.ex b/lib/plausible/crm_extensions.ex
index 1ca27addf6de..054b6106f003 100644
--- a/lib/plausible/crm_extensions.ex
+++ b/lib/plausible/crm_extensions.ex
@@ -48,38 +48,71 @@ defmodule Plausible.CrmExtensions do
       ]
     end
 
-    def javascripts(%{assigns: %{context: context}})
-        when context in ["sites", "billing"] do
+    def javascripts(%{assigns: %{context: "billing", resource: "enterprise_plan", changeset: %{}}}) do
       [
         Phoenix.HTML.raw("""
         <script type="text/javascript">
-          (() => {
-            const publicField = document.querySelector("#kaffy-search-field")
-            const searchForm = document.querySelector("#kaffy-filters-form")
-            const searchField = document.querySelector("#kaffy-filter-search")
+          (async () => {
+            const CHECK_INTERVAL = 300
+            const userIdField = document.querySelector("#enterprise_plan_user_id")
+            const userIdLabel = document.querySelector("label[for=enterprise_plan_user_id]")
+            const dataList = document.createElement("datalist")
+            dataList.id = "user-choices"
+            userIdField.after(dataList)
+            userIdField.setAttribute("list", "user-choices")
+            userIdField.setAttribute("type", "text")
+            const labelSpan = document.createElement("span")
+            userIdLabel.appendChild(labelSpan)
+
+            let updateAction;
+
+            const updateLabel = async (id) => {
+              id = Number(id)
+
+              if (!isNaN(id) && id > 0) {
+                const response = await fetch(`/crm/billing/search/user-by-id/${id}`)
+                labelSpan.innerHTML = ` <i>(${await response.text()})</i>`
+              }
+            }
 
-            if (publicField && searchForm && searchField) {
-              publicField.name = "#{@custom_search}"
-              searchField.name = "#{@custom_search}"
+            const updateSearch = async () => {
+              const search = userIdField.value
 
-              const params = new URLSearchParams(window.location.search)
-              publicField.value = params.get("#{@custom_search}")
+              updateLabel(search)
 
-              const searchInput = document.createElement("input")
-              searchInput.name = "search"
-              searchInput.type = "hidden"
-              searchInput.value = ""
+              const response = await fetch("/crm/billing/search/user", {
+                headers: { "Content-Type": "application/json" },
+                method: "POST",
+                body: JSON.stringify({ search: search })
+              })
 
-              searchForm.appendChild(searchInput)
+              const list = await response.json()
+
+              const options =
+                list.map(([label, value]) => {
+                  const option = document.createElement("option")
+                  option.setAttribute("label", label)
+                  option.textContent = value
+
+                  return option
+                })
+
+              dataList.replaceChildren(...options)
             }
+
+            updateLabel(userIdField.value)
+
+            userIdField.addEventListener("input", async (e) => {
+              if (updateAction) {
+                clearTimeout(updateAction)
+                updateAction = null
+              }
+
+              updateAction = setTimeout(() => updateSearch(), CHECK_INTERVAL)
+            })
           })()
         </script>
-        """)
-      ]
-    end
-
-    def javascripts(%{assigns: %{context: "billing", resource: "enterprise_plan", changeset: %{}}}) do
-      [
+        """),
         Phoenix.HTML.raw("""
         <script type="text/javascript">
           (() => {
@@ -153,6 +186,36 @@ defmodule Plausible.CrmExtensions do
         """)
       ]
     end
+
+    def javascripts(%{assigns: %{context: context}})
+        when context in ["sites", "billing"] do
+      [
+        Phoenix.HTML.raw("""
+        <script type="text/javascript">
+          (() => {
+            const publicField = document.querySelector("#kaffy-search-field")
+            const searchForm = document.querySelector("#kaffy-filters-form")
+            const searchField = document.querySelector("#kaffy-filter-search")
+
+            if (publicField && searchForm && searchField) {
+              publicField.name = "#{@custom_search}"
+              searchField.name = "#{@custom_search}"
+
+              const params = new URLSearchParams(window.location.search)
+              publicField.value = params.get("#{@custom_search}")
+
+              const searchInput = document.createElement("input")
+              searchInput.name = "search"
+              searchInput.type = "hidden"
+              searchInput.value = ""
+
+              searchForm.appendChild(searchInput)
+            }
+          })()
+        </script>
+        """)
+      ]
+    end
   end
 
   def javascripts(_) do
diff --git a/lib/plausible_web/controllers/admin_controller.ex b/lib/plausible_web/controllers/admin_controller.ex
index e5a5c501b31c..69c6ef5f1cbd 100644
--- a/lib/plausible_web/controllers/admin_controller.ex
+++ b/lib/plausible_web/controllers/admin_controller.ex
@@ -2,6 +2,9 @@ defmodule PlausibleWeb.AdminController do
   use PlausibleWeb, :controller
   use Plausible
 
+  import Ecto.Query
+
+  alias Plausible.Repo
   alias Plausible.Teams
 
   def usage(conn, params) do
@@ -71,6 +74,60 @@ defmodule PlausibleWeb.AdminController do
     |> send_resp(200, json_response)
   end
 
+  def user_by_id(conn, params) do
+    id = params["user_id"]
+
+    entry =
+      Repo.one(
+        from u in Plausible.Auth.User,
+          where: u.id == ^id,
+          select: fragment("concat(?, ?, ?, ?)", u.name, " (", u.email, ")")
+      ) || ""
+
+    conn
+    |> send_resp(200, entry)
+  end
+
+  def user_search(conn, params) do
+    search =
+      (params["search"] || "")
+      |> String.trim()
+
+    choices =
+      if search != "" do
+        term =
+          search
+          |> String.replace("%", "\%")
+          |> String.replace("_", "\_")
+
+        term = "%#{term}%"
+
+        user_id =
+          case Integer.parse(search) do
+            {id, ""} -> id
+            _ -> 0
+          end
+
+        if user_id != 0 do
+          []
+        else
+          Repo.all(
+            from u in Plausible.Auth.User,
+              where: u.id == ^user_id or ilike(u.name, ^term) or ilike(u.email, ^term),
+              order_by: [u.name, u.id],
+              select: [fragment("concat(?, ?, ?, ?)", u.name, " (", u.email, ")"), u.id],
+              limit: 20
+          )
+        end
+      else
+        []
+      end
+
+    conn
+    |> put_resp_content_type("application/json")
+    |> send_resp(200, Jason.encode!(choices))
+  end
+
   defp usage_and_limits_html(team, usage, limits, embed?) do
     content = """
       <ul>
diff --git a/lib/plausible_web/router.ex b/lib/plausible_web/router.ex
index 2f9a882fc194..a03955599f7c 100644
--- a/lib/plausible_web/router.ex
+++ b/lib/plausible_web/router.ex
@@ -92,6 +92,8 @@ defmodule PlausibleWeb.Router do
       pipe_through :flags
       get "/auth/user/:user_id/usage", AdminController, :usage
       get "/billing/user/:user_id/current_plan", AdminController, :current_plan
+      get "/billing/search/user-by-id/:user_id", AdminController, :user_by_id
+      post "/billing/search/user", AdminController, :user_search
     end
   end