diff --git a/apps/server/.env.example b/apps/server/.env.example
index b954015..9c9069f 100644
--- a/apps/server/.env.example
+++ b/apps/server/.env.example
@@ -25,10 +25,9 @@ EVENT_SIGNING_KEY=
 # rotate without fracturing the signed chain. Generate with:  openssl rand -hex 32
 # Escrow it offsite (alongside EVENT_SIGNING_KEY) — recovery needs both, and neither is ever
 # stored inside the backup it unlocks. Backups stay a no-op until BOTH this key and an in-UI
-# target directory are set.
+# target directory are set. The target directory AND retention (keep-last / keep-daily) are
+# admin-chosen in the UI (Setup → Backup), NOT env — only this key is an env secret.
 #   BACKUP_KEY=
-#   BACKUP_KEEP_LAST=7                # keep this many newest backups always
-#   BACKUP_KEEP_DAILY_DAYS=30         # plus one-per-day within this window
 
 # Optional ----------------------------------------------------------------
 # PORT=3000
diff --git a/apps/server/src/backup-service.ts b/apps/server/src/backup-service.ts
index 0535a87..9a4a507 100644
--- a/apps/server/src/backup-service.ts
+++ b/apps/server/src/backup-service.ts
@@ -3,7 +3,7 @@ import { access, stat } from "node:fs/promises";
 import { resolve } from "node:path";
 import { eq, siteConfig, type Db } from "@parking/db";
 import type { FastifyBaseLogger } from "fastify";
-import { DEFAULT_BACKUP_RETENTION, runBackup, type BackupResult } from "./backup.js";
+import { DEFAULT_BACKUP_RETENTION, runBackup, type BackupResult, type BackupRetention } from "./backup.js";
 
 // Thin coordinator around the backup engine (backup.ts). The TARGET DIRECTORY is admin-chosen
 // and stored in site_config.backup_target_dir (read fresh each run, so changing it in the UI
@@ -28,6 +28,9 @@ export interface BackupStatus {
   readonly configured: boolean;
   /** The admin-chosen target dir (null if unset) — surfaced so the UI can show/edit it. */
   readonly targetDir: string | null;
+  /** Admin-tuned retention (resolved: DB value or code default) — surfaced for the UI form. */
+  readonly keepLast: number;
+  readonly keepDailyDays: number;
   /** Whether the env key is present + long enough (the UI flags a missing key distinctly). */
   readonly keyPresent: boolean;
   readonly running: boolean;
@@ -79,6 +82,18 @@ export class BackupService {
     return dir ? dir : null;
   }
 
+  /** Resolved retention from site_config, falling back to the code default per field. Read fresh. */
+  retention(): BackupRetention {
+    const row = this.#db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
+    const keepLast = row?.backupKeepLast;
+    const keepDailyDays = row?.backupKeepDailyDays;
+    return {
+      keepLast: keepLast != null && keepLast >= 0 ? keepLast : DEFAULT_BACKUP_RETENTION.keepLast,
+      keepDailyDays:
+        keepDailyDays != null && keepDailyDays >= 0 ? keepDailyDays : DEFAULT_BACKUP_RETENTION.keepDailyDays,
+    };
+  }
+
   get keyPresent(): boolean {
     return backupKeyFromEnv().length >= 16;
   }
@@ -88,9 +103,12 @@ export class BackupService {
   }
 
   status(): BackupStatus {
+    const r = this.retention();
     return {
       configured: this.configured,
       targetDir: this.targetDir(),
+      keepLast: r.keepLast,
+      keepDailyDays: r.keepDailyDays,
       keyPresent: this.keyPresent,
       running: this.#running,
       lastSuccessAt: this.#lastSuccessAt,
@@ -120,7 +138,7 @@ export class BackupService {
     this.#inflight = (async () => {
       try {
         this.#logger?.info(`backup: starting (${trigger}) → ${targetDir}`);
-        const res = await runBackup(this.#db, { targetDir, key, retention: DEFAULT_BACKUP_RETENTION }, this.#logger);
+        const res = await runBackup(this.#db, { targetDir, key, retention: this.retention() }, this.#logger);
         this.#lastResult = res;
         this.#lastSuccessAt = new Date().toISOString();
         this.#lastError = null;
diff --git a/apps/server/src/backup.ts b/apps/server/src/backup.ts
index 06d9e1e..8a857cb 100644
--- a/apps/server/src/backup.ts
+++ b/apps/server/src/backup.ts
@@ -40,9 +40,11 @@ export interface BackupRetention {
   readonly keepDailyDays: number;
 }
 
+// Code defaults — the fallback when the admin hasn't set a value in site_config (the source of
+// truth). NOT env-driven: retention is operational policy tuned from the Backup screen.
 export const DEFAULT_BACKUP_RETENTION: BackupRetention = {
-  keepLast: Number(process.env.BACKUP_KEEP_LAST ?? 7),
-  keepDailyDays: Number(process.env.BACKUP_KEEP_DAILY_DAYS ?? 30),
+  keepLast: 7,
+  keepDailyDays: 30,
 };
 
 export interface BackupOptions {
diff --git a/apps/server/src/routes/backup.routes.test.ts b/apps/server/src/routes/backup.routes.test.ts
index afd8b24..7c3e779 100644
--- a/apps/server/src/routes/backup.routes.test.ts
+++ b/apps/server/src/routes/backup.routes.test.ts
@@ -50,6 +50,8 @@ describe("GET /api/backup/status", () => {
     expect(body).toMatchObject({
       configured: false,
       targetDir: null,
+      keepLast: 7, // code defaults surfaced when unset
+      keepDailyDays: 30,
       running: false,
       lastSuccessAt: null,
       lastError: null,
@@ -99,6 +101,37 @@ describe("PUT /api/backup/config — admin-chosen target", () => {
     });
     expect(clear.json().targetDir).toBeNull();
   });
+
+  it("persists retention and resets to defaults on null", async () => {
+    const { username, password } = await seedUser(db, { username: "boss", roleId: "admin" });
+    const { cookie, csrf } = await login(app, username, password);
+
+    const set = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: 3, keepDailyDays: 14 },
+    });
+    expect(set.json()).toMatchObject({ keepLast: 3, keepDailyDays: 14 });
+
+    // null resets to the code default.
+    const reset = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: null, keepDailyDays: null },
+    });
+    expect(reset.json()).toMatchObject({ keepLast: 7, keepDailyDays: 30 });
+  });
+
+  it("rejects a negative retention value (400)", async () => {
+    const { username, password } = await seedUser(db, { username: "boss", roleId: "admin" });
+    const { cookie, csrf } = await login(app, username, password);
+    const res = await app.inject({
+      method: "PUT", url: "/api/backup/config",
+      headers: { cookie, "x-csrf-token": csrf },
+      payload: { keepLast: -1 },
+    });
+    expect(res.statusCode).toBe(400);
+  });
 });
 
 describe("POST /api/backup/test — path probe", () => {
diff --git a/apps/server/src/routes/backup.ts b/apps/server/src/routes/backup.ts
index ecc2a97..144ef98 100644
--- a/apps/server/src/routes/backup.ts
+++ b/apps/server/src/routes/backup.ts
@@ -13,6 +13,10 @@ import { checkTargetDir, type BackupService } from "../backup-service.js";
 
 interface ConfigBody {
   targetDir?: string | null;
+  /** Retention: keep this many newest backups. null = reset to the code default. */
+  keepLast?: number | null;
+  /** Retention: keep one-per-day within this many days. null = reset to the code default. */
+  keepDailyDays?: number | null;
 }
 interface TestBody {
   targetDir?: string;
@@ -28,18 +32,37 @@ export async function backupRoutes(app: FastifyInstance, db: Db, backups: Backup
     "/api/backup/config",
     { preHandler: requirePermission("backup:update") },
     async (req, reply) => {
-      const raw = req.body?.targetDir;
-      if (raw != null && typeof raw !== "string") {
-        return reply.code(400).send({ error: "targetDir must be a string or null" });
+      const body = req.body ?? {};
+      const patch: { backupTargetDir?: string | null; backupKeepLast?: number | null; backupKeepDailyDays?: number | null } = {};
+
+      if ("targetDir" in body) {
+        const raw = body.targetDir;
+        if (raw != null && typeof raw !== "string") {
+          return reply.code(400).send({ error: "targetDir must be a string or null" });
+        }
+        patch.backupTargetDir = raw == null ? null : raw.trim() || null;
       }
-      const next = raw == null ? null : raw.trim() || null;
+      // Retention: a non-negative integer, or null to reset to the code default.
+      for (const [field, col] of [
+        ["keepLast", "backupKeepLast"],
+        ["keepDailyDays", "backupKeepDailyDays"],
+      ] as const) {
+        if (field in body) {
+          const v = body[field];
+          if (v != null && (!Number.isInteger(v) || v < 0)) {
+            return reply.code(400).send({ error: `${field} must be a non-negative integer or null` });
+          }
+          patch[col] = v ?? null;
+        }
+      }
+
       const updatedAt = new Date().toISOString();
       // Single-row site_config (id=1): upsert, since a fresh install may not have it yet.
       const existing = db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
       if (existing) {
-        db.update(siteConfig).set({ backupTargetDir: next, updatedAt }).where(eq(siteConfig.id, 1)).run();
+        db.update(siteConfig).set({ ...patch, updatedAt }).where(eq(siteConfig.id, 1)).run();
       } else {
-        db.insert(siteConfig).values({ id: 1, backupTargetDir: next, updatedAt }).run();
+        db.insert(siteConfig).values({ id: 1, ...patch, updatedAt }).run();
       }
       return backups.status();
     },
diff --git a/apps/web/src/BackupSettings.tsx b/apps/web/src/BackupSettings.tsx
index f098f79..2568f19 100644
--- a/apps/web/src/BackupSettings.tsx
+++ b/apps/web/src/BackupSettings.tsx
@@ -5,7 +5,7 @@ import {
   ApiError,
   fetchBackupStatus,
   runBackup,
-  setBackupTarget,
+  setBackupConfig,
   testBackupTarget,
   type BackupStatus,
   type TargetCheck,
@@ -56,6 +56,8 @@ export function BackupSettings() {
   const qc = useQueryClient();
   const [toast, setToast] = useState<{ kind: "ok" | "err"; msg: string } | null>(null);
   const [target, setTarget] = useState("");
+  const [keepLast, setKeepLast] = useState("");
+  const [keepDaily, setKeepDaily] = useState("");
   const [check, setCheck] = useState<{ kind: "ok" | "err"; msg: string } | null>(null);
 
   const q = useQuery({
@@ -65,13 +67,22 @@ export function BackupSettings() {
   });
   const status = q.data;
 
-  // Seed the editable field from the saved value once it loads (and when it changes server-side).
+  // Seed the editable fields from the saved values once they load (and on server-side change).
   useEffect(() => {
-    if (status) setTarget(status.targetDir ?? "");
-  }, [status?.targetDir]);
+    if (status) {
+      setTarget(status.targetDir ?? "");
+      setKeepLast(String(status.keepLast));
+      setKeepDaily(String(status.keepDailyDays));
+    }
+  }, [status?.targetDir, status?.keepLast, status?.keepDailyDays]);
 
   const save = useMutation({
-    mutationFn: () => setBackupTarget(target.trim() || null),
+    mutationFn: () =>
+      setBackupConfig({
+        targetDir: target.trim() || null,
+        keepLast: keepLast.trim() === "" ? null : Number(keepLast),
+        keepDailyDays: keepDaily.trim() === "" ? null : Number(keepDaily),
+      }),
     onSuccess: (next) => {
       setToast({ kind: "ok", msg: t("backup.saved") });
       setCheck(null);
@@ -101,7 +112,10 @@ export function BackupSettings() {
     },
   });
 
-  const dirty = (status?.targetDir ?? "") !== target.trim();
+  const dirty =
+    (status?.targetDir ?? "") !== target.trim() ||
+    String(status?.keepLast ?? "") !== keepLast.trim() ||
+    String(status?.keepDailyDays ?? "") !== keepDaily.trim();
 
   return (
     <div className="">
@@ -134,8 +148,9 @@ export function BackupSettings() {
         </div>
       )}
 
-      {/* Target directory — the admin-chosen destination. */}
+      {/* Config — admin-chosen destination + retention policy. */}
       <div className="card mb-3 p-4">
+        {/* Target directory + its Test probe. */}
         <div className="field">
           <span className="label">{t("backup.targetLabel")}</span>
           <div className="flex flex-wrap items-center gap-2">
@@ -156,17 +171,6 @@ export function BackupSettings() {
             >
               {t("backup.test")}
             </button>
-            <button
-              type="button"
-              className="btn btn-primary btn-sm"
-              disabled={save.isPending || !dirty}
-              onClick={() => {
-                setToast(null);
-                save.mutate();
-              }}
-            >
-              {t("backup.save")}
-            </button>
           </div>
           <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.targetHint")}</span>
           {check && (
@@ -175,6 +179,46 @@ export function BackupSettings() {
             </span>
           )}
         </div>
+
+        {/* Retention — admin-tuned policy (how many backups to keep at the target). */}
+        <div className="mt-4 flex flex-wrap items-start gap-6">
+          <div className="field">
+            <span className="label">{t("backup.keepLastLabel")}</span>
+            <input
+              type="number"
+              min={0}
+              className="input w-28"
+              value={keepLast}
+              onChange={(e) => setKeepLast(e.target.value)}
+            />
+            <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.keepLastHint")}</span>
+          </div>
+          <div className="field">
+            <span className="label">{t("backup.keepDailyLabel")}</span>
+            <input
+              type="number"
+              min={0}
+              className="input w-28"
+              value={keepDaily}
+              onChange={(e) => setKeepDaily(e.target.value)}
+            />
+            <span className="mt-1 text-[0.6875rem] text-term-muted">{t("backup.keepDailyHint")}</span>
+          </div>
+        </div>
+
+        <div className="mt-4 flex items-center gap-3">
+          <button
+            type="button"
+            className="btn btn-primary btn-sm"
+            disabled={save.isPending || !dirty}
+            onClick={() => {
+              setToast(null);
+              save.mutate();
+            }}
+          >
+            {t("backup.save")}
+          </button>
+        </div>
       </div>
 
       <div className="card p-4">
diff --git a/apps/web/src/api.ts b/apps/web/src/api.ts
index 23bee5d..a7e30be 100644
--- a/apps/web/src/api.ts
+++ b/apps/web/src/api.ts
@@ -234,6 +234,9 @@ export interface BackupStatus {
   configured: boolean;
   /** Admin-chosen target directory (null = not set). */
   targetDir: string | null;
+  /** Admin-tuned retention (resolved value: DB or code default). */
+  keepLast: number;
+  keepDailyDays: number;
   /** Whether the env encryption key is present (a missing key is flagged distinctly). */
   keyPresent: boolean;
   running: boolean;
@@ -247,9 +250,16 @@ export async function fetchBackupStatus(): Promise<BackupStatus> {
   return apiFetch("/api/backup/status");
 }
 
-/** Set (or clear, with "") the admin-chosen target directory. Returns the new status. */
-export async function setBackupTarget(targetDir: string | null): Promise<BackupStatus> {
-  return apiFetch("/api/backup/config", { method: "PUT", body: JSON.stringify({ targetDir }) });
+export interface BackupConfigPatch {
+  /** "" clears the target. Omit a field to leave it unchanged; null resets retention to default. */
+  targetDir?: string | null;
+  keepLast?: number | null;
+  keepDailyDays?: number | null;
+}
+
+/** Update backup config (target dir and/or retention). Returns the new status. */
+export async function setBackupConfig(patch: BackupConfigPatch): Promise<BackupStatus> {
+  return apiFetch("/api/backup/config", { method: "PUT", body: JSON.stringify(patch) });
 }
 
 export interface TargetCheck {
diff --git a/apps/web/src/lib/i18n/en.ts b/apps/web/src/lib/i18n/en.ts
index 8b6d787..d3e2e02 100644
--- a/apps/web/src/lib/i18n/en.ts
+++ b/apps/web/src/lib/i18n/en.ts
@@ -865,6 +865,10 @@ export const en: Catalog = {
     testNotDir: "The path is not a directory.",
     testNotWritable: "The directory is not writable.",
     keyMissing: "The encryption key (BACKUP_KEY) is missing on the server — set it to enable backups.",
+    keepLastLabel: "Keep last",
+    keepLastHint: "How many of the newest backups to always keep.",
+    keepDailyLabel: "Keep daily (days)",
+    keepDailyHint: "Beyond those, keep one backup per day for this many days.",
   },
   pay: {
     ticket: "Ticket",
diff --git a/apps/web/src/lib/i18n/sq.ts b/apps/web/src/lib/i18n/sq.ts
index f7edda0..2b78256 100644
--- a/apps/web/src/lib/i18n/sq.ts
+++ b/apps/web/src/lib/i18n/sq.ts
@@ -881,6 +881,10 @@ export const sq = {
     testNotDir: "Rruga nuk është një dosje.",
     testNotWritable: "Dosja nuk është e shkruajtshme.",
     keyMissing: "Çelësi i enkriptimit (BACKUP_KEY) mungon në server — caktoje që kopja të aktivizohet.",
+    keepLastLabel: "Mbaj kopjet e fundit",
+    keepLastHint: "Numri i kopjeve më të reja që mbahen gjithmonë.",
+    keepDailyLabel: "Mbaj ditore (ditë)",
+    keepDailyHint: "Përtej atyre, mbaj një kopje për ditë për kaq ditë.",
   },
   pay: {
     ticket: "Bileta",
diff --git a/komodo/.env.komodo.example b/komodo/.env.komodo.example
index c0b6105..ffa168e 100644
--- a/komodo/.env.komodo.example
+++ b/komodo/.env.komodo.example
@@ -29,6 +29,18 @@ EVENT_SIGNING_KEY=[[booth_<name>_event_signing_key]]
 # without =0 the auth cookie never sends and operators CANNOT log in. Set 1 only behind TLS.
 COOKIE_SECURE=0
 
+# ════════════════════════════════════════════════════════════════════════════
+# BACKUP (encrypted on-site DB backup — see wiki/concepts/backup-recovery.md)
+# ════════════════════════════════════════════════════════════════════════════
+# Dedicated backup-ENCRYPTION key. SEPARATE from EVENT_SIGNING_KEY (independent rotation;
+# backups travel to the target, the signing key must not). Per booth + unique. openssl rand
+# -hex 32. ESCROW it offsite alongside EVENT_SIGNING_KEY — disaster recovery needs BOTH, and
+# neither is ever stored inside the backup it unlocks. Backups stay OFF until this key is set
+# AND the admin picks a target directory in the UI. The key is the ONLY backup env var — the
+# target directory and retention (keep-last / keep-daily) are admin-chosen in the UI (Setup →
+# Backup) and stored in the DB, so changing them needs no redeploy.
+BACKUP_KEY=[[booth_<name>_backup_key]]
+
 # ════════════════════════════════════════════════════════════════════════════
 # COMMONLY SET (have defaults, but you usually want these explicit on a booth)
 # ════════════════════════════════════════════════════════════════════════════
@@ -103,5 +115,6 @@ WS_ALLOWED_ORIGINS=
 # ════════════════════════════════════════════════════════════════════════════
 #   JWT_SECRET            -> [[booth_<name>_jwt_secret]]            (login)
 #   EVENT_SIGNING_KEY     -> [[booth_<name>_event_signing_key]]    (ledger signing — fraud root)
+#   BACKUP_KEY            -> [[booth_<name>_backup_key]]           (backup encryption — escrow offsite)
 #   periphery passkey     -> [[periphery_passkey_booth_<name>]]    (agent onboarding)
 #   registry account      -> [[gitea_registry_account]]            (image pull)
diff --git a/komodo/resources.toml b/komodo/resources.toml
index 0e08091..99594a7 100644
--- a/komodo/resources.toml
+++ b/komodo/resources.toml
@@ -15,7 +15,8 @@
 #
 # Secrets ([[park_buzi_jwt_secret]] etc.) are REFERENCES to Komodo Core's secret store —
 # per-booth + unique, never inlined here (this file is in git). JWT_SECRET gates login;
-# EVENT_SIGNING_KEY signs the append-only anti-fraud ledger.
+# EVENT_SIGNING_KEY signs the append-only anti-fraud ledger; BACKUP_KEY encrypts on-site DB
+# backups (separate from the signing key; escrow it offsite — recovery needs both).
 #
 # Deploys are MANUAL + PINNED in spirit: bump TAG to an immutable dev-<sha> before a
 # production booth goes live (TAG=dev here is the moving tag, fine while staging). NO
@@ -48,4 +49,5 @@ VISION_ENABLED=1
 WS_ALLOWED_ORIGINS=
 JWT_SECRET=[[park_buzi_jwt_secret]]
 EVENT_SIGNING_KEY=[[park_buzi_event_signing_key]]
+BACKUP_KEY=[[park_buzi_backup_key]]
 """
diff --git a/packages/db/drizzle/0017_backup_retention.sql b/packages/db/drizzle/0017_backup_retention.sql
new file mode 100644
index 0000000..553b285
--- /dev/null
+++ b/packages/db/drizzle/0017_backup_retention.sql
@@ -0,0 +1,6 @@
+-- Backup retention is OPERATIONAL POLICY the on-site admin tunes from the Backup screen, not a
+-- server env var requiring a redeploy. Two additive, nullable columns on the single-row config;
+-- null = fall back to the code default (keepLast 7, keepDailyDays 30). The backup ENGINE stays
+-- parameterized; this just moves the source of truth env → DB. See wiki/concepts/backup-recovery.md.
+ALTER TABLE `site_config` ADD `backup_keep_last` integer;--> statement-breakpoint
+ALTER TABLE `site_config` ADD `backup_keep_daily_days` integer;
diff --git a/packages/db/drizzle/meta/_journal.json b/packages/db/drizzle/meta/_journal.json
index a5b14a7..cc52057 100644
--- a/packages/db/drizzle/meta/_journal.json
+++ b/packages/db/drizzle/meta/_journal.json
@@ -120,6 +120,13 @@
       "when": 1781885900000,
       "tag": "0016_backup_target_dir",
       "breakpoints": true
+    },
+    {
+      "idx": 17,
+      "version": "6",
+      "when": 1781886000000,
+      "tag": "0017_backup_retention",
+      "breakpoints": true
     }
   ]
 }
\ No newline at end of file
diff --git a/packages/db/src/schema.ts b/packages/db/src/schema.ts
index eaa5c07..dd7124b 100644
--- a/packages/db/src/schema.ts
+++ b/packages/db/src/schema.ts
@@ -269,6 +269,11 @@ export const siteConfig = sqliteTable("site_config", {
    *  screen; the encryption key (BACKUP_KEY) stays an env/Komodo secret and is NEVER stored
    *  here (a key must not live in the DB it backs up). See wiki/concepts/backup-recovery.md. */
   backupTargetDir: text("backup_target_dir"),
+  /** Backup retention (admin-tunable policy, not env). Keep this many newest backups always.
+   *  null ⇒ code default (7). See wiki/concepts/backup-recovery.md. */
+  backupKeepLast: integer("backup_keep_last"),
+  /** Beyond keepLast, keep one backup per day for this many days. null ⇒ code default (30). */
+  backupKeepDailyDays: integer("backup_keep_daily_days"),
   updatedAt: text("updated_at")
     .notNull()
     .default(sql`(current_timestamp)`),
diff --git a/wiki/concepts/backup-recovery.md b/wiki/concepts/backup-recovery.md
index bab7906..645dc29 100644
--- a/wiki/concepts/backup-recovery.md
+++ b/wiki/concepts/backup-recovery.md
@@ -133,12 +133,15 @@ timer + the manual route**. What landed:
   **keep-last-N + one-per-day-within-N-days** (`pruneOldBackups`). Tested: round-trip decrypts to a
   **byte-identical, queryable DB**; a flipped byte or wrong key **fails GCM auth**; short key rejected;
   scratch plaintext always removed.
-- **`backup-service.ts`** — the **target directory is admin-chosen** (`site_config.backup_target_dir`,
-  migration 0016) and read **fresh each run**, so changing it in the UI takes effect with no restart.
-  Only the **encryption key stays an env/Komodo secret** (`BACKUP_KEY`) — a key must never live in the
-  DB it backs up. Retention knobs (`BACKUP_KEEP_LAST`, `BACKUP_KEEP_DAILY_DAYS`) stay env. The service
-  **serializes** concurrent runs (single in-flight guard) and records last-success / last-error;
-  `status()` exposes `targetDir` + `keyPresent` so the UI distinguishes "no target" from "no key".
+- **`backup-service.ts`** — the **target directory AND retention are admin-chosen** in the UI
+  (`site_config.backup_target_dir`, migration 0016; `backup_keep_last` + `backup_keep_daily_days`,
+  migration 0017) and read **fresh each run**, so changing them takes effect with no restart. Retention
+  columns are nullable → fall back to the code default (keep-last 7, keep-daily 30) per field. The
+  **encryption key is the ONLY backup env/Komodo secret** (`BACKUP_KEY`) — a key must never live in the
+  DB it backs up; target+retention are operational policy, not secrets. The service **serializes**
+  concurrent runs (single in-flight guard) and records last-success / last-error; `status()` exposes
+  `targetDir`, `keepLast`, `keepDailyDays` + `keyPresent` so the UI distinguishes "no target" from
+  "no key".
 - **`routes/backup.ts`** — `GET /api/backup/status` (`backup:read`); `PUT /api/backup/config` to set/
   clear the target (`backup:update`); `POST /api/backup/test` to probe a candidate path server-side —
   exists / is-a-dir / writable (`backup:update`); `POST /api/backup/run` (`backup:create`), a clean
@@ -146,9 +149,12 @@ timer + the manual route**. What landed:
   (`backup:read/update/create`) in `@parking/shared`. **No restore route** — out-of-band by design.
 - **`apps/web/src/BackupSettings.tsx`** — a Setup → **Backup** tab (gated `backup:read`): an editable
   **target-path field** with a **Test target** probe (localized ok/missing/not-a-dir/not-writable),
-  **Save**, the status panel (config state, last-run size/pruned/error, a distinct amber **missing
-  BACKUP_KEY** warning), a **Back up now** button, and the restore-is-out-of-band note. Full i18n
-  (sq + en).
+  **retention fields** (keep-last / keep-daily-days), one **Save**, the status panel (config state,
+  last-run size/pruned/error, a distinct amber **missing BACKUP_KEY** warning), a **Back up now**
+  button, and the restore-is-out-of-band note. Full i18n (sq + en).
+- **Komodo wiring.** `BACKUP_KEY` is a **per-booth Komodo secret** (`[[park_buzi_backup_key]]` in
+  `komodo/resources.toml`; documented in `komodo/.env.komodo.example`), escrowed offsite alongside
+  `EVENT_SIGNING_KEY`. It is the *only* backup env var — target + retention are in the DB.
 - **`server.ts`** — an **unref'd daily timer** (`backupService.runScheduled`), a **no-op until
   configured**, and **deliberately NOT run at startup** (a just-power-cut booth shouldn't write to a
   possibly-unmounted disk; the daily cadence + the manual button cover it).
diff --git a/wiki/log.md b/wiki/log.md
index 51c4c77..3a1cf7d 100644
--- a/wiki/log.md
+++ b/wiki/log.md
@@ -1948,3 +1948,17 @@ status panel (distinct amber "BACKUP_KEY missing" warning) + Back-up-now + resto
 i18n sq+en; nav.backup. Verified live with Playwright: typed path → Test "writable" → Save persisted →
 status reflects it + key-missing warning shown. build/lint/test green (whole monorepo). Updated
 [[backup-recovery]] as-built + [[open-questions]] #5.
+
+## [2026-06-29] feat | Backup retention admin-tunable + BACKUP_KEY wired into Komodo
+Same reasoning as the target dir: backup retention is operational policy the on-site admin tunes, not a
+server env var requiring a redeploy. Moved BACKUP_KEEP_LAST/BACKUP_KEEP_DAILY_DAYS env → site_config
+(migration 0017: backup_keep_last, backup_keep_daily_days, both nullable → code default 7/30 per field).
+BackupService reads retention fresh each run; status() now exposes keepLast/keepDailyDays. PUT
+/api/backup/config extended to accept keepLast/keepDailyDays (non-negative int or null=reset-to-default,
+400 on negative). UI: two retention number fields on the Backup config card, one Save covers target +
+retention; i18n sq+en. DEFAULT_BACKUP_RETENTION is now a pure code default (env reads dropped). Komodo:
+BACKUP_KEY wired as a per-booth secret ([[park_buzi_backup_key]] in komodo/resources.toml; documented in
+komodo/.env.komodo.example as the ONLY backup env var — target+retention are UI/DB). Server .env.example
+trimmed to just BACKUP_KEY. build/lint/test green (218 server tests, incl. retention persist/reset/negative
++ updated status shape). NOTE: dev API process was down after this round (live process, not code) — verified
+via the full test harness, not a live click-through this time. Updated [[backup-recovery]] as-built.