diff --git a/internal/notifier/discord.go b/internal/notifier/discord.go
index 932d07ec9..0651d5d56 100644
--- a/internal/notifier/discord.go
+++ b/internal/notifier/discord.go
@@ -19,8 +19,10 @@ package notifier
 import (
 	"context"
 	"fmt"
+	"maps"
 	"net/url"
 	"path"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -71,7 +73,8 @@ func (s *Discord) Post(ctx context.Context, event eventv1.Event) error {
 	}
 
 	sfields := make([]SlackField, 0, len(event.Metadata))
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		sfields = append(sfields, SlackField{k, v, false})
 	}
 
diff --git a/internal/notifier/google_chat.go b/internal/notifier/google_chat.go
index 74b33f5b4..69c2783ed 100644
--- a/internal/notifier/google_chat.go
+++ b/internal/notifier/google_chat.go
@@ -19,7 +19,9 @@ package notifier
 import (
 	"context"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -114,7 +116,8 @@ func (s *GoogleChat) Post(ctx context.Context, event eventv1.Event) error {
 	// Meta-Data
 	if len(event.Metadata) > 0 {
 		kvfields := make([]GoogleChatCardWidget, 0, len(event.Metadata))
-		for k, v := range event.Metadata {
+		for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+			v := event.Metadata[k]
 			kvfields = append(kvfields, GoogleChatCardWidget{
 				KeyValue: &GoogleChatCardWidgetKeyValue{
 					TopLabel:         k,
diff --git a/internal/notifier/grafana.go b/internal/notifier/grafana.go
index 279fa4876..d5080b20a 100644
--- a/internal/notifier/grafana.go
+++ b/internal/notifier/grafana.go
@@ -20,7 +20,9 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -65,7 +67,8 @@ func (g *Grafana) Post(ctx context.Context, event eventv1.Event) error {
 	sfields := make([]string, 0, len(event.Metadata))
 	// add tag to filter on grafana
 	sfields = append(sfields, "flux", event.ReportingController)
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		key := strings.ReplaceAll(k, ":", "|")
 		value := strings.ReplaceAll(v, ":", "|")
 		sfields = append(sfields, fmt.Sprintf("%s: %s", key, value))
diff --git a/internal/notifier/lark.go b/internal/notifier/lark.go
index 0ba723051..4a499929b 100644
--- a/internal/notifier/lark.go
+++ b/internal/notifier/lark.go
@@ -3,7 +3,9 @@ package notifier
 import (
 	"context"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -70,7 +72,8 @@ func (l *Lark) Post(ctx context.Context, event eventv1.Event) error {
 	}
 
 	message := fmt.Sprintf("**%s**\n\n", event.Message)
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		message = message + fmt.Sprintf("%s: %s\n", k, v)
 	}
 
diff --git a/internal/notifier/matrix.go b/internal/notifier/matrix.go
index 07eabc098..b1ae5d298 100644
--- a/internal/notifier/matrix.go
+++ b/internal/notifier/matrix.go
@@ -6,8 +6,10 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"maps"
 	"net/http"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -53,7 +55,8 @@ func (m *Matrix) Post(ctx context.Context, event eventv1.Event) error {
 		emoji = "🚨"
 	}
 	var metadata string
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		metadata = metadata + fmt.Sprintf("- %s: %s\n", k, v)
 	}
 	heading := fmt.Sprintf("%s %s/%s.%s", emoji, strings.ToLower(event.InvolvedObject.Kind),
diff --git a/internal/notifier/rocket.go b/internal/notifier/rocket.go
index 08d46944e..b8609b55b 100644
--- a/internal/notifier/rocket.go
+++ b/internal/notifier/rocket.go
@@ -20,7 +20,9 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -64,7 +66,8 @@ func (s *Rocket) Post(ctx context.Context, event eventv1.Event) error {
 	}
 
 	sfields := make([]SlackField, 0, len(event.Metadata))
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		sfields = append(sfields, SlackField{k, v, false})
 	}
 
diff --git a/internal/notifier/slack.go b/internal/notifier/slack.go
index b235f16bb..fc3c42456 100644
--- a/internal/notifier/slack.go
+++ b/internal/notifier/slack.go
@@ -21,8 +21,10 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"maps"
 	"net/http"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -102,7 +104,8 @@ func (s *Slack) Post(ctx context.Context, event eventv1.Event) error {
 	}
 
 	sfields := make([]SlackField, 0, len(event.Metadata))
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		sfields = append(sfields, SlackField{k, v, false})
 	}
 
diff --git a/internal/notifier/slack_test.go b/internal/notifier/slack_test.go
index f73abe66d..64e9d655a 100644
--- a/internal/notifier/slack_test.go
+++ b/internal/notifier/slack_test.go
@@ -66,3 +66,46 @@ func TestSlack_ValidateResponse(t *testing.T) {
 	err = validateSlackResponse(resp.Result())
 	g.Expect(err).To(MatchError(ContainSubstring("Slack responded with error: too_many_attachments")))
 }
+
+// Go randomises map iteration, so the fields shuffled between messages and the
+// same four keys arrived in a different order every time. Ten posts of one event
+// is enough for an unsorted map to disagree with itself.
+func TestSlack_PostFieldsAreSorted(t *testing.T) {
+	g := NewWithT(t)
+
+	var got [][]string
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		b, err := io.ReadAll(r.Body)
+		g.Expect(err).ToNot(HaveOccurred())
+
+		var payload SlackPayload
+		g.Expect(json.Unmarshal(b, &payload)).To(Succeed())
+
+		keys := make([]string, 0, len(payload.Attachments[0].Fields))
+		for _, f := range payload.Attachments[0].Fields {
+			keys = append(keys, f.Title)
+		}
+		got = append(got, keys)
+	}))
+	defer ts.Close()
+
+	slack, err := NewSlack(ts.URL, "", "", nil, "", "test")
+	g.Expect(err).ToNot(HaveOccurred())
+
+	event := testEvent()
+	event.Metadata = map[string]string{
+		"revision":  "main/1234",
+		"cluster":   "staging",
+		"image-tag": "v1.2.3",
+		"env":       "staging",
+	}
+
+	for i := 0; i < 10; i++ {
+		g.Expect(slack.Post(context.TODO(), event)).To(Succeed())
+	}
+
+	want := []string{"cluster", "env", "image-tag", "revision"}
+	for i, keys := range got {
+		g.Expect(keys).To(Equal(want), "post %d returned fields out of order", i)
+	}
+}
diff --git a/internal/notifier/teams.go b/internal/notifier/teams.go
index 43ad99495..8af55db8f 100644
--- a/internal/notifier/teams.go
+++ b/internal/notifier/teams.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"maps"
 	"net/url"
 	"slices"
 	"strings"
@@ -173,7 +174,8 @@ func (s *MSTeams) Post(ctx context.Context, event eventv1.Event) error {
 
 func buildMSTeamsDeprecatedConnectorPayload(event *eventv1.Event, objName string) *MSTeamsPayload {
 	facts := make([]MSTeamsField, 0, len(event.Metadata))
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		facts = append(facts, MSTeamsField{
 			Name:  k,
 			Value: v,
diff --git a/internal/notifier/telegram.go b/internal/notifier/telegram.go
index cad10e270..76be5e74c 100644
--- a/internal/notifier/telegram.go
+++ b/internal/notifier/telegram.go
@@ -4,7 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -57,7 +59,8 @@ func (t *Telegram) Post(ctx context.Context, event eventv1.Event) error {
 	heading := fmt.Sprintf("%s %s/%s/%s", emoji, strings.ToLower(event.InvolvedObject.Kind),
 		event.InvolvedObject.Name, event.InvolvedObject.Namespace)
 	var metadata string
-	for k, v := range event.Metadata {
+	for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+		v := event.Metadata[k]
 		metadata = metadata + fmt.Sprintf("\\- *%s*: %s\n", escapeString(k), escapeString(v))
 	}
 	message := fmt.Sprintf("*%s*\n%s\n%s", escapeString(heading), escapeString(event.Message), metadata)
diff --git a/internal/notifier/webex.go b/internal/notifier/webex.go
index 65dd57893..92bb23374 100644
--- a/internal/notifier/webex.go
+++ b/internal/notifier/webex.go
@@ -20,7 +20,9 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -88,7 +90,8 @@ func (s *Webex) CreateMarkdown(event *eventv1.Event) string {
 	fmt.Fprintf(&b, "%s\n", event.Message)
 
 	if len(event.Metadata) > 0 {
-		for k, v := range event.Metadata {
+		for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+			v := event.Metadata[k]
 			fmt.Fprintf(&b, ">**%s**: %s\n", k, v)
 		}
 	}
diff --git a/internal/notifier/zoom.go b/internal/notifier/zoom.go
index 097614376..792bf9302 100644
--- a/internal/notifier/zoom.go
+++ b/internal/notifier/zoom.go
@@ -21,7 +21,9 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
+	"maps"
 	"net/url"
+	"slices"
 	"strings"
 
 	eventv1 "github.com/fluxcd/pkg/apis/event/v1beta1"
@@ -111,7 +113,8 @@ func (s *Zoom) Post(ctx context.Context, event eventv1.Event) error {
 
 	if len(event.Metadata) > 0 {
 		fields := make([]ZoomField, 0, len(event.Metadata))
-		for k, v := range event.Metadata {
+		for _, k := range slices.Sorted(maps.Keys(event.Metadata)) {
+			v := event.Metadata[k]
 			fields = append(fields, ZoomField{
 				Key:   k,
 				Value: v,