diff --git a/server/cmd/dev-seed/main.go b/server/cmd/dev-seed/main.go
index 5401191..e1a8ae5 100644
--- a/server/cmd/dev-seed/main.go
+++ b/server/cmd/dev-seed/main.go
@@ -707,17 +707,19 @@ func clearMonitoringData(ctx context.Context, tx pgx.Tx, state *seedState) error
 	singles := []string{
 		`DELETE FROM monitoring_platform_access_snapshots WHERE tenant_id = $1`,
 		`DELETE FROM monitoring_article_url_aliases WHERE tenant_id = $1`,
-		`DELETE FROM site_domain_mappings WHERE tenant_id = $1`,
 	}
 	for _, query := range singles {
 		if _, err := tx.Exec(ctx, query, state.TenantID); err != nil {
 			return wrapSeedErr("clear monitoring data", err)
 		}
 	}
+	if _, err := tx.Exec(ctx, `DELETE FROM site_domain_mappings`); err != nil {
+		return wrapSeedErr("clear site mappings", err)
+	}
 	return nil
 }
 
-func insertSiteMappings(ctx context.Context, tx pgx.Tx, tenantID int64) error {
+func insertSiteMappings(ctx context.Context, tx pgx.Tx, _ int64) error {
 	mappings := []struct {
 		domain   string
 		siteKey  string
@@ -729,9 +731,14 @@ func insertSiteMappings(ctx context.Context, tx pgx.Tx, tenantID int64) error {
 	}
 	for _, item := range mappings {
 		if _, err := tx.Exec(ctx, `
-			INSERT INTO site_domain_mappings (tenant_id, registrable_domain, site_key, site_name, is_active)
-			VALUES ($1, $2, $3, $4, TRUE)
-		`, tenantID, item.domain, item.siteKey, item.siteName); err != nil {
+			INSERT INTO site_domain_mappings (registrable_domain, site_key, site_name, is_active)
+			VALUES ($1, $2, $3, TRUE)
+			ON CONFLICT (registrable_domain) DO UPDATE
+			SET site_key = EXCLUDED.site_key,
+				site_name = EXCLUDED.site_name,
+				is_active = EXCLUDED.is_active,
+				updated_at = NOW()
+		`, item.domain, item.siteKey, item.siteName); err != nil {
 			return wrapSeedErr("insert site mapping", err)
 		}
 	}
diff --git a/server/internal/ops/domain/types.go b/server/internal/ops/domain/types.go
index 46fd74d..7af5bc3 100644
--- a/server/internal/ops/domain/types.go
+++ b/server/internal/ops/domain/types.go
@@ -63,3 +63,13 @@ type AuditLogFilter struct {
 	Limit      int
 	Offset     int
 }
+
+type SiteDomainMapping struct {
+	ID                 int64
+	RegistrableDomain string
+	SiteKey            string
+	SiteName           string
+	IsActive           bool
+	CreatedAt          time.Time
+	UpdatedAt          time.Time
+}
diff --git a/server/migrations_monitoring/20260410103000_create_monitoring_tables.up.sql b/server/migrations_monitoring/20260410103000_create_monitoring_tables.up.sql
index c7487e4..96353c3 100644
--- a/server/migrations_monitoring/20260410103000_create_monitoring_tables.up.sql
+++ b/server/migrations_monitoring/20260410103000_create_monitoring_tables.up.sql
@@ -152,16 +152,22 @@ CREATE INDEX idx_citation_facts_run
 
 CREATE TABLE site_domain_mappings (
     id                 BIGSERIAL PRIMARY KEY,
-    tenant_id          BIGINT,
     registrable_domain VARCHAR(255) NOT NULL,
     site_key           VARCHAR(255) NOT NULL,
     site_name          VARCHAR(255) NOT NULL,
     is_active          BOOLEAN NOT NULL DEFAULT true,
-    created_at         TIMESTAMPTZ NOT NULL DEFAULT NOW()
+    created_at         TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at         TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
 
-CREATE INDEX idx_site_domain_mappings_lookup
-    ON site_domain_mappings(tenant_id, registrable_domain, is_active);
+CREATE UNIQUE INDEX uk_site_domain_mappings_domain
+    ON site_domain_mappings(registrable_domain);
+
+CREATE INDEX idx_site_domain_mappings_active_domain
+    ON site_domain_mappings(registrable_domain) WHERE is_active = TRUE;
+
+CREATE INDEX idx_site_domain_mappings_created
+    ON site_domain_mappings(created_at DESC, id DESC);
 
 CREATE TABLE monitoring_article_url_aliases (
     id                             BIGSERIAL PRIMARY KEY,
diff --git a/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.down.sql b/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.down.sql
new file mode 100644
index 0000000..c211014
--- /dev/null
+++ b/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.down.sql
@@ -0,0 +1,10 @@
+DROP INDEX IF EXISTS idx_site_domain_mappings_created;
+DROP INDEX IF EXISTS idx_site_domain_mappings_active_domain;
+DROP INDEX IF EXISTS uk_site_domain_mappings_domain;
+
+ALTER TABLE site_domain_mappings
+    ADD COLUMN IF NOT EXISTS tenant_id BIGINT,
+    DROP COLUMN IF EXISTS updated_at;
+
+CREATE INDEX IF NOT EXISTS idx_site_domain_mappings_lookup
+    ON site_domain_mappings(tenant_id, registrable_domain, is_active);
diff --git a/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.up.sql b/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.up.sql
new file mode 100644
index 0000000..0ac702f
--- /dev/null
+++ b/server/migrations_monitoring/20260429110000_globalize_site_domain_mappings.up.sql
@@ -0,0 +1,24 @@
+UPDATE site_domain_mappings
+SET registrable_domain = LOWER(TRIM(registrable_domain)),
+    site_key = LOWER(TRIM(site_key)),
+    site_name = TRIM(site_name);
+
+DELETE FROM site_domain_mappings older
+USING site_domain_mappings newer
+WHERE older.registrable_domain = newer.registrable_domain
+  AND older.id < newer.id;
+
+DROP INDEX IF EXISTS idx_site_domain_mappings_lookup;
+
+ALTER TABLE site_domain_mappings
+    DROP COLUMN IF EXISTS tenant_id,
+    ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW();
+
+CREATE UNIQUE INDEX IF NOT EXISTS uk_site_domain_mappings_domain
+    ON site_domain_mappings(registrable_domain);
+
+CREATE INDEX IF NOT EXISTS idx_site_domain_mappings_active_domain
+    ON site_domain_mappings(registrable_domain) WHERE is_active = TRUE;
+
+CREATE INDEX IF NOT EXISTS idx_site_domain_mappings_created
+    ON site_domain_mappings(created_at DESC, id DESC);