diff --git a/lib/Mojolicious/Plugin/Yancy.pm b/lib/Mojolicious/Plugin/Yancy.pm
index 5cbe6f76..da74eccc 100644
--- a/lib/Mojolicious/Plugin/Yancy.pm
+++ b/lib/Mojolicious/Plugin/Yancy.pm
@@ -585,6 +585,7 @@ sub _openapi_spec_infer_mojo {
         @{ $op_spec->{parameters} || [] },
         ;
     my ($id_field) = grep defined,
+        (map $_->{'x-id-field'}, $op_spec, $pathspec),
         (@path_params && $path_params[-1]{name});
     my %base_spec = (
         controller => $api_controller,
diff --git a/lib/Yancy/Help/Config.pod b/lib/Yancy/Help/Config.pod
index dce5e8d6..7c915cf7 100644
--- a/lib/Yancy/Help/Config.pod
+++ b/lib/Yancy/Help/Config.pod
@@ -461,9 +461,13 @@ an error. To derive which collection, these things are considered:
 
 Each operation infers from the HTTP method plus other information which
 method of L<Yancy::Controller::Yancy::API> it should connect to.
-The C<id_field> parameter is the C<name> of the last C<in: "path"> parameter
-specified in the operation's spec. Every operation type except C<get>
-in "list" mode, and C<post>, needs an C<id_field> parameter.
+
+The C<id_field> stash parameter is either the value of the C<x-id-field>
+key in the operation or path spec, or if not given, the C<name> of the
+last C<in: "path"> parameter specified in the operation's spec. Every
+operation type except C<get> in "list" mode, and C<post>, needs an
+C<id_field> parameter.  This is what the controller will pass as the C<id>
+to the relevant L<Yancy::Backend> method.
 
 =head1 Additional Configuration