diff --git a/.gitignore b/.gitignore
index c363d45..0587e4d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,6 @@ node_modules
 .DS_Store
 #src/**/*.js -- for tsc modules only, see https://github.com/hyperfiddle/photon/commit/0aa9b26c35d961151891c1e42ec13fcf52e38fa2
 /src-dev/fiddles.cljc
+# for xtdb-starter demo:
+data
+# ---
\ No newline at end of file
diff --git a/deps.edn b/deps.edn
index 0cd1bcc..08fb914 100644
--- a/deps.edn
+++ b/deps.edn
@@ -68,6 +68,13 @@
   {:extra-deps
    {com.datomic/peer {:mvn/version "1.0.7075"}}}
 
+  :xtdb-starter ; process must be started with `XTDB_ENABLE_BYTEUTILS_SHA1=true clj -A:xtdb-starter:...`
+  {:extra-deps
+   {com.xtdb/xtdb-core {:mvn/version "1.23.0"}
+    com.xtdb/xtdb-rocksdb {:mvn/version "1.23.0"}}
+   :jvm-opts [;; the following option is required for JDK 16 and 17 (https://github.com/xtdb/xtdb/issues/1462)
+              "--add-opens=java.base/java.util.concurrent=ALL-UNNAMED"]}
+
   :uix-demo
   {:extra-deps {com.pitch/uix.core {:mvn/version "1.0.1"}
                 com.pitch/uix.dom {:mvn/version "1.0.1"}}}
diff --git a/src/xtdb_starter/Readme.md b/src/xtdb_starter/Readme.md
new file mode 100644
index 0000000..2ba288e
--- /dev/null
+++ b/src/xtdb_starter/Readme.md
@@ -0,0 +1,18 @@
+This demo requires an environment variable to be set.
+
+Run a REPL:
+```shell
+XTDB_ENABLE_BYTEUTILS_SHA1=true clj -A:dev:xtdb-starter
+```
+At the REPL:
+```clojure
+(dev/-main)
+(dev/load-fiddle! 'xtdb-starter)
+```
+
+Build and run for prod:
+
+```shell
+clojure -X:build:prod:xtdb-starter build-client :hyperfiddle/domain xtdb-starter
+XTDB_ENABLE_BYTEUTILS_SHA1=true clj -M:prod:xtdb-starter -m prod
+```
diff --git a/src/xtdb_starter/fiddles.cljc b/src/xtdb_starter/fiddles.cljc
new file mode 100644
index 0000000..f2bb433
--- /dev/null
+++ b/src/xtdb_starter/fiddles.cljc
@@ -0,0 +1,41 @@
+(ns xtdb-starter.fiddles
+  (:require #?(:clj [clojure.java.io :as io])
+            #?(:clj [xtdb.api :as xt])
+            [hyperfiddle.electric-dom2 :as dom]
+            [hyperfiddle.electric :as e]
+            [xtdb-starter.todo-list :refer [Todo-list]]))
+
+#?(:clj (defonce !xtdb-node (atom nil)))
+
+#?(:clj
+   (defn start-xtdb! [] ; from XTDB’s getting started: xtdb-in-a-box
+     (assert (= "true" (System/getenv "XTDB_ENABLE_BYTEUTILS_SHA1"))) ; App must start with this env var set to "true"
+     (letfn [(kv-store [dir] {:kv-store {:xtdb/module 'xtdb.rocksdb/->kv-store
+                                         :db-dir (io/file dir)
+                                         :sync? true}})]
+       (or @!xtdb-node
+         (reset! !xtdb-node
+           (xt/start-node
+             {:xtdb/tx-log (kv-store "data/dev/tx-log")
+              :xtdb/document-store (kv-store "data/dev/doc-store")
+              :xtdb/index-store (kv-store "data/dev/index-store")}))))))
+
+(e/defn XTDB-Starter []
+  (e/server
+    (if-let [!xtdb (try (e/offload #(start-xtdb!))
+                          (catch hyperfiddle.electric.Pending _
+                            nil))]
+      (Todo-list. !xtdb)
+      (e/client
+        (dom/p (dom/text "XTDB is starting ..."))))))
+
+(e/def fiddles {`XTDB-Starter XTDB-Starter})
+
+(e/defn FiddleMain [ring-request]
+  (e/client
+    (binding [dom/node js/document.body]
+      (XTDB-Starter.))))
+
+(comment
+  (.close @!xtdb-node)
+  (reset! !xtdb-node nil))
diff --git a/src/xtdb_starter/todo_list.cljc b/src/xtdb_starter/todo_list.cljc
new file mode 100644
index 0000000..0fd714b
--- /dev/null
+++ b/src/xtdb_starter/todo_list.cljc
@@ -0,0 +1,83 @@
+(ns xtdb-starter.todo-list
+  (:require
+   #?(:clj [xtdb-starter.xtdb-contrib :as db])
+   [hyperfiddle.electric :as e]
+   [hyperfiddle.electric-dom2 :as dom]
+   [hyperfiddle.electric-ui4 :as ui]
+   [xtdb.api #?(:clj :as :cljs :as-alias) xt]))
+
+(e/def !xtdb)
+(e/def db) ; injected database ref; Electric defs are always dynamic
+
+(e/defn TodoItem [id]
+  (e/server
+    (let [e (xt/entity db id)
+          status (:task/status e)]
+      (e/client
+        (dom/div
+          (ui/checkbox
+            (case status :active false, :done true)
+            (e/fn [v]
+              (e/server
+                (e/discard
+                  (e/offload
+                    #(xt/submit-tx !xtdb [[:xtdb.api/put
+                                           {:xt/id id
+                                            :task/description (:task/description e) ; repeat
+                                            :task/status (if v :done :active)}]])))))
+            (dom/props {:id id}))
+          (dom/label (dom/props {:for id}) (dom/text (e/server (:task/description e)))))))))
+
+(e/defn InputSubmit [F]
+  ; Custom input control using lower dom interface for Enter handling
+  (e/client
+    (dom/input (dom/props {:placeholder "Buy milk"})
+      (dom/on "keydown" (e/fn [e]
+                          (when (= "Enter" (.-key e))
+                            (when-some [v (contrib.str/empty->nil (-> e .-target .-value))]
+                              (new F v)
+                              (set! (.-value dom/node) ""))))))))
+
+(e/defn TodoCreate []
+  (e/client
+    (InputSubmit. (e/fn [v]
+                    (e/server
+                      (e/discard
+                        (e/offload
+                          #(xt/submit-tx !xtdb [[:xtdb.api/put
+                                                 {:xt/id (random-uuid)
+                                                  :task/description v
+                                                  :task/status :active}]]))))))))
+
+#?(:clj
+   (defn todo-records [db]
+     (->> (xt/q db '{:find [(pull ?e [:xt/id :task/description])]
+                     :where [[?e :task/status]]})
+       (map first)
+       (sort-by :task/description)
+       vec)))
+
+#?(:clj
+   (defn todo-count [db]
+     (count (xt/q db '{:find [?e] :in [$ ?status]
+                       :where [[?e :task/status ?status]]}
+              :active))))
+
+(e/defn Todo-list [!xtdb]
+  (e/server
+    (binding [xtdb-starter.todo-list/!xtdb !xtdb
+              db (new (db/latest-db> !xtdb))]
+      (e/client
+        (dom/link (dom/props {:rel :stylesheet :href "/todo-list.css"}))
+        (dom/h1 (dom/text "minimal todo list"))
+        (dom/p (dom/text "it's multiplayer, try two tabs"))
+        (dom/div (dom/props {:class "todo-list"})
+          (TodoCreate.)
+          (dom/div {:class "todo-items"}
+            (e/server
+              (e/for-by :xt/id [{:keys [xt/id]} (e/offload #(todo-records db))]
+                (TodoItem. id))))
+          (dom/p (dom/props {:class "counter"})
+            (dom/span (dom/props {:class "count"})
+              (dom/text (e/server (e/offload #(todo-count db)))))
+            (dom/text " items left")))))))
diff --git a/src/xtdb_starter/xtdb_contrib.clj b/src/xtdb_starter/xtdb_contrib.clj
new file mode 100644
index 0000000..218759a
--- /dev/null
+++ b/src/xtdb_starter/xtdb_contrib.clj
@@ -0,0 +1,16 @@
+(ns xtdb-starter.xtdb-contrib
+  (:require [missionary.core :as m]
+            [xtdb.api :as xt]))
+
+(defn latest-db>
+  "return flow of latest XTDB tx, but only works for XTDB in-process mode. see
+  https://clojurians.slack.com/archives/CG3AM2F7V/p1677432108277939?thread_ts=1677430221.688989&cid=CG3AM2F7V"
+  [!xtdb]
+  (->> (m/observe (fn [!]
+                    (let [listener (xt/listen !xtdb {::xt/event-type ::xt/indexed-tx :with-tx-ops? true} !)]
+                      #(.close listener))))
+    (m/reductions {} (xt/latest-completed-tx !xtdb)) ; initial value is the latest known tx, possibly nil
+    (m/relieve {})
+    (m/latest (fn [{:keys [:xtdb.api/tx-time] :as ?tx}]
+                (if tx-time (xt/db !xtdb {::xt/tx-time tx-time})
+                    (xt/db !xtdb))))))