---
title: Fastly-Cookie-Overflow
summary: null
url: >-
  https://www.fastly.com/documentation/reference/http/http-headers/Fastly-Cookie-Overflow
---

When an inbound `Cookie` header attached to a request exceeds the maximum allowed length, it will be removed and `req.http.Cookie` will be empty.  The header `Fastly-Cookie-Overflow` will be set to `"1"` to allow this to be distinguished from a request that had no `Cookie` header in the first place.

The `Fastly-Cookie-Overflow` header is automatically removed from requests when they arrive on a Fastly server, before being set if the `Cookie` header is too long.  Therefore, in services that are configured to use [clustering](https://www.fastly.com/documentation/guides/vcl/clustering/), the header is present only in `vcl_recv` and `vcl_deliver`, and will not be present in requests made to backends.