diff --git a/dev-docs/bidders/rediads.md b/dev-docs/bidders/rediads.md
index 180b8a9938..35abcb8a17 100644
--- a/dev-docs/bidders/rediads.md
+++ b/dev-docs/bidders/rediads.md
@@ -16,24 +16,26 @@ safeframes_ok: false
 deals_supported: false
 floors_supported: true
 fpd_supported: true
+userIds: rediadsId
 ortb_blocking_supported: partial
 privacy_sandbox: no
 multiformat_supported: will-bid-on-one
 sidebarType: 1
 ---
 
-### Bid Params
+## Bid Params
 
 {: .table .table-bordered .table-striped }
-| Name         | Scope    | Description                                                                 | Example              | Type           |
-|--------------|----------|-----------------------------------------------------------------------------|----------------------|----------------|
-| account_id   | required | Account ID generated on the Rediads Platform.                               | '123xyz'             | string       |
-| endpoint     | optional | Only to be used if RediAds team provides you with one.                      | 'bidding2'        | string       |
-| slot         | optional | Unique identifier for the ad slot generated on the platform.                | '54321'              | string       |
+
+| Name       | Scope    | Description                                                  | Example      | Type   |
+| ---------- | -------- | ------------------------------------------------------------ | ------------ | ------ |
+| account_id | required | Account ID generated on the Rediads Platform.                | `'123xyz'`   | string |
+| endpoint   | optional | Only to be used if RediAds team provides you with one.       | `'bidding2'` | string |
+| slot       | optional | Unique identifier for the ad slot generated on the platform. | `'54321'`    | string |
 
 ---
 
-### Enabling Test Bids
+## Enabling Test Bids
 
 To enable test bids for the Rediads Bidder Adapter, append rediads-test-bids to the hash of the page URL.
 
@@ -46,9 +48,9 @@ This will activate test bids for debugging and validation purposes.
 
 ---
 
-### AdUnit Examples
+## AdUnit Examples
 
-#### AdUnit Format for Banner
+### AdUnit Format for Banner
 
 ```javascript
 var adUnits = [
@@ -72,7 +74,7 @@ var adUnits = [
 ];
 ```
 
-### First Party Data Support
+## First Party Data Support
 The following fields are supported for First Party Data (FPD):
 
 - `ortb2.site.*`
@@ -81,3 +83,11 @@ The following fields are supported for First Party Data (FPD):
 - `ortb2.devices.locations parameters`
 
 For additional implementation or support, contact us at <support@rediads.com>.
+
+## User ID Support
+
+The Rediads bidder supports the `rediadsId` user ID submodule. To build both together:
+
+```bash
+gulp build --modules=rediadsBidAdapter,userId,rediadsIdSystem
+```
diff --git a/dev-docs/modules/userid-submodules/rediads.md b/dev-docs/modules/userid-submodules/rediads.md
new file mode 100644
index 0000000000..d2d0775a15
--- /dev/null
+++ b/dev-docs/modules/userid-submodules/rediads.md
@@ -0,0 +1,125 @@
+---
+layout: userid
+title: Rediads ID
+description: Rediads User ID sub-module
+useridmodule: rediadsIdSystem
+bidRequestUserId: rediadsId
+eidsource: rediads.com
+example: '"ruid_7b9c1d3f-1e2b-4e7b-9e5a-acde12345678"'
+---
+
+## Overview
+
+The Rediads User ID submodule generates a first-party browser identifier for publisher-side identity and makes it available to Prebid bidders through both `bidRequest.userId.rediadsId` and `bidRequest.userIdAsEids`.
+
+This submodule is implemented as a Prebid User ID module and uses Prebid-managed storage.
+
+## Registration
+
+For setup information, contact [support@rediads.com](mailto:support@rediads.com).
+
+## Installation
+
+Build Prebid.js with the User ID core module, the Rediads ID submodule, and optionally the Rediads bidder:
+
+```bash
+gulp build --modules=rediadsBidAdapter,userId,rediadsIdSystem
+```
+
+If you only need the user ID module, you can omit `rediadsBidAdapter`:
+
+```bash
+gulp build --modules=userId,rediadsIdSystem
+```
+
+## Configuration
+
+```javascript
+pbjs.setConfig({
+  userSync: {
+    userIds: [{
+      name: 'rediadsId',
+      params: {
+        source: 'rediads.com'
+      },
+      storage: {
+        type: 'html5',
+        name: 'rediads_id',
+        expires: 30,
+        refreshInSeconds: 3600
+      }
+    }]
+  }
+});
+```
+
+## Parameters
+
+{: .table .table-bordered .table-striped }
+
+| Param under `userSync.userIds[]` | Scope | Type | Description | Example |
+| --- | --- | --- | --- | --- |
+| `name` | Required | String | Module identifier. Must be `"rediadsId"`. | `"rediadsId"` |
+| `params` | Optional | Object | Rediads-specific configuration. | |
+| `params.source` | Optional | String | EID source to emit. Defaults to `"rediads.com"`. | `"rediads.com"` |
+| `storage` | Recommended | Object | Prebid-managed storage configuration. | |
+| `storage.type` | Recommended | String | Storage type. Use `"html5"`, `"cookie"`, or `"cookie&html5"` as needed. | `"html5"` |
+| `storage.name` | Recommended | String | Storage key name. | `"rediads_id"` |
+| `storage.expires` | Optional | Number | Lifetime of the stored ID in days. Defaults to `30`. | `30` |
+| `storage.refreshInSeconds` | Optional | Number | Refresh interval in seconds. Defaults to `3600`. | `3600` |
+
+## Privacy Handling
+
+The Rediads ID submodule follows the standard Prebid User ID privacy flow.
+
+- If COPPA applies, the module does not create or return an ID.
+- If GDPR applies without a valid consent string and Purpose 1 consent, the module does not create or return an ID.
+- If US Privacy or GPP opt-out signals restrict sharing, the module may still retain its local ID state but does not emit EIDs for bidder sharing.
+
+The module uses Prebid's vendorless TCF marker so purpose-level enforcement applies without requiring a separate vendor registration in the module config.
+
+## Bid Request Output
+
+When available, the Rediads ID is exposed on the bid request as:
+
+```javascript
+bidRequest.userId.rediadsId
+```
+
+Example:
+
+```json
+{
+  "uid": "ruid_7b9c1d3f-1e2b-4e7b-9e5a-acde12345678",
+  "source": "rediads.com",
+  "atype": 1,
+  "ext": {
+    "canShare": true
+  }
+}
+```
+
+## EID Output
+
+When sharing is permitted, the module contributes the following EID:
+
+```json
+{
+  "source": "rediads.com",
+  "uids": [{
+    "id": "ruid_7b9c1d3f-1e2b-4e7b-9e5a-acde12345678",
+    "atype": 1
+  }]
+}
+```
+
+## Testing
+
+After building Prebid.js with `userId` and `rediadsIdSystem`, you can verify the module with:
+
+```javascript
+pbjs.getUserIds()
+pbjs.getUserIdsAsEids()
+```
+
+You should see `rediadsId` in `getUserIds()` and a `rediads.com` entry in `getUserIdsAsEids()` when privacy settings allow sharing.