diff --git a/cmd/backfill/main.go b/cmd/backfill/main.go
index 22ba5d575..655c36cac 100644
--- a/cmd/backfill/main.go
+++ b/cmd/backfill/main.go
@@ -8,7 +8,6 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"log"
 	"math/rand"
 	"os"
 	"regexp"
@@ -16,6 +15,8 @@ import (
 	"time"
 
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
 	"github.com/tidwall/gjson"
 )
 
@@ -27,6 +28,11 @@ var roomID = flag.String("room", "", "the room ID to backfill")
 
 // nolint: gocyclo
 func main() {
+	zerolog.TimeFieldFormat = time.RFC3339Nano
+	log.Logger = log.Output(zerolog.ConsoleWriter{
+		Out:        os.Stderr,
+		TimeFormat: "15:04:05.000",
+	})
 	flag.Parse()
 
 	if requestFrom == nil || *requestFrom == "" {
@@ -54,7 +60,9 @@ func main() {
 
 	data, err := os.ReadFile(*requestKey)
 	if err != nil {
-		panic(err)
+		log.Fatal().
+			Err(err).
+			Msg("failed to read file")
 	}
 
 	var privateKey ed25519.PrivateKey
@@ -88,28 +96,38 @@ func main() {
 		servers: map[gomatrixserverlib.ServerName]struct{}{
 			gomatrixserverlib.ServerName(*requestTo): {},
 		},
+		preferServer: gomatrixserverlib.ServerName(*requestTo),
 	}
 
 	ctx := context.Background()
 	eventID := *startEventID
 	start := time.Now()
+	seenEvents := make(map[string]struct{})
+
 	defer func() {
-		log.Printf("Backfilling took: %s", time.Since(start))
+		log.Debug().
+			TimeDiff("duration", time.Now(), start).
+			Int("events", len(seenEvents)).
+			Msg("Finished backfilling")
 	}()
-	f, err := os.Create(tokenise(*roomID) + "_backfill.csv")
+	f, err := os.Create(tokenise(*roomID) + "_backfill.json")
 	if err != nil {
-		log.Fatal(err)
+		log.Fatal().
+			Err(err).
+			Msg("failed to create JSON file")
 	}
 	defer f.Close() // nolint: errcheck
-	seenEvents := make(map[string]struct{})
 
 	encoder := json.NewEncoder(f)
 
 	for {
-		log.Printf("[%d] going to request %s\n", len(seenEvents), eventID)
+		log.Debug().
+			Int("events", len(seenEvents)).
+			Str("event_id", eventID).
+			Msg("requesting event")
 		evs, err := gomatrixserverlib.RequestBackfill(ctx, serverName, b, &nopJSONVerifier{}, *roomID, "9", []string{eventID}, 100)
 		if err != nil && len(evs) == 0 {
-			log.Printf("failed to backfill, retrying: %s", err)
+			log.Err(err).Msg("failed to backfill, retrying")
 			continue
 		}
 		var createSeen bool
@@ -131,15 +149,19 @@ func main() {
 			// The following ensures we preserve the "_event_id" field
 			err = encoder.Encode(x)
 			if err != nil {
-				log.Fatal(err)
+				log.Fatal().
+					Err(err).
+					Msg("failed to write to file")
 			}
 			if x.Type() == gomatrixserverlib.MRoomCreate {
 				createSeen = true
 			}
 		}
-		// We've reached the beginng of the room
+		// We've reached the beginning of the room
 		if createSeen {
-			log.Printf("[%d] Reached beginning of the room, exiting", len(seenEvents))
+			log.Debug().
+				Int("events", len(seenEvents)).
+				Msg("Reached beginning of the room, existing")
 			return
 		}
 
@@ -156,7 +178,8 @@ func main() {
 			break
 		}
 		if beforeEvID == eventID {
-			log.Printf("no new eventID found in backfill response")
+			log.Debug().
+				Msg("no new eventID found in backfill response")
 			return
 		}
 		// Finally store which events we've already seen
@@ -182,8 +205,9 @@ func (h headeredEvents) Swap(i, j int) {
 }
 
 type backfiller struct {
-	FedClient *gomatrixserverlib.FederationClient
-	servers   map[gomatrixserverlib.ServerName]struct{}
+	FedClient    *gomatrixserverlib.FederationClient
+	servers      map[gomatrixserverlib.ServerName]struct{}
+	preferServer gomatrixserverlib.ServerName
 }
 
 func (b backfiller) StateIDsBeforeEvent(ctx context.Context, event *gomatrixserverlib.HeaderedEvent) ([]string, error) {
@@ -201,7 +225,7 @@ func (b backfiller) Backfill(ctx context.Context, origin, server gomatrixserverl
 func (b backfiller) ServersAtEvent(ctx context.Context, roomID, eventID string) []gomatrixserverlib.ServerName {
 	servers := make([]gomatrixserverlib.ServerName, 0, len(b.servers)+1)
 	for v := range b.servers {
-		if v == "matrix.org" { // will be added to the front anyway
+		if v == b.preferServer { // will be added to the front anyway
 			continue
 		}
 		servers = append(servers, v)
@@ -210,8 +234,8 @@ func (b backfiller) ServersAtEvent(ctx context.Context, roomID, eventID string)
 		servers[i], servers[j] = servers[j], servers[i]
 	})
 
-	// always prefer matrix.org
-	servers = append([]gomatrixserverlib.ServerName{"matrix.org"}, servers...)
+	// always prefer specified server
+	servers = append([]gomatrixserverlib.ServerName{b.preferServer}, servers...)
 
 	if len(servers) > 5 {
 		servers = servers[:5]
diff --git a/go.mod b/go.mod
index 129576c64..59b9f2df3 100644
--- a/go.mod
+++ b/go.mod
@@ -94,6 +94,7 @@ require (
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
 	github.com/klauspost/compress v1.15.11 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.16 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 // indirect
 	github.com/minio/highwayhash v1.0.2 // indirect
@@ -118,6 +119,7 @@ require (
 	github.com/quic-go/qtls-go1-20 v0.1.0 // indirect
 	github.com/quic-go/quic-go v0.32.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20220927061507-ef77025ab5aa // indirect
+	github.com/rs/zerolog v1.29.0 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.1 // indirect
 	go.etcd.io/bbolt v1.3.6 // indirect
diff --git a/go.sum b/go.sum
index 591442f2a..f1dbf0e64 100644
--- a/go.sum
+++ b/go.sum
@@ -123,6 +123,7 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/codeclysm/extract v2.2.0+incompatible h1:q3wyckoA30bhUSiwdQezMqVhwd8+WGE64/GL//LtUhI=
 github.com/codeclysm/extract v2.2.0+incompatible/go.mod h1:2nhFMPHiU9At61hz+12bfrlpXSUrOnK+wR+KlGO4Uks=
+github.com/coreos/go-systemd/v22 v22.3.3-0.20220203105225-a9a7ef127534/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/creack/pty v1.1.11/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -188,6 +189,7 @@ github.com/gobwas/pool v0.2.0/go.mod h1:q8bcK0KcYlCgd9e7WYLm9LpyS+YeLd8JVDW6Wezm
 github.com/gobwas/ws v1.0.2 h1:CoAavW/wd/kulfZmSIBt6p24n4j7tHgNVCjsfHVNUbo=
 github.com/gobwas/ws v1.0.2/go.mod h1:szmBTxLgaFppYjEmNtny/v3w89xOydFnnZMcgRRu/EM=
 github.com/goccy/go-json v0.9.11 h1:/pAaQDLHEoCq/5FFmSKBswWmK6H0e8g4159Kc/X/nqk=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -331,7 +333,11 @@ github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a h1:awrPDf9L
 github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a/go.mod h1:HchJX9oKMXaT2xYFs0Ha/6Zs06mxLU8k6F1ODnrGkeQ=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66 h1:6z4KxomXSIGWqhHcfzExgkH3Z3UkIXry4ibJS4Aqz2Y=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66/go.mod h1:iBI1foelCqA09JJgPV0FYz4qA5dUXYOxMi57FxKBdd4=
+github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
 github.com/mattn/go-isatty v0.0.16 h1:bq3VjFmv/sOjHtdEhmkEV4x1AJtvUvOJ2PFAZ5+peKQ=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
 github.com/mattn/go-sqlite3 v1.14.15 h1:vfoHhTN1af61xCRSWzFIWzx2YskyMTwHLrExkBOjvxI=
@@ -436,6 +442,9 @@ github.com/remyoudompheng/bigfft v0.0.0-20220927061507-ef77025ab5aa/go.mod h1:qq
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/rs/xid v1.4.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+github.com/rs/zerolog v1.29.0 h1:Zes4hju04hjbvkVkOhdl2HpZa+0PmVwigmo8XoORE5w=
+github.com/rs/zerolog v1.29.0/go.mod h1:NILgTygv/Uej1ra5XxGf82ZFSLk58MFGAUS2o6usyD0=
 github.com/ryszard/goskiplist v0.0.0-20150312221310-2dfbae5fcf46/go.mod h1:uAQ5PCi+MFsC7HjREoAz1BU+Mq60+05gifQSsHSDG/8=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
@@ -655,6 +664,8 @@ golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=