diff --git a/helm-overrides/k8s-admin-prd-ase1/postgresql/custom-values.yaml b/helm-overrides/k8s-admin-prd-ase1/postgresql/custom-values.yaml
new file mode 100644
index 0000000..3a60ac0
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+++ b/helm-overrides/k8s-admin-prd-ase1/postgresql/custom-values.yaml
@@ -0,0 +1,48 @@
+# PostgreSQL for toolshed's control plane.
+#
+# Deployed as shared infrastructure in its own namespace rather than inside
+# the toolshed namespace, so it is addressed over cluster DNS like any other
+# platform component and its lifecycle is independent of the application
+# that happens to be its first consumer:
+#
+#   postgresql.postgres.svc.cluster.local:5432
+#
+# Credentials come from Vault through External Secrets — see
+# devops-infra-argo-config/secretstores/toolshed-postgres-credentials.yaml.
+# The Secret must exist before this pod can start; a missing Secret leaves it
+# in CreateContainerConfigError rather than failing in a way that explains
+# itself.
+
+fullnameOverride: postgresql
+
+image:
+  repository: postgres
+  tag: "16-alpine"
+  pullPolicy: IfNotPresent
+
+existingSecret: postgresql-credentials
+database: toolshed
+
+persistence:
+  enabled: true
+  # local-path-provisioner, this cluster's default StorageClass — installed
+  # right after Cilium precisely because kubeadm ships no default (unlike
+  # k3s). 5Gi is generous for control-plane metadata; the volume is not
+  # resizable in place with this provisioner, so it is sized up front.
+  storageClass: local-path
+  size: 5Gi
+
+config:
+  # Deliberately far below PostgreSQL's 128MB default. The node has 8GB and
+  # was already at its ceiling before this; the demo apps were scaled to zero
+  # to make room. Revisit only if query performance actually suffers, which
+  # for a handful of control-plane tables it will not.
+  sharedBuffers: 32MB
+  maxConnections: "50"
+
+resources:
+  requests:
+    cpu: 50m
+    memory: 64Mi
+  limits:
+    memory: 256Mi
diff --git a/helm-templates/postgresql/Chart.yaml b/helm-templates/postgresql/Chart.yaml
new file mode 100644
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+++ b/helm-templates/postgresql/Chart.yaml
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+apiVersion: v2
+name: postgresql
+description: |
+  Single-instance PostgreSQL for this homelab.
+
+  Hand-written rather than vendoring Bitnami's chart: Broadcom has been
+  retiring and freezing images behind that repo (see claude.md infra issue
+  #4, where it broke Contour twice), and PostgreSQL publishes no official
+  Helm chart of its own. A single StatefulSet with one PVC is small enough
+  that owning it outright costs less than depending on an unstable
+  repackage.
+
+  Not highly available and not intended to be. One replica, one PVC, no
+  replication, no connection pooler. Adding any of those to a single-node
+  cluster would be theatre.
+type: application
+version: 0.1.0
+appVersion: "16"
diff --git a/helm-templates/postgresql/templates/service.yaml b/helm-templates/postgresql/templates/service.yaml
new file mode 100644
index 0000000..d7c2b1b
--- /dev/null
+++ b/helm-templates/postgresql/templates/service.yaml
@@ -0,0 +1,23 @@
+{{- $name := .Values.fullnameOverride | default "postgresql" -}}
+# ClusterIP only. Nothing outside the cluster should reach the database, and
+# there is no Ingress here on purpose — Contour terminates HTTP, and exposing
+# PostgreSQL's wire protocol through it is neither possible nor wanted.
+#
+# Consumers address this as:
+#   {{ $name }}.{{ .Release.Namespace }}.svc.cluster.local:{{ .Values.service.port }}
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ $name }}
+  namespace: {{ .Release.Namespace }}
+  labels:
+    app: {{ $name }}
+spec:
+  type: ClusterIP
+  selector:
+    app: {{ $name }}
+  ports:
+    - name: postgres
+      port: {{ .Values.service.port }}
+      targetPort: postgres
+      protocol: TCP
diff --git a/helm-templates/postgresql/templates/statefulset.yaml b/helm-templates/postgresql/templates/statefulset.yaml
new file mode 100644
index 0000000..544819f
--- /dev/null
+++ b/helm-templates/postgresql/templates/statefulset.yaml
@@ -0,0 +1,89 @@
+{{- $name := .Values.fullnameOverride | default "postgresql" -}}
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: {{ $name }}
+  namespace: {{ .Release.Namespace }}
+  labels:
+    app: {{ $name }}
+spec:
+  serviceName: {{ $name }}
+  replicas: 1
+  selector:
+    matchLabels:
+      app: {{ $name }}
+  template:
+    metadata:
+      labels:
+        app: {{ $name }}
+    spec:
+      securityContext:
+        # The official image starts as root, initialises the data directory,
+        # then drops to the postgres user (uid 70 on the Alpine variant).
+        # fsGroup makes the provisioned volume group-writable so that drop
+        # still leaves the data directory usable.
+        fsGroup: 70
+      terminationGracePeriodSeconds: 60
+      containers:
+        - name: postgres
+          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
+          args:
+            - -c
+            - shared_buffers={{ .Values.config.sharedBuffers }}
+            - -c
+            - max_connections={{ .Values.config.maxConnections }}
+          env:
+            - name: POSTGRES_USER
+              valueFrom:
+                secretKeyRef:
+                  name: {{ .Values.existingSecret }}
+                  key: {{ .Values.secretKeys.username }}
+            - name: POSTGRES_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: {{ .Values.existingSecret }}
+                  key: {{ .Values.secretKeys.password }}
+            - name: POSTGRES_DB
+              value: {{ .Values.database | quote }}
+            # PGDATA must be a SUBDIRECTORY of the mount, not the mount
+            # itself: initdb refuses to run in a directory that already has
+            # contents, and a freshly provisioned volume is not always empty.
+            - name: PGDATA
+              value: /var/lib/postgresql/data/pgdata
+          ports:
+            - name: postgres
+              containerPort: 5432
+              protocol: TCP
+          # Run through a shell so the environment expands — Kubernetes does
+          # not substitute $(VAR) inside exec probe commands.
+          readinessProbe:
+            exec:
+              command: ["sh", "-c", 'pg_isready -U "$POSTGRES_USER" -d "$POSTGRES_DB" -h 127.0.0.1']
+            initialDelaySeconds: 10
+            periodSeconds: 10
+            timeoutSeconds: 5
+            failureThreshold: 6
+          livenessProbe:
+            exec:
+              command: ["sh", "-c", 'pg_isready -U "$POSTGRES_USER" -d "$POSTGRES_DB" -h 127.0.0.1']
+            initialDelaySeconds: 30
+            periodSeconds: 20
+            timeoutSeconds: 5
+            failureThreshold: 6
+          resources:
+            {{- toYaml .Values.resources | nindent 12 }}
+          volumeMounts:
+            - name: data
+              mountPath: /var/lib/postgresql/data
+{{- if .Values.persistence.enabled }}
+  volumeClaimTemplates:
+    - metadata:
+        name: data
+      spec:
+        accessModes: ["ReadWriteOnce"]
+        storageClassName: {{ .Values.persistence.storageClass | quote }}
+        resources:
+          requests:
+            storage: {{ .Values.persistence.size | quote }}
+{{- end }}
diff --git a/helm-templates/postgresql/values.yaml b/helm-templates/postgresql/values.yaml
new file mode 100644
index 0000000..2b27b07
--- /dev/null
+++ b/helm-templates/postgresql/values.yaml
@@ -0,0 +1,45 @@
+# Chart defaults. Real configuration lives in
+# helm-overrides/k8s-admin-prd-ase1/postgresql/custom-values.yaml.
+
+fullnameOverride: postgresql
+
+image:
+  # Pulled from Docker Hub, like every other infra component here (gitea,
+  # vault, harbor). The base-images mirror in Harbor exists to remove
+  # Docker Hub from the *application build* path and to minimise shipped
+  # app images — it is not in play for platform components.
+  repository: postgres
+  tag: "16-alpine"
+  pullPolicy: IfNotPresent
+
+# Name of the Secret holding username/password. Created by External
+# Secrets from Vault, not by this chart — a chart that generates its own
+# database password regenerates it on every render, which silently locks
+# you out of an existing volume.
+existingSecret: postgresql-credentials
+secretKeys:
+  username: username
+  password: password
+
+database: toolshed
+
+service:
+  port: 5432
+
+persistence:
+  enabled: true
+  storageClass: local-path
+  size: 5Gi
+
+# Tuned down hard. The box has 8GB total and is at its ceiling; PostgreSQL's
+# default shared_buffers of 128MB is most of this pod's budget on its own.
+config:
+  sharedBuffers: 32MB
+  maxConnections: "50"
+
+resources:
+  requests:
+    cpu: 50m
+    memory: 64Mi
+  limits:
+    memory: 256Mi