diff --git a/pkgs/by-name/ke/keycastr/package.nix b/pkgs/by-name/ke/keycastr/package.nix
index 8259a8bb400d..5eca502af147 100644
--- a/pkgs/by-name/ke/keycastr/package.nix
+++ b/pkgs/by-name/ke/keycastr/package.nix
@@ -24,6 +24,8 @@ stdenvNoCC.mkDerivation (finalAttrs: {
     runHook postInstall
   '';
 
+  passthru.updateScript = ./update.sh;
+
   meta = {
     homepage = "https://github.com/keycastr/keycastr";
     description = "Open-source keystroke visualizer";
diff --git a/pkgs/by-name/ke/keycastr/update.sh b/pkgs/by-name/ke/keycastr/update.sh
new file mode 100755
index 000000000000..b564ff9f52e0
--- /dev/null
+++ b/pkgs/by-name/ke/keycastr/update.sh
@@ -0,0 +1,20 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p curl jq gnused
+
+set -euo pipefail
+
+cd "$(dirname "$0")" || exit 1
+
+# Grab latest release version
+LATEST_VER="$(curl --fail -s ${GITHUB_TOKEN:+-u ":$GITHUB_TOKEN"} "https://api.github.com/repos/keycastr/keycastr/releases/latest" | jq -r '.tag_name' | sed 's/^v//')"
+CURRENT_VER="$(grep -oP 'version = "\K[^"]+' package.nix)"
+
+if [[ "$LATEST_VER" == "$CURRENT_VER" ]]; then
+    echo "keycastr is up-to-date"
+    exit 0
+fi
+
+HASH="$(nix-hash --to-sri --type sha256 "$(nix-prefetch-url --type sha256 "https://github.com/keycastr/keycastr/releases/download/v${LATEST_VER}/KeyCastr.app.zip")")"
+
+sed -i "s#hash = \".*\"#hash = \"$HASH\"#g" package.nix
+sed -i "s#version = \".*\";#version = \"$LATEST_VER\";#g" package.nix