diff --git a/src/components/insights/metric-range-delta.tsx b/src/components/insights/metric-range-delta.tsx
index 070e71eec..477ce1aea 100644
--- a/src/components/insights/metric-range-delta.tsx
+++ b/src/components/insights/metric-range-delta.tsx
@@ -10,7 +10,7 @@ import {
   type TrendDirectionSentiment,
 } from "@/lib/insights/trend-sentiment";
 import type { AnalyticsRangeData } from "@/hooks/use-analytics-range";
-import type { AnalyticsRange } from "@/lib/analytics/range-delta";
+import type { AnalyticsRange } from "@/lib/analytics/range-shared";
 
 /**
  * v1.9.0 — period-over-period delta caption beside the time-range pills.
diff --git a/src/components/insights/time-range-pills.tsx b/src/components/insights/time-range-pills.tsx
index 32630c9ff..06015d9f2 100644
--- a/src/components/insights/time-range-pills.tsx
+++ b/src/components/insights/time-range-pills.tsx
@@ -7,7 +7,7 @@ import { cn } from "@/lib/utils";
 import {
   ANALYTICS_RANGES,
   type AnalyticsRange,
-} from "@/lib/analytics/range-delta";
+} from "@/lib/analytics/range-shared";
 
 /**
  * v1.9.0 — `7d / 30d / 90d / 1y` segmented control for the Insights metric
diff --git a/src/hooks/use-analytics-range.ts b/src/hooks/use-analytics-range.ts
index dfb38bc3d..93ac680c0 100644
--- a/src/hooks/use-analytics-range.ts
+++ b/src/hooks/use-analytics-range.ts
@@ -4,7 +4,7 @@ import { useQuery } from "@tanstack/react-query";
 
 import { useAuth } from "@/hooks/use-auth";
 import { queryKeys } from "@/lib/query-keys";
-import type { AnalyticsRange } from "@/lib/analytics/range-delta";
+import type { AnalyticsRange } from "@/lib/analytics/range-shared";
 
 /**
  * v1.9.0 — client reader for the single-metric period-over-period range
diff --git a/src/hooks/use-insights-layout-prefs.ts b/src/hooks/use-insights-layout-prefs.ts
index c863d24b1..bf347e758 100644
--- a/src/hooks/use-insights-layout-prefs.ts
+++ b/src/hooks/use-insights-layout-prefs.ts
@@ -12,7 +12,7 @@ import {
 import {
   ANALYTICS_RANGES,
   type AnalyticsRange,
-} from "@/lib/analytics/range-delta";
+} from "@/lib/analytics/range-shared";
 
 const RANGE_STORAGE_KEY = "healthlog.insights.range";
 const DEFAULT_RANGE: AnalyticsRange = "30d";
diff --git a/src/lib/analytics/range-delta.ts b/src/lib/analytics/range-delta.ts
index 2132e4778..88d675c53 100644
--- a/src/lib/analytics/range-delta.ts
+++ b/src/lib/analytics/range-delta.ts
@@ -33,53 +33,27 @@ import {
   readBestGranularityRollups,
   type RollupBucketRow,
 } from "@/lib/rollups/measurement-read-wmy";
+import {
+  ANALYTICS_RANGES,
+  rangeWindowDays,
+  type AnalyticsRange,
+  type RangeDeltaResult,
+  type WindowAggregate,
+} from "@/lib/analytics/range-shared";
 
-const DAY_MS = 24 * 60 * 60 * 1000;
-
-/** The user-selectable ranges. */
-export const ANALYTICS_RANGES = ["7d", "30d", "90d", "1y"] as const;
-export type AnalyticsRange = (typeof ANALYTICS_RANGES)[number];
-
-/** Trailing-window length, in days, for each range. */
-const RANGE_WINDOW_DAYS: Record<AnalyticsRange, number> = {
-  "7d": 7,
-  "30d": 30,
-  "90d": 90,
-  "1y": 365,
+// The range constants + result shapes live in the client-safe
+// `range-shared` module so the insights client bundle never pulls the
+// server-only rollup readers (and `pg`) through a range import. Re-exported
+// here so existing server-side callers keep importing from `range-delta`.
+export {
+  ANALYTICS_RANGES,
+  rangeWindowDays,
+  type AnalyticsRange,
+  type RangeDeltaResult,
+  type WindowAggregate,
 };
 
-export function rangeWindowDays(range: AnalyticsRange): number {
-  return RANGE_WINDOW_DAYS[range];
-}
-
-/** A composed window aggregate. `mean`/etc. are null when the window is empty. */
-export interface WindowAggregate {
-  count: number;
-  min: number | null;
-  max: number | null;
-  mean: number | null;
-  sum: number | null;
-}
-
-export interface RangeDeltaResult {
-  range: AnalyticsRange;
-  windowDays: number;
-  /** The granularity the underlying rollup read resolved against. */
-  granularity: string;
-  current: WindowAggregate;
-  previous: WindowAggregate;
-  /**
-   * `current.mean - previous.mean`, or null when either window has no mean
-   * (no data in the current or prior window) — never a misleading 0.
-   */
-  delta: number | null;
-  /**
-   * `delta / previous.mean` as a fraction (0.03 = +3 %), or null when the
-   * prior window has no mean / a zero mean (no divide-by-zero, no misleading
-   * 0 %). The client renders "no prior-period data" in that case.
-   */
-  deltaPct: number | null;
-}
+const DAY_MS = 24 * 60 * 60 * 1000;
 
 /**
  * Slice the resolved buckets into the current half (`[now-N, now)`) and the
diff --git a/src/lib/analytics/range-shared.ts b/src/lib/analytics/range-shared.ts
new file mode 100644
index 000000000..1aa355c91
--- /dev/null
+++ b/src/lib/analytics/range-shared.ts
@@ -0,0 +1,58 @@
+/**
+ * v1.9.0 — client-safe range constants and types for the Insights metric
+ * pages.
+ *
+ * The user-selectable range list, its type, the per-range window length, and
+ * the period-over-period result shapes are shared between the client (the
+ * pills, the delta caption, the range hook, the layout-prefs hook) and the
+ * server (`/api/analytics/range` + `range-delta.ts`). This module imports
+ * NOTHING server-side — no rollup readers, no `db`, no Prisma client — so the
+ * client bundle never transitively pulls `pg` (dns/fs/net/tls) through a range
+ * import. The server-only window-composition logic lives in `range-delta.ts`,
+ * which re-exports these names for its own callers.
+ */
+
+/** The user-selectable ranges. */
+export const ANALYTICS_RANGES = ["7d", "30d", "90d", "1y"] as const;
+export type AnalyticsRange = (typeof ANALYTICS_RANGES)[number];
+
+/** Trailing-window length, in days, for each range. */
+const RANGE_WINDOW_DAYS: Record<AnalyticsRange, number> = {
+  "7d": 7,
+  "30d": 30,
+  "90d": 90,
+  "1y": 365,
+};
+
+export function rangeWindowDays(range: AnalyticsRange): number {
+  return RANGE_WINDOW_DAYS[range];
+}
+
+/** A composed window aggregate. `mean`/etc. are null when the window is empty. */
+export interface WindowAggregate {
+  count: number;
+  min: number | null;
+  max: number | null;
+  mean: number | null;
+  sum: number | null;
+}
+
+export interface RangeDeltaResult {
+  range: AnalyticsRange;
+  windowDays: number;
+  /** The granularity the underlying rollup read resolved against. */
+  granularity: string;
+  current: WindowAggregate;
+  previous: WindowAggregate;
+  /**
+   * `current.mean - previous.mean`, or null when either window has no mean
+   * (no data in the current or prior window) — never a misleading 0.
+   */
+  delta: number | null;
+  /**
+   * `delta / previous.mean` as a fraction (0.03 = +3 %), or null when the
+   * prior window has no mean / a zero mean (no divide-by-zero, no misleading
+   * 0 %). The client renders "no prior-period data" in that case.
+   */
+  deltaPct: number | null;
+}