diff --git a/collects/unstable/bytes.rkt b/collects/unstable/bytes.rkt
index daf1e39e92..ecb1264d57 100644
--- a/collects/unstable/bytes.rkt
+++ b/collects/unstable/bytes.rkt
@@ -1,19 +1,9 @@
 #lang racket/base
-(require racket/contract/base
-         racket/serialize)
+(require racket/contract/base)
 
 (provide/contract
- [read/bytes (bytes? . -> . serializable?)]
- [write/bytes (serializable? . -> . bytes?)]
- [bytes-ci=? (bytes? bytes? . -> . boolean?)])
-
-(define (bytes-ci=? b0 b1)
-  (string-ci=? (bytes->string/utf-8 b0)
-               (bytes->string/utf-8 b1)))
-;; Eli: If this ever gets in, it should say that the memory requirements
-;;   are 4 times the input size, especially since bytes are often used to save
-;;   space.  Also, fails on (bytes-ci=? #"\277" #"\277"), and a trivial fix
-;;   would still fail on (bytes-ci=? #"\276\277" #"\277\276")
+ [read/bytes (bytes? . -> . printable/c)]
+ [write/bytes (printable/c . -> . bytes?)])
 
 (define (read/bytes bs)
   (read (open-input-bytes bs)))
diff --git a/collects/unstable/scribblings/bytes.scrbl b/collects/unstable/scribblings/bytes.scrbl
index 40616456d6..e0ef8321c5 100644
--- a/collects/unstable/scribblings/bytes.scrbl
+++ b/collects/unstable/scribblings/bytes.scrbl
@@ -1,6 +1,6 @@
 #lang scribble/doc
 @(require scribble/base scribble/manual "utils.rkt"
-          (for-label racket/base unstable/bytes racket/serialize
+          (for-label racket/base unstable/bytes
                      racket/contract))
 
 @title[#:tag "bytes"]{Bytes}
@@ -9,16 +9,12 @@
 
 @unstable-header[]
 
-@defproc[(bytes-ci=? [b1 bytes?] [b2 bytes?]) boolean?]{
- Compares two bytes case insensitively.
-}
-
 @defproc[(read/bytes [b bytes?])
-         serializable?]{
+         printable/c]{
  @racket[read]s a value from @racket[b] and returns it.
 }
 
-@defproc[(write/bytes [v serializable?])
+@defproc[(write/bytes [v printable/c])
          bytes?]{
  @racket[write]s @racket[v] to a bytes and returns it.
 }
diff --git a/collects/web-server/private/util.rkt b/collects/web-server/private/util.rkt
index 6e8ac6b199..1d563653ae 100644
--- a/collects/web-server/private/util.rkt
+++ b/collects/web-server/private/util.rkt
@@ -16,6 +16,19 @@
 
 ;; --
 
+(define (bytes-ci=? b0 b1)
+  (string-ci=? (bytes->string/utf-8 b0)
+               (bytes->string/utf-8 b1)))
+;; Eli: If this ever gets in, it should say that the memory requirements
+;;   are 4 times the input size, especially since bytes are often used to save
+;;   space.  Also, fails on (bytes-ci=? #"\277" #"\277"), and a trivial fix
+;;   would still fail on (bytes-ci=? #"\276\277" #"\277\276")
+
+(provide/contract
+ [bytes-ci=? (bytes? bytes? . -> . boolean?)])
+
+;; --
+
 ;; network-error: symbol string . values -> void
 ;; throws a formatted exn:fail:network
 (define (network-error src fmt . args)