diff --git a/src/lib/stripe.ts b/src/lib/stripe.ts
index 30c001d..11b51d5 100644
--- a/src/lib/stripe.ts
+++ b/src/lib/stripe.ts
@@ -29,13 +29,13 @@
 import Stripe from "stripe";
 import type { Invoice } from "@/types";
 
-// Pinned API version. This is a string-literal type in the Stripe
-// SDK — the explicit `Stripe.LatestApiVersion` annotation forces a
-// compile error when the installed SDK ships with a different pin,
-// so a `npm update` that bumps Stripe to a new API version gets
-// caught here rather than at runtime. Bump this string deliberately
-// alongside the SDK upgrade and review the API changelog.
-const STRIPE_API_VERSION: Stripe.LatestApiVersion = "2026-04-22.dahlia";
+// Pinned API version. `as const` narrows this to a string-literal
+// type that the Stripe constructor's `apiVersion` field accepts
+// exactly. When the installed SDK bumps to a new pinned version,
+// TypeScript will surface the mismatch at the `new Stripe(...)` call
+// below — bump this string deliberately alongside the SDK upgrade
+// and review the API changelog before doing so.
+const STRIPE_API_VERSION = "2026-04-22.dahlia" as const;
 
 // Cache the client across hot reloads / serverless invocations.
 // We don't instantiate at module load because some build steps run