diff --git a/cmd/packserver/main.go b/cmd/packserver/main.go
index 2000102..641a100 100644
--- a/cmd/packserver/main.go
+++ b/cmd/packserver/main.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync/atomic"
 	"syscall"
@@ -192,7 +193,7 @@ func run(c *cobra.Command, args []string) error {
 	}
 
 	// load packfiles, registering handlers as we go
-	var handler http.Handler
+	router := &routerHandler{}
 	for prefix, packfile := range packPaths {
 		packHandler, err := htpack.New(packfile)
 		if err != nil {
@@ -207,7 +208,7 @@ func run(c *cobra.Command, args []string) error {
 		}
 		packHandler.SetHeader("X-Frame-Options", framesHeader)
 
-		handler = &addHeaders{
+		var handler http.Handler = &addHeaders{
 			extraHeaders: extraHeaders,
 			handler:      packHandler,
 		}
@@ -215,12 +216,13 @@ func run(c *cobra.Command, args []string) error {
 		if prefix != "/" {
 			handler = http.StripPrefix(prefix, handler)
 		}
+		router.AddRoute(prefix, handler)
 	}
 
 	// HTTP server object setup
 	sv := &http.Server{
 		Addr:    bindAddr,
-		Handler: handler,
+		Handler: router,
 	}
 
 	// register SIGINT, SIGTERM handler
@@ -309,3 +311,53 @@ func (ah *addHeaders) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 	ah.handler.ServeHTTP(w, r)
 }
+
+// routeEntry is used within routerHandler to map a specific prefix to a
+// specific handler.
+type routeEntry struct {
+	// prefix is a path prefix with trailing "/" such as "/foo/".
+	prefix string
+
+	// handler for the request if prefix matches.
+	handler http.Handler
+}
+
+// routerHandler holds a list of routes sorted by longest-prefix-first.
+type routerHandler struct {
+	// entries are the list of prefixes, with longest prefix strings first.
+	// The sorting ensures we can iterate through from the start and match
+	// "/dir/subdir/" in preference to just "/dir/".
+	entries []routeEntry
+}
+
+// AddRoute adds a new entry into the handler. It is not concurrency safe; the
+// handler should not be in use.
+func (rh *routerHandler) AddRoute(prefix string, handler http.Handler) {
+	if !strings.HasSuffix(prefix, "/") {
+		prefix += "/"
+	}
+	rh.entries = append(rh.entries, routeEntry{
+		prefix:  prefix,
+		handler: handler,
+	})
+	sort.Slice(rh.entries, func(i, j int) bool {
+		l1, l2 := len(rh.entries[i].prefix), len(rh.entries[j].prefix)
+		if l1 > l2 {
+			return true
+		}
+		if l1 == l2 {
+			return rh.entries[i].prefix < rh.entries[j].prefix
+		}
+		return false
+	})
+}
+
+func (rh *routerHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	for _, entry := range rh.entries {
+		if strings.HasPrefix(r.URL.Path, entry.prefix) {
+			entry.handler.ServeHTTP(w, r)
+			return
+		}
+	}
+	http.NotFound(w, r)
+}