The HPACK spec [1] remarks on this. Google carefully used DEFLATE in earlier SPDY versions [2] but HTTP/2 decided to be less clever. Interestingly, SLZ's page

The HPACK spec [1] remarks on this. Google carefully used DEFLATE in earlier SPDY versions [2] but HTTP/2 decided to be less clever. Interestingly, SLZ's page comments on lack of history as a way to avoid CRIME attacks, which is one of the things the HTTP/2 people worried about. That seems like something it'd be easy for an implementation to screw up though (just add some buffering somewhere before the compressor...) [1] https://http2.github.io/http2-spec/compression.html#rfc.section.1 https://http2.github.io/http2-spec/compression.html#rfc.sect... [2] https://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3#TOC-2.6.10.1-Compression https://www.chromium.org/spdy/spdy-protocol/spdy-protocol-dr...