diff --git a/.gitrepo b/.gitrepo
index 09dd1d76..cb7951fb 100644
--- a/.gitrepo
+++ b/.gitrepo
@@ -6,7 +6,7 @@
 [subrepo]
 	remote = payments
 	branch = main
-	commit = ae1fa5ec4508bc3a7603bd15953228b6a6152761
-	parent = e11fe64274a7326f57cf409cd542ce7a08b05233
+	commit = e4c0f219fda7416c2a3d30fe7ec4184870134999
+	parent = b2827a506b6324812752e3689b2a4845480a397e
 	method = merge
 	cmdver = 0.4.5
diff --git a/internal/app/api/metadata.go b/internal/app/api/metadata.go
new file mode 100644
index 00000000..c65b0735
--- /dev/null
+++ b/internal/app/api/metadata.go
@@ -0,0 +1,54 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+
+	"github.com/pkg/errors"
+
+	"github.com/google/uuid"
+
+	"github.com/gorilla/mux"
+)
+
+type updateMetadataRepository interface {
+	UpdatePaymentMetadata(ctx context.Context, paymentID uuid.UUID, metadata map[string]string) error
+}
+
+type updateMetadataRequest map[string]string
+
+func updateMetadataHandler(repo updateMetadataRepository) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		paymentID, err := uuid.Parse(mux.Vars(r)["paymentID"])
+		if err != nil {
+			handleErrorBadRequest(w, r, err)
+
+			return
+		}
+
+		var metadata updateMetadataRequest
+
+		if r.ContentLength == 0 {
+			handleErrorBadRequest(w, r, errors.New("body is required"))
+
+			return
+		}
+
+		err = json.NewDecoder(r.Body).Decode(&metadata)
+		if err != nil {
+			handleError(w, r, err)
+
+			return
+		}
+
+		err = repo.UpdatePaymentMetadata(r.Context(), paymentID, metadata)
+		if err != nil {
+			handleError(w, r, err)
+
+			return
+		}
+
+		w.WriteHeader(http.StatusNoContent)
+	}
+}
diff --git a/internal/app/api/payments.go b/internal/app/api/payments.go
index abbf2e7e..80dfe1ed 100644
--- a/internal/app/api/payments.go
+++ b/internal/app/api/payments.go
@@ -34,18 +34,7 @@ type paymentResponse struct {
 	CreatedAt     time.Time                `json:"createdAt"`
 	Raw           interface{}              `json:"raw"`
 	Adjustments   []paymentAdjustment      `json:"adjustments"`
-	Metadata      []paymentMetadata        `json:"metadata"`
-}
-
-type paymentMetadata struct {
-	Key       string                     `json:"key"`
-	Value     string                     `json:"value"`
-	Changelog []paymentMetadataChangelog `json:"changelog"`
-}
-
-type paymentMetadataChangelog struct {
-	Timestamp string `json:"timestamp"`
-	Value     string `json:"value"`
+	Metadata      map[string]string        `json:"metadata"`
 }
 
 type paymentAdjustment struct {
@@ -139,19 +128,11 @@ func listPaymentsHandler(repo listPaymentsRepository) http.HandlerFunc {
 				}
 			}
 
-			for metadataIDx := range ret[i].Metadata {
-				data[i].Metadata = append(data[i].Metadata,
-					paymentMetadata{
-						Key:   ret[i].Metadata[metadataIDx].Key,
-						Value: ret[i].Metadata[metadataIDx].Value,
-					})
-
-				for changelogIdx := range ret[i].Metadata[metadataIDx].Changelog {
-					data[i].Metadata[metadataIDx].Changelog = append(data[i].Metadata[metadataIDx].Changelog,
-						paymentMetadataChangelog{
-							Timestamp: ret[i].Metadata[metadataIDx].Changelog[changelogIdx].CreatedAt.Format(time.RFC3339),
-							Value:     ret[i].Metadata[metadataIDx].Changelog[changelogIdx].Value,
-						})
+			if ret[i].Metadata != nil {
+				data[i].Metadata = make(map[string]string)
+
+				for metadataIDx := range ret[i].Metadata {
+					data[i].Metadata[ret[i].Metadata[metadataIDx].Key] = ret[i].Metadata[metadataIDx].Value
 				}
 			}
 		}
@@ -202,7 +183,6 @@ func readPaymentHandler(repo readPaymentRepository) http.HandlerFunc {
 			CreatedAt:     payment.CreatedAt,
 			Raw:           payment.RawData,
 			Adjustments:   make([]paymentAdjustment, len(payment.Adjustments)),
-			Metadata:      make([]paymentMetadata, len(payment.Metadata)),
 		}
 
 		if payment.AccountID != uuid.Nil {
@@ -219,19 +199,11 @@ func readPaymentHandler(repo readPaymentRepository) http.HandlerFunc {
 			}
 		}
 
-		for metadataIDx := range payment.Metadata {
-			data.Metadata = append(data.Metadata,
-				paymentMetadata{
-					Key:   payment.Metadata[metadataIDx].Key,
-					Value: payment.Metadata[metadataIDx].Value,
-				})
-
-			for changelogIdx := range payment.Metadata[metadataIDx].Changelog {
-				data.Metadata[metadataIDx].Changelog = append(data.Metadata[metadataIDx].Changelog,
-					paymentMetadataChangelog{
-						Timestamp: payment.Metadata[metadataIDx].Changelog[changelogIdx].CreatedAt.Format(time.RFC3339),
-						Value:     payment.Metadata[metadataIDx].Changelog[changelogIdx].Value,
-					})
+		if payment.Metadata != nil {
+			data.Metadata = make(map[string]string)
+
+			for metadataIDx := range payment.Metadata {
+				data.Metadata[payment.Metadata[metadataIDx].Key] = payment.Metadata[metadataIDx].Value
 			}
 		}
 
diff --git a/internal/app/api/router.go b/internal/app/api/router.go
index a1e68c9b..0c807539 100644
--- a/internal/app/api/router.go
+++ b/internal/app/api/router.go
@@ -36,6 +36,7 @@ func httpRouter(store *storage.Storage, serviceInfo api.ServiceInfo, connectorHa
 
 	authGroup.Path("/payments").Methods(http.MethodGet).Handler(listPaymentsHandler(store))
 	authGroup.Path("/payments/{paymentID}").Methods(http.MethodGet).Handler(readPaymentHandler(store))
+	authGroup.Path("/payments/{paymentID}/metadata").Methods(http.MethodPatch).Handler(updateMetadataHandler(store))
 
 	authGroup.Path("/accounts").Methods(http.MethodGet).Handler(listAccountsHandler(store))
 
diff --git a/internal/app/models/metadata.go b/internal/app/models/metadata.go
index fdfbb41b..730aa19c 100644
--- a/internal/app/models/metadata.go
+++ b/internal/app/models/metadata.go
@@ -16,11 +16,11 @@ type Metadata struct {
 	Key       string    `bun:",pk,nullzero"`
 	Value     string
 
-	Changelog []MetadataChangelog `bun:",pk,nullzero"`
+	Changelog []MetadataChangelog `bun:",nullzero"`
 	Payment   *Payment            `bun:"rel:has-one,join:payment_id=id"`
 }
 
 type MetadataChangelog struct {
-	CreatedAt time.Time
-	Value     string
+	CreatedAt time.Time `json:"createdAt"`
+	Value     string    `json:"value"`
 }
diff --git a/internal/app/storage/metadata.go b/internal/app/storage/metadata.go
new file mode 100644
index 00000000..853229f8
--- /dev/null
+++ b/internal/app/storage/metadata.go
@@ -0,0 +1,39 @@
+package storage
+
+import (
+	"context"
+	"time"
+
+	"github.com/formancehq/payments/internal/app/models"
+	"github.com/google/uuid"
+)
+
+func (s *Storage) UpdatePaymentMetadata(ctx context.Context, paymentID uuid.UUID, metadata map[string]string) error {
+	var metadataToInsert []models.Metadata // nolint:prealloc // it's against a map
+
+	for key, value := range metadata {
+		metadataToInsert = append(metadataToInsert, models.Metadata{
+			PaymentID: paymentID,
+			Key:       key,
+			Value:     value,
+			Changelog: []models.MetadataChangelog{
+				{
+					CreatedAt: time.Now(),
+					Value:     value,
+				},
+			},
+		})
+	}
+
+	_, err := s.db.NewInsert().
+		Model(&metadataToInsert).
+		On("CONFLICT (payment_id, key) DO UPDATE").
+		Set("value = EXCLUDED.value").
+		Set("changelog = metadata.changelog || EXCLUDED.changelog").
+		Exec(ctx)
+	if err != nil {
+		return e("failed to update payment metadata", err)
+	}
+
+	return nil
+}
diff --git a/internal/app/storage/payments.go b/internal/app/storage/payments.go
index 320eb488..10f09662 100644
--- a/internal/app/storage/payments.go
+++ b/internal/app/storage/payments.go
@@ -156,7 +156,7 @@ func (s *Storage) UpsertPayments(ctx context.Context, provider models.ConnectorP
 			Model(&metadata).
 			On("CONFLICT (payment_id, key) DO UPDATE").
 			Set("value = EXCLUDED.value").
-			Set("changelog = changelog || EXCLUDED.changelog").
+			Set("changelog = metadata.changelog || EXCLUDED.changelog").
 			Exec(ctx)
 		if err != nil {
 			return e("failed to create metadata", err)
diff --git a/openapi.yaml b/openapi.yaml
index 6eeca419..78247737 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -36,6 +36,19 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/Payment'
+  /payments/{paymentId}/metadata:
+    patch:
+      summary: Update metadata
+      tags:
+        - Payments
+      operationId: updateMetadata
+      parameters:
+        - $ref: '#/components/parameters/PaymentId'
+      requestBody:
+        $ref: '#/components/requestBodies/UpdateMetadata'
+      responses:
+        '204':
+          $ref: '#/components/responses/NoContent'
   /accounts:
       get:
         summary: List accounts
@@ -147,7 +160,7 @@ paths:
       responses:
         '200':
           $ref: '#/components/responses/Task'
-  /connectors/stripe/transfer:
+  /connectors/stripe/transfers:
     post:
       summary: Transfer funds between Stripe accounts
       tags:
@@ -298,6 +311,12 @@ components:
         application/json:
           schema:
             $ref: '#/components/schemas/StripeTransferRequest'
+    UpdateMetadata:
+      required: true
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/PaymentMetadata'
 
   # ---------------------- SCHEMAS ----------------------
   schemas:
@@ -644,9 +663,7 @@ components:
           items:
             $ref: '#/components/schemas/PaymentAdjustment'
         metadata:
-          type: array
-          items:
-            $ref: '#/components/schemas/PaymentMetadata'
+          $ref: '#/components/schemas/PaymentMetadata'
     PaymentAdjustment:
         type: object
         required:
@@ -672,27 +689,9 @@ components:
             type: boolean
     PaymentMetadata:
       type: object
-      required:
-        - key
-        - value
       properties:
         key:
           type: string
-        value:
-          type: string
-        changelog:
-          $ref: '#/components/schemas/PaymentMetadataChangelog'
-    PaymentMetadataChangelog:
-      type: object
-      required:
-        - timestamp
-        - value
-      properties:
-        timestamp:
-          type: string
-          format: date-time
-        value:
-          type: string
     Account:
       type: object
       required:
@@ -870,6 +869,7 @@ components:
         - ACTIVE
         - TERMINATED
         - FAILED
+        - SUCCEEDED
     ServerInfo:
       type: object
       required: