diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index b8a9a9aa86e..5627e9d4cd3 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -7,9 +7,11 @@
 #include "nix/util/callback.hh"
 #include "nix/util/signals.hh"
 
+#include "nix/util/util.hh"
 #include "store-config-private.hh"
 #include "nix/store/s3-url.hh"
 #include <optional>
+#include <string_view>
 #if NIX_WITH_AWS_AUTH
 #  include "nix/store/aws-creds.hh"
 #endif
@@ -177,7 +179,7 @@ struct curlFileTransfer : public FileTransfer
 #if NIX_WITH_AWS_AUTH
             if (!request.awsSigV4Provider)
 #endif
-                appendHeaders("Accept-Encoding: zstd, br, gzip, deflate, bzip2, xz");
+                appendHeaders("Accept-Encoding: zstd, br, gzip, deflate, bzip2");
             if (!request.expectedETag.empty())
                 appendHeaders("If-None-Match: " + request.expectedETag);
             if (!request.mimeType.empty())
@@ -275,6 +277,29 @@ struct curlFileTransfer : public FileTransfer
                 result.urls.push_back(effectiveUriCStr);
         }
 
+        static std::string parseContentEncoding(std::string_view contentEncoding)
+        {
+
+            if (contentEncoding.find(",") != std::string::npos) {
+                throw nix::Error("Stacked Content-Encoding is not supported: %s", contentEncoding);
+            }
+
+            if (contentEncoding == "gzip" || contentEncoding == "x-gzip")
+                return "gzip";
+            else if (contentEncoding == "compress" || contentEncoding == "x-compress")
+                return "compress";
+            else if (contentEncoding == "br")
+                return "br";
+            else if (contentEncoding == "zstd")
+                return "zstd";
+            else if (contentEncoding == "bzip2")
+                return "bzip2";
+            else if (contentEncoding == "identity")
+                return "identity";
+
+            throw nix::Error("Invalid content-encoding: %s", contentEncoding);
+        }
+
         size_t headerCallback(void * contents, size_t size, size_t nmemb) noexcept
         try {
             size_t realSize = size * nmemb;
@@ -311,8 +336,11 @@ struct curlFileTransfer : public FileTransfer
                         }
                     }
 
+                    /* https://www.rfc-editor.org/rfc/rfc9110.html#name-content-codings
+                     * All content codings are case-insensitive and ought to be
+                     * registered within the "HTTP Content Coding Registry" */
                     else if (name == "content-encoding")
-                        encoding = trim(line.substr(i + 1));
+                        encoding = parseContentEncoding(toLower(trim(line.substr(i + 1))));
 
                     else if (name == "accept-ranges" && toLower(trim(line.substr(i + 1))) == "bytes")
                         acceptRanges = true;