diff --git a/web/migrations/004_add_bigint_signals.js b/web/migrations/004_add_bigint_signals.js
new file mode 100644
index 0000000..9ad50a5
--- /dev/null
+++ b/web/migrations/004_add_bigint_signals.js
@@ -0,0 +1,12 @@
+/** @type {import('node-pg-migrate').MigrationBuilder} */
+exports.up = (pgm) => {
+  pgm.sql(`ALTER TABLE signals ALTER COLUMN green TYPE bigint`);
+  pgm.sql(`ALTER TABLE signals ALTER COLUMN red TYPE bigint`);
+  pgm.sql(`ALTER TABLE alerts ALTER COLUMN threshold TYPE bigint`);
+};
+
+exports.down = (pgm) => {
+  pgm.sql(`ALTER TABLE alerts ALTER COLUMN threshold TYPE integer`);
+  pgm.sql(`ALTER TABLE signals ALTER COLUMN red TYPE integer`);
+  pgm.sql(`ALTER TABLE signals ALTER COLUMN green TYPE integer`);
+};