diff --git a/guix-data-service/web/server.scm b/guix-data-service/web/server.scm
index 6818258..f4430d2 100644
--- a/guix-data-service/web/server.scm
+++ b/guix-data-service/web/server.scm
@@ -203,6 +203,9 @@ port. Also, the port used can be changed by passing the --port option.\n"
                        #:destructor
                        (lambda (conn)
                          (close-postgresql-connection conn "web"))
+                       #:default-max-waiters 300
+                       #:default-checkout-timeout (/ postgresql-statement-timeout
+                                                     1000)
                        #:scheduler priority-scheduler))
 
                      (reserved-connection-pool
@@ -263,7 +266,10 @@ port. Also, the port used can be changed by passing the --port option.\n"
 
                              (let ((path-components
                                     mime-types
-                                    (request->path-components-and-mime-type request)))
+                                    (request->path-components-and-mime-type request))
+                                   (pool-exn?
+                                    (or (resource-pool-timeout-error? exn)
+                                        (resource-pool-too-many-waiters-error? exn))))
                                (case (most-appropriate-mime-type
                                       mime-types
                                       '(text/html application/json))
@@ -273,7 +279,9 @@ port. Also, the port used can be changed by passing the --port option.\n"
                                    (render-json `((error . ,(if (%show-error-details)
                                                                 (simple-format #f "~A" exn)
                                                                 #f)))
-                                                #:code 500)))
+                                                #:code (if pool-exn?
+                                                           503
+                                                           500))))
                                  (else
                                   (apply
                                    values
@@ -281,7 +289,9 @@ port. Also, the port used can be changed by passing the --port option.\n"
                                                         (if (%show-error-details)
                                                             exn
                                                             #f))
-                                                #:code 500))))))
+                                                #:code (if pool-exn?
+                                                           503
+                                                           500)))))))
                          (lambda ()
                            (with-exception-handler
                                (lambda (exn)