diff --git a/lib/SyTest/Homeserver/Dendrite.pm b/lib/SyTest/Homeserver/Dendrite.pm
index 9c02c2eec..75d2d472a 100644
--- a/lib/SyTest/Homeserver/Dendrite.pm
+++ b/lib/SyTest/Homeserver/Dendrite.pm
@@ -63,7 +63,8 @@ sub _check_db_config
    my $self = shift;
    my ( %config ) = @_;
 
-   $config{type} eq "pg" or die "Dendrite can only run against postgres";
+   # We're in the business of running sytest against dendrite+sqlite these days
+   #$config{type} eq "pg" or die "Dendrite can only run against postgres";
 
    return $self->SUPER::_check_db_config( @_ );
 }
diff --git a/lib/SyTest/Homeserver/ProcessManager.pm b/lib/SyTest/Homeserver/ProcessManager.pm
index 00e953439..4aa3c9b0f 100644
--- a/lib/SyTest/Homeserver/ProcessManager.pm
+++ b/lib/SyTest/Homeserver/ProcessManager.pm
@@ -316,7 +316,7 @@ sub _await_ready_notification
    # We replace null byte with '@' to allow us to pass it in via env. (This is
    # as per the sd_notify spec).
    my $path_env = $path;
-   $path_env =~ s/\0/\@/rg;
+   $path_env =~ s/\0/\@/g;
    $env->{"NOTIFY_SOCKET"} = $path_env;
 
    # Create a future that gets resolved when we receive a `READY=1`
diff --git a/tests/10apidoc/30room-create.pl b/tests/10apidoc/30room-create.pl
index 91c726588..cc7f52f7f 100644
--- a/tests/10apidoc/30room-create.pl
+++ b/tests/10apidoc/30room-create.pl
@@ -16,7 +16,7 @@
          content => {
             visibility      => "public",
             # This is just the localpart
-            room_alias_name => "30room-create",
+            room_alias_name => "30room-create-".time,
          },
       )->then( sub {
          my ( $body ) = @_;
diff --git a/tests/31sync/17peeking.pl b/tests/31sync/17peeking.pl
new file mode 100644
index 000000000..2e23ead0e
--- /dev/null
+++ b/tests/31sync/17peeking.pl
@@ -0,0 +1,222 @@
+use Future::Utils qw( repeat );
+use JSON qw( decode_json );
+
+# Tests MSC2753 style peeking
+
+test "Local users can peek into world_readable rooms by room ID",
+   requires => [ local_user_and_room_fixtures(), local_user_fixture() ],
+
+   check => sub {
+      my ( $user, $room_id, $peeking_user ) = @_;
+
+      matrix_set_room_history_visibility( $user, $room_id, "world_readable" )->then(sub {
+         do_request_json_for( $peeking_user,
+            method => "POST",
+            uri    => "/r0/peek/$room_id",
+            content => {},
+         )
+      })->then( sub {
+         matrix_send_room_text_message_synced( $user, $room_id, body => "something to peek");
+      })->then(sub {
+         await_sync( $peeking_user,
+            since => $peeking_user->sync_next_batch,
+            check => sub {
+               my ( $body ) = @_;
+               return 0 unless $body->{rooms}{peek}{$room_id};
+               return $body;
+            }
+         )
+      })->then( sub {
+         my ( $body ) = @_;
+         $peeking_user->sync_next_batch = $body->{next_batch};
+
+         log_if_fail "first sync response", $body;
+
+         my $room = $body->{rooms}{peek}{$room_id};
+         assert_json_keys( $room, qw( timeline state ephemeral ));
+         assert_json_keys( $room->{timeline}, qw( events limited prev_batch ));
+         assert_json_keys( $room->{state}, qw( events ));
+         assert_json_keys( $room->{ephemeral}, qw( events ));
+
+         assert_ok( $room->{timeline}->{events}->[0]->{type} eq 'm.room.create', "peek has m.room.create" );
+         assert_ok( $room->{timeline}->{events}->[-1]->{type} eq 'm.room.message', "peek has message type" );
+         assert_ok( $room->{timeline}->{events}->[-1]->{content}->{body} eq 'something to peek', "peek has message body" );
+         assert_ok( @{$room->{state}->{events}} == 0 );
+
+         assert_ok( scalar keys(%{$body->{rooms}{join}}) == 0, "no joined rooms present");
+
+         matrix_sync_again( $peeking_user );
+      })->then( sub {
+         my ( $body ) = @_;
+
+         log_if_fail "second sync response", $body;
+         my $room = $body->{rooms}{peek}{$room_id};
+         (!defined $room) or die "Unchanged rooms shouldn't be in the sync response";
+      })->then( sub {
+         matrix_send_room_text_message_synced( $user, $room_id, body => "something else to peek");
+      })->then( sub {
+         await_sync( $peeking_user,
+            since => $peeking_user->sync_next_batch,
+            check => sub {
+               my ( $body ) = @_;
+               return 0 unless $body->{rooms}{peek}{$room_id};
+               return $body;
+            }
+         )
+      })->then( sub {
+         my ( $body ) = @_;
+         $peeking_user->sync_next_batch = $body->{next_batch};
+
+         log_if_fail "third sync response", $body;
+         my $room = $body->{rooms}{peek}{$room_id};
+
+         assert_ok( $room->{timeline}->{events}->[-1]->{type} eq 'm.room.message', "second peek has message type" );
+         assert_ok( $room->{timeline}->{events}->[-1]->{content}->{body} eq 'something else to peek', "second peek has message body" );
+
+         Future->done(1)
+      })
+   };
+
+
+for my $visibility (qw(shared invited joined)) {
+   test "We can't peek into rooms with $visibility history_visibility",
+      requires => [ local_user_and_room_fixtures(), local_user_fixture() ],
+
+      check => sub {
+         my ( $user, $room_id, $peeking_user ) = @_;
+
+         matrix_set_room_history_visibility( $user, $room_id, $visibility )->then(sub {
+            do_request_json_for( $peeking_user,
+               method => "POST",
+               uri    => "/r0/peek/$room_id",
+               content => {},
+            );
+         })->main::expect_http_403()
+         ->then( sub {
+            my ( $response ) = @_;
+            my $body = decode_json( $response->content );
+            log_if_fail "error body", $body;
+            assert_eq( $body->{errcode}, "M_FORBIDDEN", 'responsecode' );
+            Future->done( 1 );
+         });
+      };
+}
+
+
+my $room_alias_name = sprintf("peektest-%s", $TEST_RUN_ID);
+test "Local users can peek by room alias",
+   requires => [
+      local_user_and_room_fixtures(room_opts => { room_alias_name => $room_alias_name }),
+      local_user_fixture()
+   ],
+
+   check => sub {
+      my ( $user, $room_id, $peeking_user ) = @_;
+
+      matrix_set_room_history_visibility( $user, $room_id, "world_readable" )->then(sub {
+         do_request_json_for( $peeking_user,
+            method => "POST",
+            uri    => "/r0/peek/#$room_alias_name:".$user->http->server_name,
+            content => {},
+         )
+      })->then(sub {
+         matrix_send_room_text_message_synced( $user, $room_id, body => "something to peek");
+      })->then(sub {
+         await_sync( $peeking_user,
+            since => $peeking_user->sync_next_batch,
+            check => sub {
+               my ( $body ) = @_;
+               return 0 unless $body->{rooms}{peek}{$room_id};
+               return $body;
+            }
+         )
+      })->then( sub {
+         my ( $body ) = @_;
+         $peeking_user->sync_next_batch = $body->{next_batch};
+
+         log_if_fail "first sync response", $body;
+
+         my $room = $body->{rooms}{peek}{$room_id};
+         assert_ok( $room->{timeline}->{events}->[-1]->{content}->{body} eq 'something to peek', "peek has message body" );
+         Future->done(1)
+      })
+   };
+
+test "Peeked rooms only turn up in the sync for the device who peeked them",
+   requires => [ local_user_and_room_fixtures(), local_user_fixture() ],
+
+   check => sub {
+      my ( $user, $room_id, $peeking_user ) = @_;
+      my ( $peeking_user_device2 );
+
+      matrix_set_room_history_visibility( $user, $room_id, "world_readable" )->then(sub {
+         matrix_login_again_with_user($peeking_user);
+      })->then(sub {
+         $peeking_user_device2 = $_[0];
+         do_request_json_for( $peeking_user,
+            method => "POST",
+            uri    => "/r0/peek/$room_id",
+            content => {},
+         )
+      })->then(sub {
+         matrix_send_room_text_message_synced( $user, $room_id, body => "something to peek");
+      })->then(sub {
+         await_sync( $peeking_user,
+            since => $peeking_user->sync_next_batch,
+            check => sub {
+               my ( $body ) = @_;
+               return 0 unless $body->{rooms}{peek}{$room_id};
+               return $body;
+            }
+         )
+      })->then( sub {
+         my ( $body ) = @_;
+         $peeking_user->sync_next_batch = $body->{next_batch};
+         log_if_fail "device 1 first sync response", $body;
+         my $room = $body->{rooms}{peek}{$room_id};
+         assert_ok( $room->{timeline}->{events}->[-1]->{content}->{body} eq 'something to peek', "peek has message body" );
+      })->then(sub {
+         # FIXME: racey - this may return blank due to the peek not having taken effect yet
+         matrix_sync( $peeking_user_device2, timeout => 1000 );
+      })->then( sub {
+         my ( $body ) = @_;
+         log_if_fail "device 2 first sync response", $body;
+         assert_ok( scalar keys(%{$body->{rooms}{peek}}) == 0, "no peeked rooms present");
+      })->then( sub {
+         matrix_send_room_text_message_synced( $user, $room_id, body => "something else to peek")
+      })->then( sub {
+         await_sync( $peeking_user,
+            since => $peeking_user->sync_next_batch,
+            check => sub {
+               my ( $body ) = @_;
+               return 0 unless $body->{rooms}{peek}{$room_id};
+               return $body;
+            }
+         )
+      })->then( sub {
+         my ( $body ) = @_;
+         $peeking_user->sync_next_batch = $body->{next_batch};
+         log_if_fail "device 1 second sync response", $body;
+         my $room = $body->{rooms}{peek}{$room_id};
+         assert_ok( $room->{timeline}->{events}->[-1]->{content}->{body} eq 'something else to peek', "second peek has message body" );
+         # FIXME: racey - this may return blank due to the peek not having taken effect yet
+         matrix_sync_again( $peeking_user_device2, timeout => 1000 );
+      })->then( sub {
+         my ( $body ) = @_;
+         log_if_fail "device 2 second sync response", $body;
+         assert_ok( scalar keys(%{$body->{rooms}{peek}}) == 0, "still no peeked rooms present");
+         Future->done(1)
+      })
+   };
+
+# test "Users can unpeek from rooms"
+
+# test "Users can peek, unpeek and peek again"
+
+# test "Peeking with full_state=true does the right thing"
+
+# test "Joining a peeked room moves it atomically from peeked to joined rooms and stops peeking"
+
+# test "Parting a room which was joined after being peeked doesn't go back to being peeked"
+
+# test "Changing history visibility to non-world_readable terminates peeks"