diff --git a/play/src/sht/ninjagen.clj b/play/src/sht/ninjagen.clj
new file mode 100644
index 00000000..373819b4
--- /dev/null
+++ b/play/src/sht/ninjagen.clj
@@ -0,0 +1,315 @@
+(ns sht.ninjagen
+  (:require [clojure.string :as str]
+            [babashka.fs :as fs]
+            [babashka.process :as p]))
+
+(defn- indent
+  [lines]
+  (map (partial str "  ") lines))
+
+(defn- gen-vars
+  [m]
+  (->> m
+       (map (fn [[k v]]
+              [(name k) (str v)]))
+       sort
+       (mapv (fn [[k v]]
+               (format "%s = %s" k v)))))
+
+(defn gen
+  [ds]
+  (cond
+    (map? ds)
+      (gen-vars ds)
+    (string? ds)
+      [ds]
+    (nil? ds)
+      []
+    :else
+      (mapcat gen ds)))
+
+(defn- format-path
+  [p]
+  (str/replace (str p) " " "$ "))
+
+(defn- format-paths
+  [ps]
+  (if (string? ps)
+    (format-path ps)
+    (str/join " " (map format-path ps))))
+
+(defn rule
+  [rule-name & {:as vars}]
+  [(str "rule " rule-name)
+   (indent (gen-vars vars))
+   ""])
+
+(defn build
+  [rule & {:keys [outputs inputs implicit-deps vars]}]
+  [(str "build " (format-paths outputs) ": "
+        (name rule) " " (format-paths inputs)
+        (when (seq implicit-deps) (str " | " (format-paths implicit-deps))))
+   (indent (gen vars))
+   ""])
+
+(defn gen-file
+  [ds path]
+  (let [lines (remove nil? (gen ds))
+        ninja-str (str/join (interleave lines (repeat \newline)))]
+    (spit path ninja-str)))
+
+(def absnormpath (comp str fs/absolutize fs/normalize fs/path))
+
+(def rule-npm-install
+  (rule "npm-install" {:command "cd $src-dir; npm install; touch $mark-path"
+                       :description "Running npm install in $src-dir"}))
+
+(defn build-npm-project
+  [src-dir & {:keys [alias]}]
+  (let [implicit-deps [(absnormpath src-dir "package.json")
+                       (absnormpath src-dir "package-lock.json")]
+        mark-path (absnormpath src-dir "node_modules/.mark-npm-install")]
+    [(build "npm-install"
+            :outputs [mark-path]
+            :implicit-deps implicit-deps
+            :vars {:src-dir src-dir
+                   :mark-path mark-path})
+     (when-not (empty? alias)
+       (build "phony" :outputs [alias] :inputs [mark-path]))]))
+
+
+(defn go-files
+  [src-dir]
+  (->> (p/process ["go" "list" "-m" "-f={{.Dir}}"]
+                  {:out :string
+                   :err :string
+                   :dir src-dir})
+       p/check
+       :out
+       str/split-lines
+       (mapcat (fn [dir]
+                 (concat (map str (fs/glob dir "go.{mod,sum}"))
+                         (sort (map str (fs/glob dir "**.go"))))))))
+
+(def go-code-generators
+  ["github.com/deepmap/oapi-codegen/cmd/oapi-codegen@v1.9.1"
+   "github.com/sqlc-dev/sqlc/cmd/sqlc@v1.22.0"
+   "google.golang.org/protobuf/cmd/protoc-gen-go@v1.30.0"
+   "github.com/abice/go-enum@v0.5.6"
+   "github.com/ethereum/go-ethereum/cmd/abigen@v1.12.0"])
+
+(def rule-oapi-codegen
+  ["# Run oapi-codegen"
+   (rule "oapi-codegen"
+         :command "$oapi-codegen --generate $generate --package $package -o $out $in")])
+
+(def rule-sqlc
+  ["# Run sqlc generate"
+   (rule "sqlc"
+         :command "$sqlc generate --file $in")])
+
+(def rule-protoc
+  ["# Run protoc"
+   (rule "protoc"
+         :command "$protoc --plugin $protoc-gen-go -I${go-out} $basename --go_out ${go-out}")])
+
+(defn build-oapi-codegen
+  [& {:keys [package inputs outputs generate implicit-deps]}]
+  (build "oapi-codegen"
+         :inputs inputs
+         :outputs outputs
+         :implicit-deps implicit-deps
+         :vars {:package package
+                :generate generate}))
+
+(defn- pkg-exe-name
+  [pkg]
+  (second (re-find #"/([^/@]+)(@[^/]*)?$", pkg)))
+
+(def rule-go-install
+  (rule "go-install"
+        :command "env GOBIN=${dst-dir} go install $pkg"
+        :description "Install $pkg to $dst-dir"))
+
+(defn build-go
+  [src-dir & {:keys [dst-dir executables subdirs alias]}]
+  (let [executables (mapv (fn [e] (str (fs/path dst-dir e))) executables)]
+    [(build "go-build"
+            :outputs executables
+            :implicit-deps (map str (go-files src-dir))
+            :vars {:src-dir src-dir
+                   :dst-dir dst-dir
+                   :subdirs (str/join " " subdirs)})
+     (when-not (empty? alias)
+       (build "phony" :outputs [alias] :inputs executables))]))
+
+(def go-rules
+  ["# Build go projects"
+   (rule "go-build"
+         :command "$go build -C $src-dir -o $dst-dir $subdirs")
+   "# Install go package"
+   (rule "go-install"
+         :command "env GOBIN=${dst-dir} go install $pkg"
+         :description "Install $pkg to $dst-dir")])
+
+(defn go-install
+  [pkg & {:keys [dst-dir]}]
+  (build "go-install" :outputs [(str (fs/path dst-dir (pkg-exe-name pkg)))]
+         :vars {:pkg pkg
+                :dst-dir (absnormpath dst-dir)}))
+
+(defn build-sqlc
+  [path & {:keys [implicit-deps]}]
+  (let [path (fs/absolutize path)
+        ;;yml-data (slurp-yml (str path))
+        sql-files (fs/glob (fs/parent path) "**.sql")]
+    (build "sqlc"
+           :outputs [(fs/normalize (fs/path path "../../models.sqlc.gen.go"))]
+           :inputs [(str path)]
+           :implicit-deps (concat implicit-deps
+                                  (sort (map str sql-files))))))
+
+(defn build-protoc
+  [path & {:keys [implicit-deps]}]
+  (let [dir (str (fs/parent path))]
+    (build "protoc"
+           :outputs [(str (fs/strip-ext path) ".pb.go")]
+           :inputs (str path)
+           :implicit-deps implicit-deps
+           :vars {:go-out dir
+                  :basename (fs/file-name path)})))
+
+(defn configure-oapi
+  [{:keys [shutter-root install-code-generators? run-code-generators? dst-dir]}]
+  (let [oapi-codegen (if install-code-generators? (absnormpath dst-dir "oapi-codegen") "oapi-codegen")
+
+        implicit-deps (if install-code-generators? [(absnormpath oapi-codegen)] [])]
+    ["#"
+     "# --- oapi-codegen"
+     "#"
+     {:oapi-codegen oapi-codegen}
+     ""
+     rule-oapi-codegen
+     (build-oapi-codegen :package "client"
+                         :generate "types,client"
+                         :inputs (absnormpath shutter-root "collator/oapi/oapi.yaml")
+                         :outputs (absnormpath shutter-root "collator/client/client.gen.go")
+                         :implicit-deps implicit-deps)
+     (build-oapi-codegen :package "oapi"
+                         :generate "types,chi-server,spec"
+                         :inputs (absnormpath shutter-root "collator/oapi/oapi.yaml")
+                         :outputs (absnormpath shutter-root "collator/oapi/oapi.gen.go")
+                         :implicit-deps implicit-deps)
+     (build-oapi-codegen :package "kproapi"
+                         :generate "types,chi-server,spec"
+                         :inputs (absnormpath shutter-root "keyper/kproapi/oapi.yaml")
+                         :outputs (absnormpath shutter-root "keyper/kproapi/oapi.gen.go")
+                         :implicit-deps implicit-deps)]))
+
+(defn configure-abigen
+  [{:keys [shutter-root install-code-generators? dst-dir]}]
+  (let [contracts-dir (absnormpath shutter-root "../contracts")
+        sol-files (fs/glob contracts-dir "src/**/*.sol")
+        abigen (if install-code-generators? (absnormpath dst-dir "abigen") "abigen")
+        abigen-js (fs/path contracts-dir "scripts" "abigen.js")
+        command (if install-code-generators?
+                  (str "env PATH=\"" (absnormpath dst-dir) ":$$PATH\" node " abigen-js)
+                  (str "node " abigen-js))
+        implicit-deps (if install-code-generators? [(absnormpath abigen)] [])
+        implicit-deps (concat implicit-deps
+                              ["contracts" abigen-js])]
+    ["# --- abigen"
+     ""
+     {:abigen abigen}
+     ""
+     (rule "abigen"
+           :command command
+           :description "Running abigen")
+     ""
+     (build "abigen"
+            :outputs [(fs/path contracts-dir "combined.json")
+                      (fs/path shutter-root "contract/binding.abigen.gen.go")]
+            :inputs sol-files
+            :implicit-deps implicit-deps)
+
+     ]
+    ))
+
+(defn configure-sqlc
+  [{:keys [shutter-root install-code-generators? dst-dir]}]
+  (let [sqlc-yaml-paths (fs/glob shutter-root "**/sqlc.yaml")
+        sqlc (if install-code-generators? (absnormpath dst-dir "sqlc") "sqlc")
+        implicit-deps (if install-code-generators? [sqlc] [])]
+    ["# --- sqlc"
+     ""
+     {:sqlc sqlc}
+     ""
+     rule-sqlc
+     (for [path sqlc-yaml-paths]
+       (build-sqlc path :implicit-deps implicit-deps))]))
+
+(defn configure-protoc
+  [{:keys [shutter-root install-code-generators? dst-dir]}]
+  (let [proto-paths (fs/glob shutter-root "**/*.proto")
+        protoc-gen-go (if install-code-generators? (absnormpath dst-dir "protoc-gen-go") (fs/which "protoc-gen-go"))
+        implicit-deps (if install-code-generators? [protoc-gen-go] [])]
+    ["# --- protoc"
+     ""
+     {:protoc "protoc"
+      :protoc-gen-go protoc-gen-go}
+
+     rule-protoc
+     (for [path proto-paths]
+       (build-protoc path :implicit-deps implicit-deps))]))
+
+(defn configure-code-generators
+  [{:keys [dst-dir]}]
+  (for [pkg go-code-generators]
+    (go-install pkg :dst-dir dst-dir)))
+
+(defn configure-rolling-shutter
+  [{:keys [shutter-root dst-dir]}]
+  ["# --- rolling-shutter"
+   (build-go (str shutter-root)
+             :dst-dir dst-dir
+             :executables ["rolling-shutter" "keygen"]
+             :subdirs ["." "./sandbox/keygen"]
+             :alias "rolling-shutter")
+   ;; (build "phony" :outputs ["rolling-shutter"] :inputs [(absnormpath dst-dir "rolling-shutter")])
+   "default rolling-shutter"
+   ""])
+
+(defn configure-contracts
+  [env]
+  (build-npm-project (absnormpath (:shutter-root env) "../contracts") :alias "contracts"))
+
+(defn dump-env
+  [env]
+  (map (fn [[k v]] (format  "# %28s  %s" k v)) env))
+
+(defn configure
+  [{:keys [install-code-generators? run-code-generators? dst-dir] :as env}]
+  ["# Please do not edit this file"
+   "#"
+   (dump-env env)
+   ""
+   {:go "go"
+    :dst-dir dst-dir}
+   ""
+   go-rules
+
+   (when run-code-generators?
+     [(configure-oapi env)
+      (configure-sqlc env)
+      (configure-protoc env)
+      (configure-abigen env)])
+
+   (when install-code-generators?
+     (configure-code-generators env))
+
+   (configure-rolling-shutter env)
+
+   rule-npm-install
+   (configure-contracts env)
+
+   "# build.ninja ends here"])
diff --git a/rolling-shutter/.gitignore b/rolling-shutter/.gitignore
index 48c2ef12..4b123f5a 100644
--- a/rolling-shutter/.gitignore
+++ b/rolling-shutter/.gitignore
@@ -9,3 +9,5 @@
 /godoc.idx
 /go.work
 /go.work.sum
+/build.ninja
+/.ninja_*
diff --git a/rolling-shutter/build.clj b/rolling-shutter/build.clj
new file mode 100755
index 00000000..35973699
--- /dev/null
+++ b/rolling-shutter/build.clj
@@ -0,0 +1,56 @@
+#!/usr/bin/env bb
+
+(require '[babashka.classpath :as cp]
+         '[babashka.process :as p]
+         '[babashka.cli :as cli]
+         '[babashka.fs :as fs])
+
+(let [src-dir (str (fs/normalize (fs/absolutize (fs/path *file* "../../play/src"))))]
+  (cp/add-classpath src-dir))
+
+(require '[sht.ninjagen :as n])
+
+(def spec
+  {:gen
+   {:desc "Whether to run code generators"
+    :default true}
+
+   :install-gen
+   {:desc "Whether to install code generators"
+    :default true}
+
+   :run-ninja
+   {:desc "Run ninja"
+    :alias :x}
+
+   :help
+   {:desc "Show help message"
+    :alias :h}})
+
+(defn print-help
+  []
+  (println "Usage: build.clj [options]")
+  (println (cli/format-opts {:spec spec :order [:gen :install-gen :run-ninja :help]}))
+  (System/exit 0))
+
+(defn -main [& args]
+  (let [{:keys [help gen install-gen run-ninja]} (cli/parse-opts args
+                                                                 {:spec spec
+                                                                  :restrict (keys spec)})
+        shutter-root (n/absnormpath *file* "..")
+        build-ninja (n/absnormpath *file* ".." "build.ninja")]
+    (when help
+      (print-help))
+    ;; (println "Generating"  build-ninja)
+    (-> {:shutter-root shutter-root
+         :install-code-generators? install-gen
+         :run-code-generators? gen
+         :dst-dir (n/absnormpath *file* "../bin")}
+        n/configure
+        (n/gen-file build-ninja))
+    (when run-ninja
+      (p/check (p/process {:out :inherit :err :inherit :in :inherit}
+                          "ninja" "-C" shutter-root)))))
+
+(when (= *file* (System/getProperty "babashka.file"))
+  (apply -main *command-line-args*))