[Home](./index.md) > [@snowplow/node-tracker](./node-tracker.md) > [EmitterConfigurationBase](./node-tracker.emitterconfigurationbase.md) > [cookieExtensionService](./node-tracker.emitterconfigurationbase.cookieextensionservice.md) ## EmitterConfigurationBase.cookieExtensionService property Cookie extension service full URL. This URL will be added to the queue and will be called using a GET method. This option is there to allow the service URL to be called in order to set any required identifiers e.g. extra cookies. The request respects the `anonymousTracking` option, including the SP-Anonymous header if needed, and any additional custom headers from the customHeaders option. Signature: ```typescript cookieExtensionService?: string; ```