diff --git a/README.md b/README.md
index b5a06a5b..24a042d6 100644
--- a/README.md
+++ b/README.md
@@ -100,9 +100,11 @@ latest styles.
   - Central place for instance-specific values like the Super Admin npub and the
     default whitelist-only mode setting. Update the documented exports here when
     preparing a new deployment.
-  - Tune `PLATFORM_FEE_PERCENT` (0–100) to keep a percentage of Lightning tips
-    and set `PLATFORM_LUD16_OVERRIDE` when you need a deployment-wide fallback
-    Lightning address. Leave the fee at `0` to pass through every satoshi.
+  - Tune `PLATFORM_FEE_PERCENT` (0–100) to keep a percentage of Lightning tips.
+    When the fee is positive, BitVid routes the platform’s split to
+    `PLATFORM_LUD16_OVERRIDE`, so set it to the Lightning address that should
+    receive the sats (or publish a `lud16` on the Super Admin profile). Leave
+    the fee at `0` to pass through every satoshi.
   - Populate `DEFAULT_RELAY_URLS_OVERRIDE` with WSS URLs to replace the bundled
     relay bootstrap list. Keep it empty to stick with the upstream defaults.
 - **`config.js`**:
diff --git a/config/instance-config.js b/config/instance-config.js
index eec179e2..7c565979 100644
--- a/config/instance-config.js
+++ b/config/instance-config.js
@@ -38,8 +38,11 @@ export const PLATFORM_FEE_PERCENT = 0;
  * Lightning address to fall back to when authors omit their own `lud16`.
  *
  * Supply a string like `"tips@example.com"` to force a deployment-wide
- * fallback Lightning address, or leave the value as `null` to respect the
- * creator’s configured profile metadata.
+ * fallback Lightning address. When `PLATFORM_FEE_PERCENT` is greater than 0,
+ * this override also acts as the Lightning target for the platform’s split.
+ * Leave the value as `null` to respect the creator’s metadata and rely on the
+ * Super Admin profile publishing a `lud16` so BitVid still knows where to route
+ * fees when they are enabled.
  */
 export const PLATFORM_LUD16_OVERRIDE = null;
 
diff --git a/config/validate-config.js b/config/validate-config.js
index fb9b78b3..8d06219e 100644
--- a/config/validate-config.js
+++ b/config/validate-config.js
@@ -3,16 +3,20 @@
 // Runtime validation helpers for instance-level configuration
 // -----------------------------------------------------------------------------
 
-import { ADMIN_SUPER_NPUB, PLATFORM_FEE_PERCENT } from "./instance-config.js";
+import {
+  ADMIN_SUPER_NPUB,
+  PLATFORM_FEE_PERCENT,
+  PLATFORM_LUD16_OVERRIDE,
+} from "./instance-config.js";
 
-function assertSuperAdminConfigured() {
-  if (typeof ADMIN_SUPER_NPUB !== "string") {
+function assertSuperAdminConfigured(value) {
+  if (typeof value !== "string") {
     throw new Error(
       "ADMIN_SUPER_NPUB must be a string exported from config/instance-config.js."
     );
   }
 
-  const trimmed = ADMIN_SUPER_NPUB.trim();
+  const trimmed = value.trim();
   if (!trimmed) {
     throw new Error(
       "ADMIN_SUPER_NPUB is required. Populate it with the Super Admin npub in config/instance-config.js."
@@ -24,26 +28,58 @@ function assertSuperAdminConfigured() {
       "ADMIN_SUPER_NPUB should be a bech32 npub (e.g., starting with 'npub')."
     );
   }
+  return trimmed;
 }
 
-function assertPlatformFeeInRange() {
-  const value =
-    typeof PLATFORM_FEE_PERCENT === "number"
-      ? PLATFORM_FEE_PERCENT
-      : Number.parseFloat(PLATFORM_FEE_PERCENT);
+function assertPlatformFeeInRange(value) {
+  const numericValue =
+    typeof value === "number" ? value : Number.parseFloat(value);
 
-  if (!Number.isFinite(value)) {
+  if (!Number.isFinite(numericValue)) {
     throw new Error(
       "PLATFORM_FEE_PERCENT must be a finite number between 0 and 100."
     );
   }
 
-  if (value < 0 || value > 100) {
+  if (numericValue < 0 || numericValue > 100) {
     throw new Error("PLATFORM_FEE_PERCENT must be between 0 and 100 inclusive.");
   }
+
+  return numericValue;
 }
 
-export function validateInstanceConfig() {
-  assertSuperAdminConfigured();
-  assertPlatformFeeInRange();
+function getPlatformLud16Override(value) {
+  if (typeof value !== "string") {
+    return "";
+  }
+
+  return value.trim();
+}
+
+function resolveConfig(overrides = {}) {
+  return {
+    adminSuperNpub:
+      overrides.ADMIN_SUPER_NPUB ?? ADMIN_SUPER_NPUB,
+    platformFeePercent:
+      overrides.PLATFORM_FEE_PERCENT ?? PLATFORM_FEE_PERCENT,
+    platformLud16Override:
+      overrides.PLATFORM_LUD16_OVERRIDE ?? PLATFORM_LUD16_OVERRIDE,
+  };
+}
+
+export function validateInstanceConfig(overrides) {
+  const config = resolveConfig(overrides);
+  assertSuperAdminConfigured(config.adminSuperNpub);
+  const platformFeePercent = assertPlatformFeeInRange(
+    config.platformFeePercent
+  );
+  const trimmedOverride = getPlatformLud16Override(
+    config.platformLud16Override
+  );
+
+  if (platformFeePercent > 0 && !trimmedOverride) {
+    throw new Error(
+      "PLATFORM_FEE_PERCENT is positive but PLATFORM_LUD16_OVERRIDE is empty. Set PLATFORM_LUD16_OVERRIDE to the Lightning address that should receive the platform's split, or publish a lud16 value on the Super Admin profile so BitVid can route platform fees."
+    );
+  }
 }
diff --git a/tests/validate-config.test.mjs b/tests/validate-config.test.mjs
new file mode 100644
index 00000000..0244a58e
--- /dev/null
+++ b/tests/validate-config.test.mjs
@@ -0,0 +1,21 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+import { validateInstanceConfig } from "../config/validate-config.js";
+
+test(
+  "validateInstanceConfig throws when platform fee is positive without a platform override",
+  () => {
+    const overrides = {
+      ADMIN_SUPER_NPUB:
+        "npub1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq",
+      PLATFORM_FEE_PERCENT: 5,
+      PLATFORM_LUD16_OVERRIDE: "   ",
+    };
+
+    assert.throws(() => validateInstanceConfig(overrides), {
+      message:
+        "PLATFORM_FEE_PERCENT is positive but PLATFORM_LUD16_OVERRIDE is empty. Set PLATFORM_LUD16_OVERRIDE to the Lightning address that should receive the platform's split, or publish a lud16 value on the Super Admin profile so BitVid can route platform fees.",
+    });
+  }
+);