diff --git a/hydra-api.yaml b/hydra-api.yaml
index 6b67a9fe..a2fb1bc3 100644
--- a/hydra-api.yaml
+++ b/hydra-api.yaml
@@ -688,18 +688,6 @@ components:
         'type':
           description: The type of this input
           type: string
-          enum:
-            - bzr
-            - bzr-checkout
-            - bitbucketpulls
-            - darcs
-            - git
-            - githubpulls
-            - gitlabpulls
-            - hg
-            - path
-            - svn
-            - svn-checkout
         revision:
           nullable: true
           description: A Git/Mercurial commit hash or a Subversion revision number.
diff --git a/src/lib/Hydra/Controller/Jobset.pm b/src/lib/Hydra/Controller/Jobset.pm
index 24776994..ae0bb018 100644
--- a/src/lib/Hydra/Controller/Jobset.pm
+++ b/src/lib/Hydra/Controller/Jobset.pm
@@ -213,6 +213,22 @@ sub checkInputValue {
 }
 
 
+sub knownInputTypes {
+    my ($c) = @_;
+
+    my @keys = keys %{$c->stash->{inputTypes}};
+    my $types = "";
+    my $counter = 0;
+
+    foreach my $key (@keys) {
+        $types = $types . "and ‘$key’" if ++$counter == scalar(@keys);
+        $types = $types . "‘$key’, " if $counter != scalar(@keys);
+    }
+
+    return $types;
+}
+
+
 sub updateJobset {
     my ($c, $jobset) = @_;
 
@@ -275,9 +291,10 @@ sub updateJobset {
             my $type = $inputData->{type};
             my $value = $inputData->{value};
             my $emailresponsible = defined $inputData->{emailresponsible} ? 1 : 0;
+            my $types = knownInputTypes($c);
 
-            error($c, "Invalid input name ‘$name’.") unless $name =~ /^[[:alpha:]][\w-]*$/;
-            error($c, "Invalid input type ‘$type’.") unless defined $c->stash->{inputTypes}->{$type};
+            badRequest($c, "Invalid input name ‘$name’.") unless $name =~ /^[[:alpha:]][\w-]*$/;
+            badRequest($c, "Invalid input type ‘$type’; valid types: $types.") unless defined $c->stash->{inputTypes}->{$type};
 
             my $input = $jobset->jobsetinputs->create(
                 { name => $name,
diff --git a/t/Controller/Jobset/http.t b/t/Controller/Jobset/http.t
index dc11c7a2..be2950f0 100644
--- a/t/Controller/Jobset/http.t
+++ b/t/Controller/Jobset/http.t
@@ -157,6 +157,36 @@ subtest 'Update jobset "job" to legacy type' => sub {
 };
 
 
+subtest 'Update jobset "job" to have an invalid input type' => sub {
+  my $jobsetupdate = request(PUT '/jobset/tests/job',
+      Accept => 'application/json',
+      Content_Type => 'application/json',
+      Cookie => $cookie,
+      Content => encode_json({
+        enabled => 3,
+        visible => JSON::true,
+        name => "job",
+        type => 0,
+        nixexprinput => "ofborg",
+        nixexprpath => "release.nix",
+        inputs => {
+          ofborg => {
+            name => "ofborg",
+            type => "123",
+            value => "https://github.com/NixOS/ofborg.git released"
+          }
+        },
+        description => "test jobset",
+        checkinterval => 0,
+        schedulingshares => 50,
+        keepnr => 1
+      })
+  );
+  ok(!$jobsetupdate->is_success);
+  ok($jobsetupdate->content =~ m/Invalid input type.*valid types:/);
+};
+
+
 subtest 'Delete jobset "job"' => sub {
   my $jobsetinfo = request(DELETE '/jobset/tests/job',
       Accept => 'application/json',