diff --git a/module/web/client.scm b/module/web/client.scm
index 4da361ab7..3f6c45bfe 100644
--- a/module/web/client.scm
+++ b/module/web/client.scm
@@ -41,6 +41,8 @@
   #:use-module (web uri)
   #:use-module (web http)
   #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-9 gnu)
   #:export (current-http-proxy
             open-socket-for-uri
             http-get
@@ -103,14 +105,9 @@
               (loop (cdr addresses))))))))
 
 (define (extend-request r k v . additional)
-  (let ((r (build-request (request-uri r)
-                          #:method (request-method r)
-                          #:version (request-version r)
-                          #:headers
-                          (assoc-set! (copy-tree (request-headers r))
-                                      k v)
-                          #:port (request-port r)
-                          #:meta (request-meta r))))
+  (let ((r (set-field r (request-headers)
+                      (assoc-set! (copy-tree (request-headers r))
+                                  k v))))
     (if (null? additional)
         r
         (apply extend-request r additional))))
diff --git a/module/web/server.scm b/module/web/server.scm
index bc204808d..99196faf9 100644
--- a/module/web/server.scm
+++ b/module/web/server.scm
@@ -74,6 +74,7 @@
 
 (define-module (web server)
   #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-9 gnu)
   #:use-module (rnrs bytevectors)
   #:use-module (ice-9 binary-ports)
   #:use-module (web request)
@@ -164,12 +165,9 @@ values."
    #:post-error (lambda _ (values #f #f #f))))
 
 (define (extend-response r k v . additional)
-  (let ((r (build-response #:version (response-version r)
-                           #:code (response-code r)
-                           #:headers
-                           (assoc-set! (copy-tree (response-headers r))
-                                       k v)
-                           #:port (response-port r))))
+  (let ((r (set-field r (response-headers)
+                      (assoc-set! (copy-tree (response-headers r))
+                                  k v))))
     (if (null? additional)
         r
         (apply extend-response r additional))))