diff --git a/docs/for-developers/configuration/gateway.md b/docs/for-developers/configuration/gateway.md
index dac49f8061a40a15096ab0437e200330a54ebfac..2b16dacfcbdfbc415f9091c3086a000032787d21 100644
--- a/docs/for-developers/configuration/gateway.md
+++ b/docs/for-developers/configuration/gateway.md
@@ -10,15 +10,14 @@ description: >-
 
 #### General
 
-| name               | type    | default                         | description                                                                                                                                                                  |
-| ------------------ | ------- | ------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| ENGINE\_TYPE       | string  | exareme                         | Define the connector that should be used : **`exareme, datashield, csv, local`**.                                                                                            |
-| ENGINE\_BASE\_URL  | string  | http://127.0.0.1:8080/services/ | Specify the endpoint for the data source. The parameter will be provided for the connector.                                                                                  |
-| TOS\_SKIP          | boolean | false                           | Allow to skip the `terms of services` (this parameter is provided to the frontend)                                                                                           |
-| GATEWAY\_PORT      | number  | 8081                            | Indicate the port that should be used by the gateway                                                                                                                         |
-| NODE\_ENV          | string  | dev                             | Value can be `prod` or `dev`                                                                                                                                                 |
-| LOG\_LEVEL         | number  | 1 in production, 4 otherwise    | <p>Values in range [1;4] <br>1: 'warn', 'error'<br>2: 'warn', 'error', 'log'</p><p>3: 'warn', 'error', 'log', 'verbose'<br>4: 'warn', 'error', 'log', 'verbose', 'debug'</p> |
-| BASE\_URL\_CONTEXT | string  | null                            | Define context of the gateway. E.g. `api` if the api is under `http://127.0.0.1/api/`                                                                                        |
+| name               | type    | default                         | description                                                                                 |
+| ------------------ | ------- | ------------------------------- | ------------------------------------------------------------------------------------------- |
+| ENGINE\_TYPE       | string  | exareme                         | Define the connector that should be used : **`exareme, datashield, csv, local`**.           |
+| ENGINE\_BASE\_URL  | string  | http://127.0.0.1:8080/services/ | Specify the endpoint for the data source. The parameter will be provided for the connector. |
+| TOS\_SKIP          | boolean | false                           | Allow to skip the `terms of services` (this parameter is provided to the frontend)          |
+| GATEWAY\_PORT      | number  | 8081                            | Indicate the port that should be used by the gateway                                        |
+| NODE\_ENV          | string  | dev                             | Value can be `prod` or `dev`                                                                |
+| BASE\_URL\_CONTEXT | string  | null                            | Define context of the gateway. E.g. `api` if the api is under `http://127.0.0.1/api/`       |
 
 #### Authentication
 
diff --git a/docs/for-developers/gateway/authentication.md b/docs/for-developers/gateway/authentication.md
index 6c8a63fa9d5e7bf3a606cca9069b135d6301f6f9..7e6f9bbc908a578da5b9966ae2f8a406cd49add5 100644
--- a/docs/for-developers/gateway/authentication.md
+++ b/docs/for-developers/gateway/authentication.md
@@ -48,9 +48,9 @@ This field can be used by the connector to store information related to the user
 
 The real login system is delegated to the connector by using the `login` method in the interface.
 
-{% code title="engine.interface.ts" %}
+{% code title="connector.interface.ts" %}
 ```typescript
-export interface IEngineService {
+export interface Connector {
   // ...
   
   /**
@@ -77,9 +77,9 @@ When the login is performed, this function should return a `User` object and can
 
 The same mechanism is applied to the logout system using the method logout from the engine.
 
-{% code title="engine.interface.ts" %}
+{% code title="connector.interface.ts" %}
 ```typescript
-export interface IEngineService {
+export interface Connector {
   // ...
   
   logout?(req: Request
@@ -90,3 +90,37 @@ export interface IEngineService {
 ```
 {% endcode %}
 
+#### Session validation
+
+Whenever a Frontend required a refreshToken, the gateway should tell if the user is still connected to the engine. For this, your connector should implements the function **isSessionValid**.&#x20;
+
+{% code title="connector.interface.ts" %}
+```typescript
+export interface Connector {
+  // ...
+  
+  isSessionValid?(user: User): Promise<boolean>;
+
+  // ...
+}
+```
+{% endcode %}
+
+This function should ensure that the user can still access the engine with the current token.
+
+#### How to get the user&#x20;
+
+Whether you use the local login or a 3rd party system, there is a unique way to access the user inside the Gateway. This method through the request :&#x20;
+
+```typescript
+request.user
+```
+
+This request's attribute is feed by strategy policies defined in the Gateway. Currently the following strategies are applied&#x20;
+
+1. JWT cookies
+2. JWT bearer
+3. Engine (use the connector to retrieve the user)
+
+Even if the `AUTH_SKIP` is defined you should be able to retrieve the user through the request.
+