diff --git a/cachix-api.cabal b/cachix-api.cabal
--- a/cachix-api.cabal
+++ b/cachix-api.cabal
@@ -1,6 +1,6 @@
 cabal-version:   2.2
 name:            cachix-api
-version:         1.11.1
+version:         1.12.0
 synopsis:        Servant HTTP API specification for https://cachix.org
 homepage:        https://github.com/cachix/cachix#readme
 bug-reports:     https://github.com/cachix/cachix/issues
diff --git a/src/Cachix/API.hs b/src/Cachix/API.hs
--- a/src/Cachix/API.hs
+++ b/src/Cachix/API.hs
@@ -47,7 +47,8 @@
           :> "cache"
           :> Capture "name" Text
           :> Capture "narinfohash" NarInfoHash.NarInfoHash
-          :> Get '[XNixNarInfo, JSON] (Headers '[Header "Cache-Control" Text] NarInfo.CachixNarInfo),
+          :> Header "If-None-Match" Text
+          :> Get '[XNixNarInfo, JSON] (Headers '[Header "ETag" Text, Header "Cache-Control" Text] NarInfo.CachixNarInfo),
     narinfoHead ::
       route
         :- CachixAuth