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.