diff --git a/metrics_quotas.go b/metrics_quotas.go
index 8675126..590de6f 100644
--- a/metrics_quotas.go
+++ b/metrics_quotas.go
@@ -13,21 +13,21 @@ func (h *HarborExporter) collectQuotasMetric(ch chan<- prometheus.Metric) bool {
 	start := time.Now()
 
 	type quotaMetric []struct {
-		ID  float64
+		ID  float64 `json:"id"`
 		Ref struct {
-			ID        float64
-			Name      string
-			OwnerName string
+			ID        float64 `json:"id"`
+			Name      string  `json:"name"`
+			OwnerName string  `json:"owner_name"`
 		}
 		CreationTime time.Time
 		UpdateTime   time.Time
 		Hard         struct {
-			Count   float64
-			Storage float64
+			Count   float64 `json:"count"`
+			Storage float64 `json:"storage"`
 		}
 		Used struct {
-			Count   float64
-			Storage float64
+			Count   float64 `json:"count"`
+			Storage float64 `json:"storage"`
 		}
 	}
 	var data quotaMetric
diff --git a/metrics_replications.go b/metrics_replications.go
index 9793a19..83be3fc 100644
--- a/metrics_replications.go
+++ b/metrics_replications.go
@@ -12,20 +12,20 @@ import (
 func (h *HarborExporter) collectReplicationsMetric(ch chan<- prometheus.Metric) bool {
 	start := time.Now()
 	type policiesMetrics []struct {
-		ID      float64
-		Name    string
-		Enabled bool
+		ID      float64 `json:"id"`
+		Name    string  `json:"name"`
+		Enabled bool    `json:"enabled"`
 		Trigger struct {
-			Type string
+			Type string `json:"type"`
 		}
 		// Extra fields omitted for maintainability: not relevant for current metrics
 	}
 	type policyMetric []struct {
-		Status     string
-		Failed     float64
-		Succeed    float64
-		InProgress float64
-		Stopped    float64
+		Status     string  `json:"status"`
+		Failed     float64 `json:"failed"`
+		Succeed    float64 `json:"succeed"`
+		InProgress float64 `json:"in_progress"`
+		Stopped    float64 `json:"stopped"`
 		// Extra fields omitted for maintainability: not relevant for current metrics
 	}
 
diff --git a/metrics_repositories.go b/metrics_repositories.go
index d59b36c..42c3e5d 100644
--- a/metrics_repositories.go
+++ b/metrics_repositories.go
@@ -12,43 +12,43 @@ import (
 func (h *HarborExporter) collectRepositoriesMetric(ch chan<- prometheus.Metric) bool {
 	start := time.Now()
 	type projectsMetrics []struct {
-		ProjectID  float64
-		OwnerID    float64
-		Name       string
-		RepoCount  float64
-		ChartCount float64
+		ProjectID  float64 `json:"project_id"`
+		OwnerID    float64 `json:"owner_id"`
+		Name       string  `json:"name"`
+		RepoCount  float64 `json:"repo_count"`
+		ChartCount float64 `json:"chart_count"`
 	}
 	type repositoriesMetric []struct {
-		ID           float64
-		Name         string
-		ProjectID    float64
-		Description  string
-		PullCount    float64
-		StarCount    float64
-		TagsCount    float64
-		CreationTime time.Time
-		UpdateTime   time.Time
+		ID           float64   `json:"id"`
+		Name         string    `json:"name"`
+		ProjectID    float64   `json:"project_id"`
+		Description  string    `json:"description"`
+		PullCount    float64   `json:"pull_count"`
+		StarCount    float64   `json:"star_count"`
+		TagsCount    float64   `json:"tags_count"`
+		CreationTime time.Time `json:"creation_time"`
+		UpdateTime   time.Time `json:"update_time"`
 		labels       []struct {
-			ID           float64
-			Name         string
-			ProjectID    float64
-			Description  string
-			Color        string
-			Deleted      bool
-			Scope        string
-			CreationTime time.Time
-			UpdateTime   time.Time
+			ID           float64   `json:"id"`
+			Name         string    `json:"name"`
+			ProjectID    float64   `json:"project_id"`
+			Description  string    `json:"description"`
+			Color        string    `json:"color"`
+			Deleted      bool      `json:"deleted"`
+			Scope        string    `json:"scope"`
+			CreationTime time.Time `json:"creation_time"`
+			UpdateTime   time.Time `json:"update_time"`
 		}
 	}
 	type repositoriesMetricV2 []struct {
-		ID            float64
-		Name          string
-		ProjectID     float64
-		Description   string
-		PullCount     float64
-		ArtifactCount float64
-		CreationTime  time.Time
-		UpdateTime    time.Time
+		ID            float64   `json:"id"`
+		Name          string    `json:"name"`
+		ProjectID     float64   `json:"project_id"`
+		Description   string    `json:"description"`
+		PullCount     float64   `json:"pull_count"`
+		ArtifactCount float64   `json:"artifact_count"`
+		CreationTime  time.Time `json:"creation_time"`
+		UpdateTime    time.Time `json:"update_time"`
 	}
 	var projectsData projectsMetrics
 	err := h.requestAll("/projects", func(pageBody []byte) error {
diff --git a/metrics_statistics.go b/metrics_statistics.go
index f636023..dc3eb68 100644
--- a/metrics_statistics.go
+++ b/metrics_statistics.go
@@ -12,12 +12,12 @@ func (h *HarborExporter) collectStatisticsMetric(ch chan<- prometheus.Metric) bo
 	start := time.Now()
 
 	type statisticsMetric struct {
-		TotalProjectCount   float64
-		PublicProjectCount  float64
-		PrivateProjectCount float64
-		PublicRepoCount     float64
-		TotalRepoCount      float64
-		PrivateRepoCount    float64
+		TotalProjectCount   float64 `json:"total_project_count"`
+		PublicProjectCount  float64 `json:"public_project_count"`
+		PrivateProjectCount float64 `json:"private_project_count"`
+		PublicRepoCount     float64 `json:"public_repo_count"`
+		TotalRepoCount      float64 `json:"total_repo_count"`
+		PrivateRepoCount    float64 `json:"private_repo_count"`
 	}
 
 	body, _ := h.request("/statistics")