diff --git a/t/Controller/Admin/clear-queue-non-current.t b/t/Controller/Admin/clear-queue-non-current.t
index 630abbdc..4669fb73 100644
--- a/t/Controller/Admin/clear-queue-non-current.t
+++ b/t/Controller/Admin/clear-queue-non-current.t
@@ -1,7 +1,7 @@
 use strict;
 use warnings;
 use Setup;
-use JSON qw(decode_json encode_json);
+use JSON::MaybeXS qw(decode_json encode_json);
 use File::Copy;
 
 my %ctx = test_init(
diff --git a/t/Controller/Build/cancel.t b/t/Controller/Build/cancel.t
index 5dc5ba8a..b2afc074 100644
--- a/t/Controller/Build/cancel.t
+++ b/t/Controller/Build/cancel.t
@@ -2,7 +2,7 @@ use feature 'unicode_strings';
 use strict;
 use warnings;
 use Setup;
-use JSON qw(decode_json encode_json);
+use JSON::MaybeXS qw(decode_json encode_json);
 
 my %ctx = test_init();
 
diff --git a/t/Controller/Build/restart.t b/t/Controller/Build/restart.t
index 75904ba4..9a993a11 100644
--- a/t/Controller/Build/restart.t
+++ b/t/Controller/Build/restart.t
@@ -2,7 +2,7 @@ use feature 'unicode_strings';
 use strict;
 use warnings;
 use Setup;
-use JSON qw(decode_json encode_json);
+use JSON::MaybeXS qw(decode_json encode_json);
 
 my %ctx = test_init();
 
diff --git a/t/Controller/JobsetEval/cancel.t b/t/Controller/JobsetEval/cancel.t
index 03f23e05..5b848117 100644
--- a/t/Controller/JobsetEval/cancel.t
+++ b/t/Controller/JobsetEval/cancel.t
@@ -2,7 +2,7 @@ use feature 'unicode_strings';
 use strict;
 use warnings;
 use Setup;
-use JSON qw(decode_json encode_json);
+use JSON::MaybeXS qw(decode_json encode_json);
 
 my %ctx = test_init();
 
diff --git a/t/Controller/JobsetEval/restart.t b/t/Controller/JobsetEval/restart.t
index c5957cf7..30581987 100644
--- a/t/Controller/JobsetEval/restart.t
+++ b/t/Controller/JobsetEval/restart.t
@@ -2,7 +2,7 @@ use feature 'unicode_strings';
 use strict;
 use warnings;
 use Setup;
-use JSON qw(decode_json encode_json);
+use JSON::MaybeXS qw(decode_json encode_json);
 
 my %ctx = test_init();
 
diff --git a/t/Controller/Root/narinfo.t b/t/Controller/Root/narinfo.t
index 297d336b..0a473a03 100644
--- a/t/Controller/Root/narinfo.t
+++ b/t/Controller/Root/narinfo.t
@@ -2,7 +2,7 @@ use strict;
 use warnings;
 use Setup;
 use Data::Dumper;
-use JSON qw(decode_json);
+use JSON::MaybeXS qw(decode_json);
 my %ctx = test_init(
   # Without this, the test will fail because a `file:` store is not treated as a
   # local store by `isLocalStore` in src/lib/Hydra/Helper/Nix.pm, and any
diff --git a/t/plugins/RunCommand/basic.t b/t/plugins/RunCommand/basic.t
index 4771e6af..0dfcd79d 100644
--- a/t/plugins/RunCommand/basic.t
+++ b/t/plugins/RunCommand/basic.t
@@ -1,7 +1,7 @@
 use feature 'unicode_strings';
 use strict;
 use warnings;
-use JSON;
+use JSON::MaybeXS;
 use Setup;
 
 my %ctx = test_init(
@@ -42,7 +42,7 @@ my $dat = do {
     open(my $json_fh, "<", $filename)
         or die("Can't open \"$filename\": $!\n");
     local $/;
-    my $json = JSON->new;
+    my $json = JSON::MaybeXS->new;
     $json->decode(<$json_fh>)
 };