diff --git a/flake.lock b/flake.lock
index f04d657b0..34479856a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -42,15 +42,16 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1706629374,
-        "narHash": "sha256-KyAiLGxJ39fSY0cuq8EWAZQ4vaDdqAItSRP4+vjYvq8=",
-        "owner": "NixOS",
+        "lastModified": 1706306797,
+        "narHash": "sha256-nha3OTHgU/zSLNQhl4tZrkwehHZASd4KWOKZzp/uLew=",
+        "owner": "obsidiansystems",
         "repo": "nix",
-        "rev": "75ebb90a70f6320c1c7a1fca87a0a8adb0716143",
+        "rev": "e3ccb7e42a55529d8d50544e7e0cebb5cbc606cf",
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
+        "owner": "obsidiansystems",
+        "ref": "perl-open-other-store",
         "repo": "nix",
         "type": "github"
       }
diff --git a/flake.nix b/flake.nix
index 4dc7d25ea..b06a51e7d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,7 +2,7 @@
   description = "A Nix-based continuous build system";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05-small";
-  inputs.nix.url = "github:NixOS/nix";
+  inputs.nix.url = "github:obsidiansystems/nix/perl-open-other-store";
   inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
 
   # TODO get rid of this once https://github.com/NixOS/nix/pull/9546 is
diff --git a/src/lib/Hydra/Base/Controller/NixChannel.pm b/src/lib/Hydra/Base/Controller/NixChannel.pm
index 3f8e96096..a5bc2784e 100644
--- a/src/lib/Hydra/Base/Controller/NixChannel.pm
+++ b/src/lib/Hydra/Base/Controller/NixChannel.pm
@@ -4,7 +4,6 @@ use strict;
 use warnings;
 use base 'Hydra::Base::Controller::REST';
 use List::SomeUtils qw(any);
-use Nix::Store;
 use Hydra::Helper::Nix;
 use Hydra::Helper::CatalystUtils;
 
@@ -30,7 +29,7 @@ sub getChannelData {
         my $outputs = {};
         foreach my $output (@outputs) {
             my $outPath = $output->get_column("outpath");
-            next if $checkValidity && !isValidPath($outPath);
+            next if $checkValidity && !$MACHINE_LOCAL_STORE->isValidPath($outPath);
             $outputs->{$output->get_column("outname")} = $outPath;
             push @storePaths, $outPath;
             # Put the system type in the manifest (for top-level
diff --git a/src/lib/Hydra/Controller/Build.pm b/src/lib/Hydra/Controller/Build.pm
index c3869838d..4c2e5b127 100644
--- a/src/lib/Hydra/Controller/Build.pm
+++ b/src/lib/Hydra/Controller/Build.pm
@@ -10,8 +10,6 @@ use File::Basename;
 use File::LibMagic;
 use File::stat;
 use Data::Dump qw(dump);
-use Nix::Store;
-use Nix::Config;
 use List::SomeUtils qw(all);
 use Encode;
 use JSON::PP;
@@ -82,9 +80,9 @@ sub build_GET {
     # false because `$_->path` will be empty
     $c->stash->{available} =
         $c->stash->{isLocalStore}
-        ? all { $_->path && isValidPath($_->path) } $build->buildoutputs->all
+        ? all { $_->path && $MACHINE_LOCAL_STORE->isValidPath($_->path) } $build->buildoutputs->all
         : 1;
-    $c->stash->{drvAvailable} = isValidPath $build->drvpath;
+    $c->stash->{drvAvailable} = $MACHINE_LOCAL_STORE->isValidPath $build->drvpath;
 
     if ($build->finished && $build->iscachedbuild) {
         my $path = ($build->buildoutputs)[0]->path or undef;
@@ -308,7 +306,7 @@ sub output : Chained('buildChain') PathPart Args(1) {
     error($c, "This build is not finished yet.") unless $build->finished;
     my $output = $build->buildoutputs->find({name => $outputName});
     notFound($c, "This build has no output named ‘$outputName’") unless defined $output;
-    gone($c, "Output is no longer available.") unless isValidPath $output->path;
+    gone($c, "Output is no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($output->path);
 
     $c->response->header('Content-Disposition', "attachment; filename=\"build-${\$build->id}-${\$outputName}.nar.bz2\"");
     $c->stash->{current_view} = 'NixNAR';
@@ -425,7 +423,7 @@ sub getDependencyGraph {
             };
         $$done{$path} = $node;
         my @refs;
-        foreach my $ref (queryReferences($path)) {
+        foreach my $ref ($MACHINE_LOCAL_STORE->queryReferences($path)) {
             next if $ref eq $path;
             next unless $runtime || $ref =~ /\.drv$/;
             getDependencyGraph($self, $c, $runtime, $done, $ref);
@@ -433,7 +431,7 @@ sub getDependencyGraph {
         }
         # Show in reverse topological order to flatten the graph.
         # Should probably do a proper BFS.
-        my @sorted = reverse topoSortPaths(@refs);
+        my @sorted = reverse $MACHINE_LOCAL_STORE->topoSortPaths(@refs);
         $node->{refs} = [map { $$done{$_} } @sorted];
     }
 
@@ -446,7 +444,7 @@ sub build_deps : Chained('buildChain') PathPart('build-deps') {
     my $build = $c->stash->{build};
     my $drvPath = $build->drvpath;
 
-    error($c, "Derivation no longer available.") unless isValidPath $drvPath;
+    error($c, "Derivation no longer available.") unless $MACHINE_LOCAL_STORE->isValidPath($drvPath);
 
     $c->stash->{buildTimeGraph} = getDependencyGraph($self, $c, 0, {}, $drvPath);
 
@@ -461,7 +459,7 @@ sub runtime_deps : Chained('buildChain') PathPart('runtime-deps') {
 
     requireLocalStore($c);
 
-    error($c, "Build outputs no longer available.") unless all { isValidPath($_) } @outPaths;
+    error($c, "Build outputs no longer available.") unless all { $MACHINE_LOCAL_STORE->isValidPath($_) } @outPaths;
 
     my $done = {};
     $c->stash->{runtimeGraph} = [ map { getDependencyGraph($self, $c, 1, $done, $_) } @outPaths ];
@@ -481,7 +479,7 @@ sub nix : Chained('buildChain') PathPart('nix') CaptureArgs(0) {
     if (isLocalStore) {
         foreach my $out ($build->buildoutputs) {
             notFound($c, "Path " . $out->path . " is no longer available.")
-                unless isValidPath($out->path);
+                unless $MACHINE_LOCAL_STORE->isValidPath($out->path);
         }
     }
 
diff --git a/src/lib/Hydra/Controller/Root.pm b/src/lib/Hydra/Controller/Root.pm
index 548cfac34..162f347ef 100644
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -395,7 +395,7 @@ sub narinfo :Path :Args(StrMatch[NARINFO_REGEX]) {
         my ($hash) = $narinfo =~ NARINFO_REGEX;
 
         die("Hash length was not 32") if length($hash) != 32;
-        my $path = queryPathFromHashPart($hash);
+        my $path = $MACHINE_LOCAL_STORE->queryPathFromHashPart($hash);
 
         if (!$path) {
             $c->response->status(404);
diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index 71a8a7d77..3c3965dfa 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -40,8 +40,13 @@ our @EXPORT = qw(
     registerRoot
     restartBuilds
     run
+    $MACHINE_LOCAL_STORE
+    $BINARY_CACHE_STORE
     );
 
+our $MACHINE_LOCAL_STORE = Nix::Store->new();
+our $BINARY_CACHE_STORE = Nix::Store->new(getStoreUri());
+
 
 sub getHydraHome {
     my $dir = $ENV{"HYDRA_HOME"} or die "The HYDRA_HOME directory does not exist!\n";
@@ -494,7 +499,7 @@ sub restartBuilds {
     $builds = $builds->search({ finished => 1 });
 
     foreach my $build ($builds->search({}, { columns => ["drvpath"] })) {
-        next if !isValidPath($build->drvpath);
+        next if !$MACHINE_LOCAL_STORE->isValidPath($build->drvpath);
         registerRoot $build->drvpath;
     }
 
diff --git a/src/lib/Hydra/Plugin/BazaarInput.pm b/src/lib/Hydra/Plugin/BazaarInput.pm
index 230d108b8..b35ed7c8c 100644
--- a/src/lib/Hydra/Plugin/BazaarInput.pm
+++ b/src/lib/Hydra/Plugin/BazaarInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
-use Nix::Store;
 
 sub supportedInputTypes {
     my ($self, $inputTypes) = @_;
@@ -38,9 +37,9 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedBazaarInputs')->search(
         {uri => $uri, revision => $revision});
 
-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
     } else {
@@ -58,7 +57,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', $stdout;
 
         # FIXME: time window between nix-prefetch-bzr and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedBazaarInputs')->create(
diff --git a/src/lib/Hydra/Plugin/DarcsInput.pm b/src/lib/Hydra/Plugin/DarcsInput.pm
index b7f3db550..a8df63964 100644
--- a/src/lib/Hydra/Plugin/DarcsInput.pm
+++ b/src/lib/Hydra/Plugin/DarcsInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
-use Nix::Store;
 
 sub supportedInputTypes {
     my ($self, $inputTypes) = @_;
@@ -58,7 +57,7 @@ sub fetchInput {
         {uri => $uri, revision => $revision},
         {rows => 1});
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $revision = $cachedInput->revision;
@@ -75,8 +74,8 @@ sub fetchInput {
         die "darcs changes --count failed" if $? != 0;
 
         system "rm", "-rf", "$tmpDir/export/_darcs";
-        $storePath = addToStore("$tmpDir/export", 1, "sha256");
-        $sha256 = queryPathHash($storePath);
+        $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/export", 1, "sha256");
+        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath);
         $sha256 =~ s/sha256://;
 
         $self->{db}->txn_do(sub {
diff --git a/src/lib/Hydra/Plugin/GitInput.pm b/src/lib/Hydra/Plugin/GitInput.pm
index e5fc7de92..0de021282 100644
--- a/src/lib/Hydra/Plugin/GitInput.pm
+++ b/src/lib/Hydra/Plugin/GitInput.pm
@@ -186,9 +186,9 @@ sub fetchInput {
         {uri => $uri, branch => $branch, revision => $revision, isdeepclone => defined($deepClone) ? 1 : 0},
         {rows => 1});
 
-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $revision = $cachedInput->revision;
@@ -217,7 +217,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', grab(cmd => ["nix-prefetch-git", $clonePath, $revision], chomp => 1);
 
         # FIXME: time window between nix-prefetch-git and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedGitInputs')->update_or_create(
diff --git a/src/lib/Hydra/Plugin/MercurialInput.pm b/src/lib/Hydra/Plugin/MercurialInput.pm
index 921262ad7..85bd2c708 100644
--- a/src/lib/Hydra/Plugin/MercurialInput.pm
+++ b/src/lib/Hydra/Plugin/MercurialInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use File::Path;
 use Hydra::Helper::Nix;
 use Hydra::Helper::Exec;
-use Nix::Store;
 use Fcntl qw(:flock);
 
 sub supportedInputTypes {
@@ -68,9 +67,9 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedHgInputs')->search(
         {uri => $uri, branch => $branch, revision => $revision});
 
-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
     } else {
@@ -85,7 +84,7 @@ sub fetchInput {
         ($sha256, $storePath) = split ' ', $stdout;
 
         # FIXME: time window between nix-prefetch-hg and addTempRoot.
-        addTempRoot($storePath);
+        $MACHINE_LOCAL_STORE->addTempRoot($storePath);
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedHgInputs')->update_or_create(
diff --git a/src/lib/Hydra/Plugin/PathInput.pm b/src/lib/Hydra/Plugin/PathInput.pm
index d122ff573..c923a03c3 100644
--- a/src/lib/Hydra/Plugin/PathInput.pm
+++ b/src/lib/Hydra/Plugin/PathInput.pm
@@ -5,7 +5,6 @@ use warnings;
 use parent 'Hydra::Plugin';
 use POSIX qw(strftime);
 use Hydra::Helper::Nix;
-use Nix::Store;
 
 sub supportedInputTypes {
     my ($self, $inputTypes) = @_;
@@ -30,7 +29,7 @@ sub fetchInput {
         {srcpath => $uri, lastseen => {">", $timestamp - $timeout}},
         {rows => 1, order_by => "lastseen DESC"});
 
-    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
+    if (defined $cachedInput && $MACHINE_LOCAL_STORE->isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
         $sha256 = $cachedInput->sha256hash;
         $timestamp = $cachedInput->timestamp;
@@ -46,7 +45,7 @@ sub fetchInput {
         }
         chomp $storePath;
 
-        $sha256 = (queryPathInfo($storePath, 0))[1] or die;
+        $sha256 = ($MACHINE_LOCAL_STORE->queryPathInfo($storePath, 0))[1] or die;
 
         ($cachedInput) = $self->{db}->resultset('CachedPathInputs')->search(
             {srcpath => $uri, sha256hash => $sha256});
diff --git a/src/lib/Hydra/Plugin/SubversionInput.pm b/src/lib/Hydra/Plugin/SubversionInput.pm
index 456c6892a..83c1f39d2 100644
--- a/src/lib/Hydra/Plugin/SubversionInput.pm
+++ b/src/lib/Hydra/Plugin/SubversionInput.pm
@@ -7,7 +7,6 @@ use Digest::SHA qw(sha256_hex);
 use Hydra::Helper::Exec;
 use Hydra::Helper::Nix;
 use IPC::Run;
-use Nix::Store;
 
 sub supportedInputTypes {
     my ($self, $inputTypes) = @_;
@@ -45,7 +44,7 @@ sub fetchInput {
     (my $cachedInput) = $self->{db}->resultset('CachedSubversionInputs')->search(
         {uri => $uri, revision => $revision});
 
-    addTempRoot($cachedInput->storepath) if defined $cachedInput;
+    $MACHINE_LOCAL_STORE->addTempRoot($cachedInput->storepath) if defined $cachedInput;
 
     if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
         $storePath = $cachedInput->storepath;
@@ -62,16 +61,16 @@ sub fetchInput {
         die "error checking out Subversion repo at `$uri':\n$stderr" if $res;
 
         if ($type eq "svn-checkout") {
-            $storePath = addToStore($wcPath, 1, "sha256");
+            $storePath = $MACHINE_LOCAL_STORE->addToStore($wcPath, 1, "sha256");
         } else {
             # Hm, if the Nix Perl bindings supported filters in
             # addToStore(), then we wouldn't need to make a copy here.
             my $tmpDir = File::Temp->newdir("hydra-svn-export.XXXXXX", CLEANUP => 1, TMPDIR => 1) or die;
             (system "svn", "export", $wcPath, "$tmpDir/source", "--quiet") == 0 or die "svn export failed";
-            $storePath = addToStore("$tmpDir/source", 1, "sha256");
+            $storePath = $MACHINE_LOCAL_STORE->addToStore("$tmpDir/source", 1, "sha256");
         }
 
-        $sha256 = queryPathHash($storePath); $sha256 =~ s/sha256://;
+        $sha256 = $MACHINE_LOCAL_STORE->queryPathHash($storePath); $sha256 =~ s/sha256://;
 
         $self->{db}->txn_do(sub {
             $self->{db}->resultset('CachedSubversionInputs')->update_or_create(
diff --git a/src/lib/Hydra/View/NARInfo.pm b/src/lib/Hydra/View/NARInfo.pm
index 44db78b14..bf8711a4a 100644
--- a/src/lib/Hydra/View/NARInfo.pm
+++ b/src/lib/Hydra/View/NARInfo.pm
@@ -6,8 +6,7 @@ use File::Basename;
 use Hydra::Helper::CatalystUtils;
 use MIME::Base64;
 use Nix::Manifest;
-use Nix::Store;
-use Nix::Utils;
+use Hydra::Helper::Nix;
 use base qw/Catalyst::View/;
 
 sub process {
@@ -17,7 +16,7 @@ sub process {
 
     $c->response->content_type('text/x-nix-narinfo'); # !!! check MIME type
 
-    my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($storePath, 1);
+    my ($deriver, $narHash, $time, $narSize, $refs) = $MACHINE_LOCAL_STORE->queryPathInfo($storePath, 1);
 
     my $info;
     $info .= "StorePath: $storePath\n";
@@ -28,8 +27,8 @@ sub process {
     $info .= "References: " . join(" ", map { basename $_ } @{$refs}) . "\n";
     if (defined $deriver) {
         $info .= "Deriver: " . basename $deriver . "\n";
-        if (isValidPath($deriver)) {
-            my $drv = derivationFromPath($deriver);
+        if ($MACHINE_LOCAL_STORE->isValidPath($deriver)) {
+            my $drv = $MACHINE_LOCAL_STORE->derivationFromPath($deriver);
             $info .= "System: $drv->{platform}\n";
         }
     }
diff --git a/src/script/hydra-eval-jobset b/src/script/hydra-eval-jobset
index 7ed7ebe83..72a386f57 100755
--- a/src/script/hydra-eval-jobset
+++ b/src/script/hydra-eval-jobset
@@ -85,14 +85,14 @@ sub attrsToSQL {
 # Fetch a store path from 'eval_substituter' if not already present.
 sub getPath {
     my ($path) = @_;
-    return 1 if isValidPath($path);
+    return 1 if $MACHINE_LOCAL_STORE->isValidPath($path);
 
     my $substituter = $config->{eval_substituter};
 
     system("nix", "--experimental-features", "nix-command", "copy", "--from", $substituter, "--", $path)
         if defined $substituter;
 
-    return isValidPath($path);
+    return $MACHINE_LOCAL_STORE->isValidPath($path);
 }
 
 
@@ -143,7 +143,7 @@ sub fetchInputBuild {
         , version => $version
         , outputName => $mainOutput->name
         };
-    if (isValidPath($prevBuild->drvpath)) {
+    if ($MACHINE_LOCAL_STORE->isValidPath($prevBuild->drvpath)) {
         $result->{drvPath} = $prevBuild->drvpath;
     }
 
@@ -233,7 +233,7 @@ sub fetchInputEval {
         my $out = $build->buildoutputs->find({ name => "out" });
         next unless defined $out;
         # FIXME: Should we fail if the path is not valid?
-        next unless isValidPath($out->path);
+        next unless $MACHINE_LOCAL_STORE->isValidPath($out->path);
         $jobs->{$build->get_column('job')} = $out->path;
     }
 
diff --git a/src/script/hydra-update-gc-roots b/src/script/hydra-update-gc-roots
index 11eba7a6a..130cbb682 100755
--- a/src/script/hydra-update-gc-roots
+++ b/src/script/hydra-update-gc-roots
@@ -5,7 +5,6 @@ use warnings;
 use File::Path;
 use File::stat;
 use File::Basename;
-use Nix::Store;
 use Hydra::Config;
 use Hydra::Schema;
 use Hydra::Helper::Nix;
@@ -47,7 +46,7 @@ sub keepBuild {
         $build->finished && ($build->buildstatus == 0 || $build->buildstatus == 6))
     {
         foreach my $path (split / /, $build->get_column('outpaths')) {
-            if (isValidPath($path)) {
+            if ($MACHINE_LOCAL_STORE->isValidPath($path)) {
                 addRoot $path;
             } else {
                 print STDERR "    warning: output ", $path, " has disappeared\n" if $build->finished;
@@ -55,7 +54,7 @@ sub keepBuild {
         }
     }
     if (!$build->finished || ($keepFailedDrvs && $build->buildstatus != 0)) {
-        if (isValidPath($build->drvpath)) {
+        if ($MACHINE_LOCAL_STORE->isValidPath($build->drvpath)) {
             addRoot $build->drvpath;
         } else {
             print STDERR "    warning: derivation ", $build->drvpath, " has disappeared\n";
diff --git a/t/s3-backup-test.pl b/t/s3-backup-test.pl
index 9332ab15b..a367981fe 100644
--- a/t/s3-backup-test.pl
+++ b/t/s3-backup-test.pl
@@ -3,7 +3,6 @@
 use File::Basename;
 use Hydra::Model::DB;
 use Hydra::Helper::Nix;
-use Nix::Store;
 use Cwd;
 
 my $db = Hydra::Model::DB->new;