diff --git a/components/schemas/UserSettingObject.yaml b/components/schemas/UserSettingObject.yaml
new file mode 100644
index 0000000..8bbdff7
--- /dev/null
+++ b/components/schemas/UserSettingObject.yaml
@@ -0,0 +1,21 @@
+type: object
+description: |
+  User settings as flattened key-value pairs.
+  - Setting values are returned with uppercase setting names.
+  - Each setting has a corresponding `{settingName}_lastUpdated` field containing an epoch timestamp.
+  - Setting values are strings, timestamp fields are integers (epoch seconds).
+propertyNames:
+  pattern: '^(?!.*_lastUpdated_lastUpdated$)(?!.*(?:^|_)[A-F0-9]{16,}(?:_|_lastUpdated$|$))(?!.*(?:^|_)\d{8,}(?:_|_lastUpdated$|$))[A-Z][A-Z0-9]*(?:_[A-Z0-9]+)+(?:_lastUpdated)?$'
+patternProperties:
+  '^(?!.*_lastUpdated$).+$':
+    type: string
+    maxLength: 65535
+    description: Setting value
+  '^.+_lastUpdated$':
+    type: integer
+    format: int64
+    description: Epoch timestamp in seconds for when the setting was last updated
+additionalProperties: false
+example:
+  UNIT_TEMPERATURE: 'C'
+  UNIT_TEMPERATURE_lastUpdated: 1773306016
diff --git a/userapi/openapi.yaml b/userapi/openapi.yaml
index a6e7298..e52d5cb 100644
--- a/userapi/openapi.yaml
+++ b/userapi/openapi.yaml
@@ -34,7 +34,8 @@ tags:
     description: Sensor sharing and unsharing
   - name: Subscription
     description: User subscription management
-
+  - name: User-Settings
+    description: User settings management
 
 paths:
   /air_firmwareupdate:
@@ -43,7 +44,7 @@ paths:
     $ref: './alerts.yaml'
   /push-register:
     $ref: './push-register.yaml'
-  /register: 
+  /register:
     $ref: './register.yaml'
   /sensor-settings:
     $ref: './sensor-settings.yaml'
@@ -57,11 +58,12 @@ paths:
     $ref: './share.yaml'
   /subscription:
     $ref: './subscription.yaml'
+  /settings:
+    $ref: './user-settings.yaml'
   /unshare:
     $ref: './unshare.yaml'
-  /verify: 
+  /verify:
     $ref: './verify.yaml'
-  
 
 components:
   securitySchemes:
diff --git a/userapi/user-settings.yaml b/userapi/user-settings.yaml
new file mode 100644
index 0000000..8c21922
--- /dev/null
+++ b/userapi/user-settings.yaml
@@ -0,0 +1,153 @@
+post:
+  summary: Configure a user setting
+  description: Creates or updates a setting for the authenticated user.
+  operationId: setUserSetting
+  tags:
+    - User-Settings
+  security:
+    - bearerAuth: []
+  requestBody:
+    required: true
+    content:
+      application/json:
+        schema:
+          type: object
+          required:
+            - name
+            - value
+          additionalProperties: false
+          properties:
+            name:
+              type: string
+              description: User setting name in snake case, for example `UNIT_TEMPERATURE`, `profile_language_code`, or `settings_123`. Names are stored in uppercase.
+              maxLength: 80
+              pattern: '^(?!.*_[Ll][Aa][Ss][Tt][Uu][Pp][Dd][Aa][Tt][Ee][Dd]$)(?!.*(?:^|_)[A-Fa-f0-9]{16,}(?:_|$))(?!.*(?:^|_)\d{8,}(?:_|$))[A-Za-z][A-Za-z0-9]*(?:_[A-Za-z0-9]+)+$'
+            value:
+              type: string
+              description: User setting value.
+              maxLength: 65535
+            timestamp:
+              type: integer
+              format: int64
+              description: Optional epoch timestamp for the setting. If missing, it is assumed to be the current time.
+        examples:
+          basic:
+            value:
+              name: 'PROFILE_LANGUAGE_CODE'
+              value: 'en'
+
+  responses:
+    '200':
+      description: Setting stored or updated successfully
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: '../components/schemas/Success.yaml'
+              - type: object
+                properties:
+                  data:
+                    $ref: '../components/schemas/SettingSetResult.yaml'
+          examples:
+            updated:
+              value:
+                result: success
+                data:
+                  action: 'updated'
+            added:
+              value:
+                result: success
+                data:
+                  action: 'added'
+
+    '400':
+      description: INVALID - Missing or malformed fields.
+      content:
+        application/json:
+          schema:
+            $ref: '../components/schemas/Error.yaml'
+          examples:
+            invalid:
+              value:
+                result: 'error'
+                error: 'Missing required field: name'
+                code: 'ER_INVALID_ARGUMENT'
+
+    '401':
+      description: UNAUTHORIZED - Auth token missing or invalid.
+      content:
+        application/json:
+          schema:
+            $ref: '../components/schemas/Error.yaml'
+          examples:
+            unauthorized:
+              value:
+                result: 'error'
+                error: 'UNAUTHORIZED'
+                code: 'ER_UNAUTHORIZED'
+
+    '409':
+      description: CONFLICT - Setting with same or newer timestamp already exists.
+      content:
+        application/json:
+          schema:
+            $ref: '../components/schemas/Error.yaml'
+          examples:
+            conflict:
+              value:
+                result: 'error'
+                error: 'Newer setting already exists'
+                code: 'ER_CONFLICT'
+                sub_code: 'ER_OLD_ENTRY'
+
+get:
+  summary: Get user settings
+  description: Returns settings for the authenticated user.
+  operationId: getUserSettings
+  tags:
+    - User-Settings
+  security:
+    - bearerAuth: []
+
+  responses:
+    '200':
+      description: User settings fetched successfully
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: '../components/schemas/Success.yaml'
+              - type: object
+                required:
+                  - data
+                properties:
+                  data:
+                    type: object
+                    required:
+                      - settings
+                    properties:
+                      settings:
+                        $ref: '../components/schemas/UserSettingObject.yaml'
+          examples:
+            basic:
+              value:
+                result: success
+                data:
+                  settings:
+                    PROFILE_LANGUAGE_CODE: 'en'
+                    PROFILE_LANGUAGE_CODE_lastUpdated: 1732187742
+                    UNIT_TEMPERATURE: 'C'
+                    UNIT_TEMPERATURE_lastUpdated: 1732187742
+
+    '401':
+      description: UNAUTHORIZED - Auth token missing or invalid.
+      content:
+        application/json:
+          schema:
+            $ref: '../components/schemas/Error.yaml'
+          examples:
+            unauthorized:
+              value:
+                result: 'error'
+                error: 'UNAUTHORIZED'
+                code: 'ER_UNAUTHORIZED'