No signatures found matching the expected signature

StripeSignatureVerificationError: No signatures found matching the expected signature for payload. Are you passing the raw request body you received from Stripe?

// src/app/api/stripe/webhook/route.ts
import Stripe from "stripe";

export const runtime = "nodejs";

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!);

export async function POST(req: Request) {
  const sig = req.headers.get("stripe-signature");
  if (!sig) return new Response("Missing signature", { status: 400 });
  const body = await req.text(); // raw body: never req.json()
  let event: Stripe.Event;
  try {
    event = stripe.webhooks.constructEvent(body, sig, process.env.STRIPE_WEBHOOK_SECRET!);
  } catch (err) {
    return new Response(`Invalid signature: ${(err as Error).message}`, { status: 400 });
  }
  // ...handle event.type...
  return Response.json({ received: true });
}

My Stripe webhook fails with 'No signatures found matching the expected signature'. Open src/app/api/stripe/webhook/route.ts and make sure the body is read once with await req.text() and passed unmodified to stripe.webhooks.constructEvent with the stripe-signature header. Remove any req.json(), JSON.stringify or body-parsing wrapper before verification. Don't change the event handling.