diff --git a/go.mod b/go.mod
index f05a0b101..3f7e44358 100644
--- a/go.mod
+++ b/go.mod
@@ -58,6 +58,7 @@ require (
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/koron/go-ssdp v0.0.3
 	github.com/korylprince/ipnetgen v1.0.1
+	github.com/kr/pretty v0.3.0
 	github.com/libp2p/zeroconf/v2 v2.2.0
 	github.com/lorenzodonini/ocpp-go v0.16.1-0.20230224180512-0195c3faf41a
 	github.com/lunixbochs/struc v0.0.0-20200707160740-784aaebc1d40
@@ -144,6 +145,7 @@ require (
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/compress v1.15.15 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/leodido/go-urn v1.2.1 // indirect
 	github.com/magiconair/properties v1.8.7 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
diff --git a/server/socket.go b/server/socket.go
index 41ae4b4ca..9aaaf8cee 100644
--- a/server/socket.go
+++ b/server/socket.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/evcc-io/evcc/util"
 	"github.com/gorilla/websocket"
+	"github.com/kr/pretty"
 )
 
 const (
@@ -121,7 +122,7 @@ func kv(p util.Param) string {
 	}
 
 	if p.Key == "" && val == "" {
-		log.ERROR.Printf("invalid key/val for %+v %+v, please report to https://github.com/evcc-io/evcc/issues/6439", p, p.Val)
+		log.ERROR.Printf("invalid key/val for %+v %# v, please report to https://github.com/evcc-io/evcc/issues/6439", p, pretty.Formatter(p.Val))
 		return "\"foo\":\"bar\""
 	}