General size limits - Cookies, headers, URLs

  • Total cookie header size can be up to 32K in length

  • The maximum size to all headers combined is half the workspace so: 64K

  • Maximum size of headers on a synthetic is 1K, and that includes old values of headers, not just the end result

  • Maximum number of headers is 96, for both request and reply. However, some are reserved for internal use so the practical limit is around 85

  • The limit on URL size is 4095, since most browsers only do 2K

Useful variables to log
Snowplow Analytics and log streaming into BigQuery for real-time dashboards?

VCL file size limit is also 64k right now.


The URL size has been increased since then to 8KB.