diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 0000000..a4538ba
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,5 @@
+{
+  "semi": true,
+  "singleQuote": true,
+  "printWidth": 80
+}
diff --git a/package-lock.json b/package-lock.json
index 259b1cb..5e4889d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,11 +1,11 @@
 {
-  "name": "@icynet/oauth2",
+  "name": "@icynet/oauth2-provider",
   "version": "1.0.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
-      "name": "@icynet/oauth2",
+      "name": "@icynet/oauth2-provider",
       "version": "1.0.0",
       "license": "MIT",
       "dependencies": {
@@ -16,6 +16,7 @@
         "@types/express": "^4.17.13",
         "@types/express-session": "^1.17.4",
         "@types/node": "^17.0.21",
+        "prettier": "^2.5.1",
         "typescript": "^4.5.5"
       }
     },
@@ -470,6 +471,18 @@
       "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-0.1.7.tgz",
       "integrity": "sha1-32BBeABfUi8V60SQ5yR6G/qmf4w="
     },
+    "node_modules/prettier": {
+      "version": "2.5.1",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.5.1.tgz",
+      "integrity": "sha512-vBZcPRUR5MZJwoyi3ZoyQlc1rXeEck8KgeC9AwwOn+exuxLxq5toTRDTSaVrXHxelDMHy9zlicw8u66yxoSUFg==",
+      "dev": true,
+      "bin": {
+        "prettier": "bin-prettier.js"
+      },
+      "engines": {
+        "node": ">=10.13.0"
+      }
+    },
     "node_modules/proxy-addr": {
       "version": "2.0.7",
       "resolved": "https://registry.npmjs.org/proxy-addr/-/proxy-addr-2.0.7.tgz",
@@ -1038,6 +1051,12 @@
       "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-0.1.7.tgz",
       "integrity": "sha1-32BBeABfUi8V60SQ5yR6G/qmf4w="
     },
+    "prettier": {
+      "version": "2.5.1",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.5.1.tgz",
+      "integrity": "sha512-vBZcPRUR5MZJwoyi3ZoyQlc1rXeEck8KgeC9AwwOn+exuxLxq5toTRDTSaVrXHxelDMHy9zlicw8u66yxoSUFg==",
+      "dev": true
+    },
     "proxy-addr": {
       "version": "2.0.7",
       "resolved": "https://registry.npmjs.org/proxy-addr/-/proxy-addr-2.0.7.tgz",
diff --git a/package.json b/package.json
index f4c18ca..f8601c6 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,7 @@
     "@types/express": "^4.17.13",
     "@types/express-session": "^1.17.4",
     "@types/node": "^17.0.21",
+    "prettier": "^2.5.1",
     "typescript": "^4.5.5"
   },
   "dependencies": {
diff --git a/src/controller/authorization.ts b/src/controller/authorization.ts
index cbe25bb..6168421 100644
--- a/src/controller/authorization.ts
+++ b/src/controller/authorization.ts
@@ -24,59 +24,75 @@ export const authorization = wrap(async (req, res) => {
   const { oauth2 } = req;
 
   if (!req.query.redirect_uri) {
-    throw new InvalidRequest('redirect_uri field is mandatory for authorization endpoint');
+    throw new InvalidRequest(
+      'redirect_uri field is mandatory for authorization endpoint'
+    );
   }
 
   redirectUri = req.query.redirect_uri as string;
-  console.debug('Parameter redirect uri is', redirectUri);
+  req.oauth2.logger.debug('Parameter redirect uri is', redirectUri);
 
   if (!req.query.client_id) {
-    throw new InvalidRequest('client_id field is mandatory for authorization endpoint');
+    throw new InvalidRequest(
+      'client_id field is mandatory for authorization endpoint'
+    );
   }
 
   // Check for client_secret (prevent passing it)
   if (req.query.client_secret) {
-    throw new InvalidRequest('client_secret field should not be passed to the authorization endpoint');
+    throw new InvalidRequest(
+      'client_secret field should not be passed to the authorization endpoint'
+    );
   }
 
   clientId = req.query.client_id as string;
-  console.debug('Parameter client_id is', clientId);
+  req.oauth2.logger.debug('Parameter client_id is', clientId);
 
   if (!req.query.response_type) {
-    throw new InvalidRequest('response_type field is mandatory for authorization endpoint');
+    throw new InvalidRequest(
+      'response_type field is mandatory for authorization endpoint'
+    );
   }
 
   responseType = req.query.response_type as string;
-  console.debug('Parameter response_type is', responseType);
+  req.oauth2.logger.debug('Parameter response_type is', responseType);
 
   // Support multiple types
   const responseTypes = responseType.split(' ');
   for (const i in responseTypes) {
     switch (responseTypes[i]) {
-    case 'code':
-      grantTypes.push('authorization_code');
-      break;
-    case 'token':
-      grantTypes.push('implicit');
-      break;
-      // case 'id_token':
-    case 'none':
-      grantTypes.push(responseTypes[i]);
-      break;
-    default:
-      throw new UnsupportedResponseType('Unknown response_type parameter passed');
+      case 'code':
+        grantTypes.push('authorization_code');
+        break;
+      case 'token':
+        grantTypes.push('implicit');
+        break;
+      case 'id_token':
+        grantTypes.push('id_token');
+        break;
+      case 'none':
+        grantTypes.push(responseTypes[i]);
+        break;
+      default:
+        throw new UnsupportedResponseType(
+          'Unknown response_type parameter passed'
+        );
     }
   }
 
   // Filter out duplicates
-  grantTypes = grantTypes.filter((value, index, self) => self.indexOf(value) === index);
+  grantTypes = grantTypes.filter(
+    (value, index, self) => self.indexOf(value) === index
+  );
 
   // "None" type cannot be combined with others
   if (grantTypes.length > 1 && grantTypes.indexOf('none') !== -1) {
-    throw new InvalidRequest('Grant type "none" cannot be combined with other grant types');
+    throw new InvalidRequest(
+      'Grant type "none" cannot be combined with other grant types'
+    );
   }
 
-  console.debug('Parameter grant_type is', grantTypes.join(' '));
+  req.oauth2.logger.debug('Parameter grant_type is', grantTypes.join(' '));
 
   const client = await oauth2.model.client.fetchById(clientId);
   if (!client) {
@@ -89,21 +105,26 @@ export const authorization = wrap(async (req, res) => {
   } else if (!oauth2.model.client.checkRedirectUri(client, redirectUri)) {
     throw new InvalidRequest('Wrong RedirectUri provided');
   }
-  console.debug('redirect_uri check passed');
+  req.oauth2.logger.debug('redirect_uri check passed');
 
   // The client needs to support all grant types
   for (const grantType of grantTypes) {
-    if (!oauth2.model.client.checkGrantType(client, grantType) && grantType !== 'none') {
-      throw new UnauthorizedClient('This client does not support grant type ' + grantType);
+    if (
+      !oauth2.model.client.checkGrantType(client, grantType) &&
+      grantType !== 'none'
+    ) {
+      throw new UnauthorizedClient(
+        'This client does not support grant type ' + grantType
+      );
     }
   }
-  console.debug('Grant type check passed');
+  req.oauth2.logger.debug('Grant type check passed');
 
   scope = oauth2.model.client.transformScope(req.query.scope as string);
   if (!oauth2.model.client.checkScope(client, scope)) {
     throw new InvalidScope('Client does not allow access to this scope');
   }
-  console.debug('Scope check passed');
+  req.oauth2.logger.debug('Scope check passed');
 
   user = await oauth2.model.user.fetchFromRequest(req);
   if (!user) {
@@ -112,10 +133,10 @@ export const authorization = wrap(async (req, res) => {
     if (!user.username) {
       throw new AccessDenied(user.username);
     }
-    console.debug('User fetched from request')
+    req.oauth2.logger.debug('User fetched from request');
   }
 
-  let resObj = {};
+  let resObj: Record<string, string | number> = {};
   let consented = false;
 
   if (req.method === 'GET') {
@@ -128,24 +149,31 @@ export const authorization = wrap(async (req, res) => {
     );
 
     // Ask for consent
-    if (!consented) return oauth2.decision(req, res, client, scope, user, redirectUri);
+    if (!consented)
+      return oauth2.decision(req, res, client, scope, user, redirectUri);
   }
 
   // Consent pushed, ensure valid session
-  const { session: { csrf } } = req;
-  if (req.method === 'POST' && csrf && !(req.body.csrf && req.body.csrf === csrf)) {
+  const {
+    session: { csrf },
+  } = req;
+  if (
+    req.method === 'POST' &&
+    csrf &&
+    !(req.body.csrf && req.body.csrf === csrf)
+  ) {
     throw new InvalidRequest('Invalid session');
   }
 
   // Save consent
   if (!consented) {
-    if (!req.body || (typeof req.body.decision) === 'undefined') {
+    if (!req.body || typeof req.body.decision === 'undefined') {
       throw new InvalidRequest('No decision parameter passed');
     } else if (req.body.decision === '0') {
       throw new AccessDenied('User denied access to the resource');
     }
 
-    console.debug('Decision check passed');
+    req.oauth2.logger.debug('Decision check passed');
 
     await oauth2.model.user.consent(
       oauth2.model.user.getId(user),
@@ -155,39 +183,57 @@ export const authorization = wrap(async (req, res) => {
   }
 
   for (const i in grantTypes) {
-    let data = null
+    let data = null;
     switch (grantTypes[i]) {
-    case 'authorization_code':
-      data = await oauth2.model.code.create(
-        oauth2.model.user.getId(user),
-        oauth2.model.client.getId(client),
-        scope,
-        oauth2.model.code.ttl,
-      );
+      case 'authorization_code':
+        data = await oauth2.model.code.create(
+          oauth2.model.user.getId(user),
+          oauth2.model.client.getId(client),
+          scope,
+          oauth2.model.code.ttl
+        );
 
-      resObj = Object.assign({ code: data }, resObj);
+        resObj = { code: data, ...resObj };
 
-      break;
-    case 'implicit':
-      data = await oauth2.model.accessToken.create(
-        oauth2.model.user.getId(user),
-        oauth2.model.client.getId(client),
-        scope,
-        oauth2.model.accessToken.ttl
-      );
+        break;
+      case 'implicit':
+        data = await oauth2.model.accessToken.create(
+          oauth2.model.user.getId(user),
+          oauth2.model.client.getId(client),
+          scope,
+          oauth2.model.accessToken.ttl
+        );
 
-      resObj = Object.assign({
-        token_type: 'bearer',
-        access_token: data,
-        expires_in: oauth2.model.accessToken.ttl
-      }, resObj);
+        resObj = {
+          token_type: 'bearer',
+          access_token: data,
+          expires_in: oauth2.model.accessToken.ttl,
+          ...resObj,
+        };
 
-      break;
-    case 'none':
-      resObj = {};
-      break;
-    default:
-      throw new UnsupportedResponseType('Unknown response_type parameter passed');
+        break;
+      case 'id_token':
+        if (!oauth2.model.jwt || !scope.includes('openid')) {
+          break;
+        }
+
+        data = await oauth2.model.jwt.issueIdToken(
+          user,
+          scope,
+          resObj.access_token as string | undefined
+        );
+
+        resObj = {
+          id_token: data,
+          ...resObj,
+        };
+      case 'none':
+        resObj = {};
+        break;
+      default:
+        throw new UnsupportedResponseType(
+          'Unknown response_type parameter passed'
+        );
     }
   }
 
diff --git a/src/controller/introspection.ts b/src/controller/introspection.ts
index c9da32a..9fdb2d8 100644
--- a/src/controller/introspection.ts
+++ b/src/controller/introspection.ts
@@ -11,7 +11,11 @@ export const introspection = wrap(async function (req, res) {
   if (req.body.client_id && req.body.client_secret) {
     clientId = req.body.client_id as string;
     clientSecret = req.body.client_secret as string;
-    console.debug('Client credentials parsed from body parameters ', clientId, clientSecret);
+    req.oauth2.logger.debug(
+      'Client credentials parsed from body parameters ',
+      clientId,
+      clientSecret
+    );
   } else {
     if (!req.headers || !req.headers.authorization) {
       throw new InvalidRequest('No authorization header passed');
@@ -23,7 +27,9 @@ export const introspection = wrap(async function (req, res) {
     }
 
     if (pieces[0] !== 'Basic') {
-      throw new InvalidRequest(`Unsupported authorization method: ${pieces[0]}`);
+      throw new InvalidRequest(
+        `Unsupported authorization method: ${pieces[0]}`
+      );
     }
 
     pieces = Buffer.from(pieces[1], 'base64').toString('ascii').split(':', 2);
@@ -33,7 +39,11 @@ export const introspection = wrap(async function (req, res) {
 
     clientId = pieces[0];
     clientSecret = pieces[1];
-    console.debug('Client credentials parsed from basic auth header: ', clientId, clientSecret);
+    req.oauth2.logger.debug(
+      'Client credentials parsed from basic auth header: ',
+      clientId,
+      clientSecret
+    );
   }
 
   if (!req.body.token) {
@@ -49,7 +59,7 @@ export const introspection = wrap(async function (req, res) {
   const resObj = {
     token_type: 'bearer',
     token: token.token,
-    expires_in: Math.floor(ttl / 1000)
+    expires_in: Math.floor(ttl / 1000),
   };
 
   dataResponse(req, res, resObj);
diff --git a/src/controller/token.ts b/src/controller/token.ts
index 847e011..8336437 100644
--- a/src/controller/token.ts
+++ b/src/controller/token.ts
@@ -1,13 +1,16 @@
-import * as tokens from './tokens'
+import * as tokens from './tokens';
 import {
   InvalidRequest,
   InvalidClient,
   UnauthorizedClient,
   UnsupportedGrantType,
-  OAuth2Error
-} from '../model/error'
-import { data as dataResponse, error as errorResponse } from '../utils/response'
-import wrap from '../utils/wrap'
+  OAuth2Error,
+} from '../model/error';
+import {
+  data as dataResponse,
+  error as errorResponse,
+} from '../utils/response';
+import wrap from '../utils/wrap';
 import { OAuth2TokenResponse } from '../model/model';
 
 export const token = wrap(async (req, res) => {
@@ -20,7 +23,11 @@ export const token = wrap(async (req, res) => {
   if (req.body.client_id && req.body.client_secret) {
     clientId = req.body.client_id as string;
     clientSecret = req.body.client_secret as string;
-    console.debug('Client credentials parsed from body parameters', clientId, clientSecret);
+    req.oauth2.logger.debug(
+      'Client credentials parsed from body parameters',
+      clientId,
+      clientSecret
+    );
   } else {
     if (!req.headers || !req.headers.authorization) {
       throw new InvalidRequest('No authorization header passed');
@@ -32,7 +39,9 @@ export const token = wrap(async (req, res) => {
     }
 
     if (pieces[0] !== 'Basic') {
-      throw new InvalidRequest(`Unsupported authorization method: ${pieces[0]}`);
+      throw new InvalidRequest(
+        `Unsupported authorization method: ${pieces[0]}`
+      );
     }
 
     pieces = Buffer.from(pieces[1], 'base64').toString('ascii').split(':', 2);
@@ -42,15 +51,21 @@ export const token = wrap(async (req, res) => {
 
     clientId = pieces[0];
     clientSecret = pieces[1];
-    console.debug('Client credentials parsed from basic auth header:', clientId, clientSecret);
+    req.oauth2.logger.debug(
+      'Client credentials parsed from basic auth header:',
+      clientId,
+      clientSecret
+    );
   }
 
   if (!req.body.grant_type) {
-    throw new InvalidRequest('Request body does not contain grant_type parameter');
+    throw new InvalidRequest(
+      'Request body does not contain grant_type parameter'
+    );
   }
 
   grantType = req.body.grant_type as string;
-  console.debug('Parameter grant_type is', grantType);
+  req.oauth2.logger.debug('Parameter grant_type is', grantType);
 
   const client = await oauth2.model.client.fetchById(clientId);
 
@@ -63,36 +78,58 @@ export const token = wrap(async (req, res) => {
     throw new UnauthorizedClient('Invalid client secret');
   }
 
-  if (!oauth2.model.client.checkGrantType(client, grantType) && grantType !== 'refresh_token') {
+  if (
+    !oauth2.model.client.checkGrantType(client, grantType) &&
+    grantType !== 'refresh_token'
+  ) {
     throw new UnauthorizedClient('Invalid grant type for the client');
   } else {
-    console.debug('Grant type check passed');
+    req.oauth2.logger.debug('Grant type check passed');
   }
 
   let tokenResponse: OAuth2TokenResponse;
   try {
     switch (grantType) {
-    case 'authorization_code':
-      tokenResponse = await tokens.authorizationCode(oauth2, client, req.body.code);
-      break;
-    case 'password':
-      tokenResponse = await tokens.password(oauth2, client, req.body.username, req.body.password, req.body.scope);
-      break;
-    case 'client_credentials':
-      tokenResponse = await tokens.clientCredentials(oauth2, client, req.body.scope);
-      break;
-    case 'refresh_token':
-      tokenResponse = await tokens.refreshToken(oauth2, client, req.body.refresh_token);
-      break;
-    default:
-      throw new UnsupportedGrantType('Grant type does not match any supported type');
+      case 'authorization_code':
+        tokenResponse = await tokens.authorizationCode(
+          oauth2,
+          client,
+          req.body.code
+        );
+        break;
+      case 'password':
+        tokenResponse = await tokens.password(
+          oauth2,
+          client,
+          req.body.username,
+          req.body.password,
+          req.body.scope
+        );
+        break;
+      case 'client_credentials':
+        tokenResponse = await tokens.clientCredentials(
+          oauth2,
+          client,
+          req.body.scope
+        );
+        break;
+      case 'refresh_token':
+        tokenResponse = await tokens.refreshToken(
+          oauth2,
+          client,
+          req.body.refresh_token
+        );
+        break;
+      default:
+        throw new UnsupportedGrantType(
+          'Grant type does not match any supported type'
+        );
     }
 
     if (tokenResponse) {
       dataResponse(req, res, tokenResponse);
     }
-
   } catch (e) {
     errorResponse(req, res, e as OAuth2Error);
   }
-})
+});
diff --git a/src/controller/tokens/authorizationCode.ts b/src/controller/tokens/authorizationCode.ts
index ba2ab71..c3b08b0 100644
--- a/src/controller/tokens/authorizationCode.ts
+++ b/src/controller/tokens/authorizationCode.ts
@@ -1,5 +1,10 @@
 import { InvalidRequest, ServerError, InvalidGrant } from '../../model/error';
-import { OAuth2, OAuth2Client, OAuth2Code, OAuth2TokenResponse } from '../../model/model';
+import {
+  OAuth2,
+  OAuth2Client,
+  OAuth2Code,
+  OAuth2TokenResponse,
+} from '../../model/model';
 
 /**
  * Issue an access token by authorization code
@@ -14,24 +19,28 @@ export async function authorizationCode(
   providedCode: string
 ): Promise<OAuth2TokenResponse> {
   const respObj: OAuth2TokenResponse = {
-    token_type: 'bearer'
+    token_type: 'bearer',
   };
 
   let code: OAuth2Code | null = null;
 
   if (!providedCode) {
-    throw new InvalidRequest('code is mandatory for authorization_code grant type');
+    throw new InvalidRequest(
+      'code is mandatory for authorization_code grant type'
+    );
   }
 
   try {
     code = await oauth2.model.code.fetchByCode(providedCode);
   } catch (err) {
-    console.error(err);
+    oauth2.logger.error(err);
     throw new ServerError('Failed to call code.fetchByCode function');
   }
 
   if (code) {
-    if (oauth2.model.code.getClientId(code) !== oauth2.model.client.getId(client)) {
+    if (
+      oauth2.model.code.getClientId(code) !== oauth2.model.client.getId(client)
+    ) {
       throw new InvalidGrant('Code was issued by another client');
     }
 
@@ -42,56 +51,81 @@ export async function authorizationCode(
     throw new InvalidGrant('Code not found');
   }
 
-  console.debug('Code fetched', code);
+  oauth2.logger.debug('Code fetched', code);
 
-  try {
-    await oauth2.model.refreshToken.removeByUserIdClientId(
-      oauth2.model.code.getUserId(code),
-      oauth2.model.code.getClientId(code)
-    );
-  } catch (err) {
-    console.error(err)
-    throw new ServerError('Failed to call refreshToken.removeByUserIdClientId function');
+  const scope = oauth2.model.code.getScope(code);
+  const cleanScope = oauth2.model.client.transformScope(scope);
+  const userId = oauth2.model.code.getUserId(code);
+  const clientId = oauth2.model.code.getClientId(code);
+
+  if (oauth2.model.refreshToken.invalidateOld) {
+    try {
+      await oauth2.model.refreshToken.removeByUserIdClientId(userId, clientId);
+    } catch (err) {
+      oauth2.logger.error(err);
+      throw new ServerError(
+        'Failed to call refreshToken.removeByUserIdClientId function'
+      );
+    }
+
+    oauth2.logger.debug('Refresh token removed');
   }
 
-  console.debug('Refresh token removed');
-
   if (!oauth2.model.client.checkGrantType(client, 'refresh_token')) {
-    console.debug('Client does not allow grant type refresh_token, skip creation');
+    oauth2.logger.debug(
+      'Client does not allow grant type refresh_token, skip creation'
+    );
   } else {
     try {
       respObj.refresh_token = await oauth2.model.refreshToken.create(
-        oauth2.model.code.getUserId(code),
-        oauth2.model.code.getClientId(code),
-        oauth2.model.code.getScope(code)
+        userId,
+        clientId,
+        scope
       );
     } catch (err) {
-      console.error(err);
+      oauth2.logger.error(err);
       throw new ServerError('Failed to call refreshToken.create function');
     }
   }
 
   try {
     respObj.access_token = await oauth2.model.accessToken.create(
-      oauth2.model.code.getUserId(code),
-      oauth2.model.code.getClientId(code),
-      oauth2.model.code.getScope(code),
+      userId,
+      clientId,
+      scope,
       oauth2.model.accessToken.ttl
     );
   } catch (err) {
-    console.error(err);
+    oauth2.logger.error(err);
     throw new ServerError('Failed to call accessToken.create function');
   }
 
   respObj.expires_in = oauth2.model.accessToken.ttl;
-  console.debug('Access token saved:', respObj.access_token);
+  oauth2.logger.debug('Access token saved:', respObj.access_token);
 
   try {
     await oauth2.model.code.removeByCode(providedCode);
   } catch (err) {
-    console.error(err);
+    oauth2.logger.error(err);
     throw new ServerError('Failed to call code.removeByCode function');
   }
 
+  if (cleanScope.includes('openid') && oauth2.model.jwt) {
+    const user = await oauth2.model.user.fetchById(
+      oauth2.model.code.getUserId(code)
+    );
+
+    try {
+      respObj.id_token = await oauth2.model.jwt.issueIdToken(
+        user,
+        cleanScope,
+        respObj.access_token
+      );
+    } catch (err) {
+      oauth2.logger.error(err);
+      throw new ServerError('Failed to issue an ID token');
+    }
+  }
+
   return respObj;
 }
diff --git a/src/controller/tokens/clientCredentials.ts b/src/controller/tokens/clientCredentials.ts
index e2a0035..8fc2e30 100644
--- a/src/controller/tokens/clientCredentials.ts
+++ b/src/controller/tokens/clientCredentials.ts
@@ -1,4 +1,4 @@
-import { ServerError, InvalidScope } from '../../model/error'
+import { ServerError, InvalidScope } from '../../model/error';
 import { OAuth2, OAuth2Client, OAuth2TokenResponse } from '../../model/model';
 
 /**
@@ -16,7 +16,7 @@ export async function clientCredentials(
   let scope: string[] = [];
 
   const resObj: OAuth2TokenResponse = {
-    token_type: 'bearer'
+    token_type: 'bearer',
   };
 
   scope = oauth2.model.client.transformScope(wantScope);
@@ -24,7 +24,7 @@ export async function clientCredentials(
     throw new InvalidScope('Client does not allow access to this scope');
   }
 
-  console.debug('Scope check passed ', scope);
+  oauth2.logger.debug('Scope check passed', scope);
 
   try {
     resObj.access_token = await oauth2.model.accessToken.create(
diff --git a/src/controller/tokens/index.ts b/src/controller/tokens/index.ts
index 24e814c..dc499b1 100644
--- a/src/controller/tokens/index.ts
+++ b/src/controller/tokens/index.ts
@@ -1,4 +1,4 @@
-export * from './authorizationCode'
-export * from './clientCredentials'
-export * from './password'
-export * from './refreshToken'
+export * from './authorizationCode';
+export * from './clientCredentials';
+export * from './password';
+export * from './refreshToken';
diff --git a/src/controller/tokens/password.ts b/src/controller/tokens/password.ts
index 0e68449..46d6b48 100644
--- a/src/controller/tokens/password.ts
+++ b/src/controller/tokens/password.ts
@@ -1,12 +1,22 @@
-import { ServerError, InvalidRequest, InvalidScope, InvalidClient } from '../../model/error'
-import { OAuth2, OAuth2Client, OAuth2User, OAuth2TokenResponse } from '../../model/model';
+import {
+  ServerError,
+  InvalidRequest,
+  InvalidScope,
+  InvalidClient,
+} from '../../model/error';
+import {
+  OAuth2,
+  OAuth2Client,
+  OAuth2User,
+  OAuth2TokenResponse,
+} from '../../model/model';
 
 /**
  * Implicit access token response
  * @param oauth2 - OAuth2 instance
  * @param client - OAuth2 client
  * @param username
- * @param password 
+ * @param password
  * @param scope - Requested scopes
  * @returns Access token
  */
@@ -20,8 +30,8 @@ export async function password(
   let user: OAuth2User | null = null;
 
   const resObj: OAuth2TokenResponse = {
-    token_type: 'bearer'
-  }
+    token_type: 'bearer',
+  };
 
   if (!username) {
     throw new InvalidRequest('Username is mandatory for password grant type');
@@ -35,7 +45,7 @@ export async function password(
   if (!oauth2.model.client.checkScope(client, scope)) {
     throw new InvalidScope('Client does not allow access to this scope');
   } else {
-    console.debug('Scope check passed: ', scope);
+    oauth2.logger.debug('Scope check passed: ', scope);
   }
 
   try {
@@ -59,13 +69,17 @@ export async function password(
       oauth2.model.client.getId(client)
     );
   } catch (err) {
-    throw new ServerError('Failed to call refreshToken.removeByUserIdClientId function');
+    throw new ServerError(
+      'Failed to call refreshToken.removeByUserIdClientId function'
+    );
   }
 
-  console.debug('Refresh token removed');
+  oauth2.logger.debug('Refresh token removed');
 
   if (!oauth2.model.client.checkGrantType(client, 'refresh_token')) {
-    console.debug('Client does not allow grant type refresh_token, skip creation');
+    oauth2.logger.debug(
+      'Client does not allow grant type refresh_token, skip creation'
+    );
   } else {
     try {
       resObj.refresh_token = await oauth2.model.refreshToken.create(
@@ -90,7 +104,7 @@ export async function password(
   }
 
   resObj.expires_in = oauth2.model.accessToken.ttl;
-  console.debug('Access token saved ', resObj.access_token);
+  oauth2.logger.debug('Access token saved ', resObj.access_token);
 
   return resObj;
 }
diff --git a/src/controller/tokens/refreshToken.ts b/src/controller/tokens/refreshToken.ts
index 90d94a8..91d5d18 100644
--- a/src/controller/tokens/refreshToken.ts
+++ b/src/controller/tokens/refreshToken.ts
@@ -1,24 +1,29 @@
-import { InvalidRequest, ServerError, InvalidGrant, InvalidClient } from '../../model/error';
+import {
+  InvalidRequest,
+  ServerError,
+  InvalidGrant,
+  InvalidClient,
+} from '../../model/error';
 import {
   OAuth2,
   OAuth2AccessToken,
   OAuth2Client,
   OAuth2RefreshToken,
   OAuth2User,
-  OAuth2TokenResponse
+  OAuth2TokenResponse,
 } from '../../model/model';
 
 /**
  * Get a new access token from a refresh token. Scope change may not be requested.
  * @param oauth2 - OAuth2 instance
  * @param client - OAuth2 client
- * @param pRefreshToken - Refresh token
+ * @param providedToken - Refresh token
  * @returns Access token
  */
 export async function refreshToken(
   oauth2: OAuth2,
   client: OAuth2Client,
-  pRefreshToken: string,
+  providedToken: string
 ): Promise<OAuth2TokenResponse> {
   let user: OAuth2User | null = null;
   let ttl: number | null = null;
@@ -26,15 +31,17 @@ export async function refreshToken(
   let accessToken: OAuth2AccessToken | null = null;
 
   const resObj: OAuth2TokenResponse = {
-    token_type: 'bearer'
+    token_type: 'bearer',
   };
 
-  if (!pRefreshToken) {
-    throw new InvalidRequest('refresh_token is mandatory for refresh_token grant type');
+  if (!providedToken) {
+    throw new InvalidRequest(
+      'refresh_token is mandatory for refresh_token grant type'
+    );
   }
 
   try {
-    refreshToken = await oauth2.model.refreshToken.fetchByToken(pRefreshToken);
+    refreshToken = await oauth2.model.refreshToken.fetchByToken(providedToken);
   } catch (err) {
     throw new ServerError('Failed to call refreshToken.fetchByToken function');
   }
@@ -43,8 +50,12 @@ export async function refreshToken(
     throw new InvalidGrant('Refresh token not found');
   }
 
-  if (oauth2.model.refreshToken.getClientId(refreshToken) !== oauth2.model.client.getId(client)) {
-    console.warn('Client %s tried to fetch a refresh token which belongs to client %s!',
+  if (
+    oauth2.model.refreshToken.getClientId(refreshToken) !==
+    oauth2.model.client.getId(client)
+  ) {
+    oauth2.logger.warn(
+      'Client %s tried to fetch a refresh token which belongs to client %s!',
       oauth2.model.client.getId(client),
       oauth2.model.refreshToken.getClientId(refreshToken)
     );
@@ -52,7 +63,9 @@ export async function refreshToken(
   }
 
   try {
-    user = await oauth2.model.user.fetchById(oauth2.model.refreshToken.getUserId(refreshToken));
+    user = await oauth2.model.user.fetchById(
+      oauth2.model.refreshToken.getUserId(refreshToken)
+    );
   } catch (err) {
     throw new InvalidClient('User not found');
   }
@@ -62,10 +75,14 @@ export async function refreshToken(
   }
 
   try {
-    accessToken = await oauth2.model.accessToken.fetchByUserIdClientId(oauth2.model.user.getId(user),
-      oauth2.model.client.getId(client));
+    accessToken = await oauth2.model.accessToken.fetchByUserIdClientId(
+      oauth2.model.user.getId(user),
+      oauth2.model.client.getId(client)
+    );
   } catch (err) {
-    throw new ServerError('Failed to call accessToken.fetchByUserIdClientId function');
+    throw new ServerError(
+      'Failed to call accessToken.fetchByUserIdClientId function'
+    );
   }
 
   if (accessToken) {
diff --git a/src/middleware.ts b/src/middleware.ts
index 6c86e87..f2cd9a0 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -3,7 +3,7 @@ import { AccessDenied } from './model/error';
 import wrap from './utils/wrap';
 
 export const middleware = wrap(async function (req: Request, res, next) {
-  console.debug('Parsing bearer token');
+  req.oauth2.logger.debug('Parsing bearer token');
   let token = null;
 
   // Look for token in header
@@ -21,13 +21,16 @@ export const middleware = wrap(async function (req: Request, res, next) {
     }
 
     token = pieces[1];
-    console.debug('Bearer token parsed from authorization header:', token);
+    req.oauth2.logger.debug(
+      'Bearer token parsed from authorization header:',
+      token
+    );
   } else if (req.query?.access_token) {
     token = req.query.access_token;
-    console.debug('Bearer token parsed from query params:', token);
+    req.oauth2.logger.debug('Bearer token parsed from query params:', token);
   } else if (req.body?.access_token) {
     token = req.body.access_token;
-    console.debug('Bearer token parsed from body params:', token);
+    req.oauth2.logger.debug('Bearer token parsed from body params:', token);
   } else {
     throw new AccessDenied('Bearer token not found');
   }
@@ -40,7 +43,7 @@ export const middleware = wrap(async function (req: Request, res, next) {
     throw new AccessDenied('Token is expired');
   } else {
     res.locals.accessToken = object;
-    console.debug('AccessToken fetched', object);
+    req.oauth2.logger.debug('AccessToken fetched', object);
     next();
   }
 });
diff --git a/src/model/error.ts b/src/model/error.ts
index 0e2cb0e..6ba17c3 100644
--- a/src/model/error.ts
+++ b/src/model/error.ts
@@ -2,8 +2,12 @@ export class OAuth2Error extends Error {
   public name = 'OAuth2AbstractError';
   public logLevel = 'error';
 
-  constructor (public code: string, public message: string, public status: number) {
-    super()
+  constructor(
+    public code: string,
+    public message: string,
+    public status: number
+  ) {
+    super();
     Error.captureStackTrace(this, this.constructor);
   }
 }
@@ -12,7 +16,7 @@ export class AccessDenied extends OAuth2Error {
   public name = 'OAuth2AccessDenied';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('access_denied', msg, 403);
   }
 }
@@ -21,7 +25,7 @@ export class InvalidClient extends OAuth2Error {
   public name = 'OAuth2InvalidClient';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('invalid_client', msg, 401);
   }
 }
@@ -30,7 +34,7 @@ export class InvalidGrant extends OAuth2Error {
   public name = 'OAuth2InvalidGrant';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('invalid_grant', msg, 400);
   }
 }
@@ -39,7 +43,7 @@ export class InvalidRequest extends OAuth2Error {
   public name = 'OAuth2InvalidRequest';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('invalid_request', msg, 400);
   }
 }
@@ -48,7 +52,7 @@ export class InvalidScope extends OAuth2Error {
   public name = 'OAuth2InvalidScope';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('invalid_scope', msg, 400);
   }
 }
@@ -57,7 +61,7 @@ export class ServerError extends OAuth2Error {
   public name = 'OAuth2ServerError';
   public logLevel = 'error';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('server_error', msg, 500);
   }
 }
@@ -66,7 +70,7 @@ export class UnauthorizedClient extends OAuth2Error {
   public name = 'OAuth2UnauthorizedClient';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('unauthorized_client', msg, 400);
   }
 }
@@ -75,7 +79,7 @@ export class UnsupportedGrantType extends OAuth2Error {
   public name = 'OAuth2UnsupportedGrantType';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('unsupported_grant_type', msg, 400);
   }
 }
@@ -84,7 +88,7 @@ export class UnsupportedResponseType extends OAuth2Error {
   public name = 'OAuth2UnsupportedResponseType';
   public logLevel = 'info';
 
-  constructor (msg: string) {
+  constructor(msg: string) {
     super('unsupported_response_type', msg, 400);
   }
 }
diff --git a/src/model/model.ts b/src/model/model.ts
index 6c9a391..ddbe952 100644
--- a/src/model/model.ts
+++ b/src/model/model.ts
@@ -1,4 +1,5 @@
 import { Request, Response } from 'express';
+import { OAuth2Logger } from '../utils/logger';
 
 /**
  * OAuth2 client object
@@ -11,7 +12,7 @@ export interface OAuth2Client {
 }
 
 /**
- * OAuth2 access token object 
+ * OAuth2 access token object
  */
 export interface OAuth2AccessToken {
   token: string;
@@ -33,7 +34,7 @@ export interface OAuth2Code {
 }
 
 /**
- * OAuth2 refresh token object 
+ * OAuth2 refresh token object
  */
 export interface OAuth2RefreshToken {
   token: string;
@@ -46,7 +47,6 @@ export interface OAuth2RefreshToken {
  * OAuth2 implicit user model
  */
 export interface OAuth2User {
-  id: string | number;
   username: string;
   password: string;
 }
@@ -55,6 +55,7 @@ export interface OAuth2User {
  * OAuth2 token response
  */
 export interface OAuth2TokenResponse {
+  id_token?: string;
   access_token?: string;
   refresh_token?: string;
   expires_in?: number;
@@ -89,7 +90,9 @@ export interface OAuth2AccessTokenAdapter {
   /**
    * Fetch an access token by the token string from the database
    */
-  fetchByToken: (token: OAuth2AccessToken | string) => Promise<OAuth2AccessToken>;
+  fetchByToken: (
+    token: OAuth2AccessToken | string
+  ) => Promise<OAuth2AccessToken>;
 
   /**
    * Check the time-to-live value
@@ -163,7 +166,7 @@ export interface OAuth2CodeAdapter {
    * Static time-to-live in seconds for code
    */
   ttl: number;
-  
+
   /**
    * Create a new code
    */
@@ -209,6 +212,11 @@ export interface OAuth2CodeAdapter {
  * OAuth2 refresh token adapter model
  */
 export interface OAuth2RefreshTokenAdapter {
+  /**
+   * Invalidate all previous refresh tokens for user/client when new one is issued.
+   */
+  invalidateOld: boolean;
+
   /**
    * Create a new refresh token
    */
@@ -217,12 +225,14 @@ export interface OAuth2RefreshTokenAdapter {
     clientId: string | number,
     scope: string | string[]
   ) => Promise<string>;
-  
+
   /**
    * Fetch a token from the database
    */
-  fetchByToken: (token: OAuth2RefreshToken | string) => Promise<OAuth2RefreshToken>;
-  
+  fetchByToken: (
+    token: OAuth2RefreshToken | string
+  ) => Promise<OAuth2RefreshToken>;
+
   /**
    * Remove refresh token by user ID and client ID
    */
@@ -230,22 +240,22 @@ export interface OAuth2RefreshTokenAdapter {
     userId: string | number,
     clientId: string | number
   ) => Promise<boolean>;
-  
+
   /**
    * Remove token by the token itself
    */
   removeByRefreshToken: (token: string) => Promise<boolean>;
-  
+
   /**
    * Get user ID from token
    */
   getUserId: (code: OAuth2RefreshToken) => string;
-  
+
   /**
    * Get client ID from token
    */
   getClientId: (code: OAuth2RefreshToken) => string;
-  
+
   /**
    * Get scope from token
    */
@@ -276,7 +286,7 @@ export interface OAuth2UserAdapter {
    */
   checkPassword: (user: OAuth2User, password: string) => Promise<boolean>;
 
-  /** 
+  /**
    * Fetch the user from the express request
    */
   fetchFromRequest: (req: Request) => Promise<OAuth2User>;
@@ -300,6 +310,25 @@ export interface OAuth2UserAdapter {
   ) => Promise<boolean>;
 }
 
+/**
+ * Adapter for managing the `openid` scope.
+ */
+export interface JWTAdapter {
+  /**
+   * Issue a new ID token for user.
+   */
+  issueIdToken: (
+    user: OAuth2User,
+    scope: string[],
+    accessToken?: string
+  ) => Promise<string>;
+
+  /**
+   * Validate an ID token
+   */
+  validateIdToken: (idToken: string) => Promise<boolean>;
+}
+
 /**
  * Render the OAuth2 decision page
  */
@@ -321,6 +350,7 @@ export interface OAuth2AdapterModel {
   user: OAuth2UserAdapter;
   client: OAuth2ClientAdapter;
   code: OAuth2CodeAdapter;
+  jwt?: JWTAdapter;
 }
 
 /**
@@ -328,5 +358,6 @@ export interface OAuth2AdapterModel {
  */
 export interface OAuth2 {
   model: OAuth2AdapterModel;
+  logger: OAuth2Logger;
   decision: RenderOAuth2Decision;
 }
diff --git a/src/provider.ts b/src/provider.ts
index 6796dc2..64d3078 100644
--- a/src/provider.ts
+++ b/src/provider.ts
@@ -1,22 +1,28 @@
 import { RequestHandler } from 'express';
 import * as controller from './controller';
 import { middleware } from './middleware';
-import { RenderOAuth2Decision, OAuth2, OAuth2AdapterModel } from './model/model';
+import {
+  RenderOAuth2Decision,
+  OAuth2,
+  OAuth2AdapterModel,
+} from './model/model';
+import { OAuth2Logger } from './utils/logger';
 
 export class OAuth2Provider implements OAuth2 {
   public bearer = middleware;
   public controller = controller;
+  public logger = new OAuth2Logger('info');
 
-  constructor (
+  constructor(
     public model: OAuth2AdapterModel,
-    public decision: RenderOAuth2Decision,
+    public decision: RenderOAuth2Decision
   ) {}
 
   express(): RequestHandler {
     return (req, _res, next) => {
-      console.debug('OAuth2 Injected into request');
+      req.oauth2.logger.debug('OAuth2 Injected into request');
       req.oauth2 = this;
       next();
-    }
+    };
   }
 }
diff --git a/src/utils/logger.ts b/src/utils/logger.ts
new file mode 100644
index 0000000..cfd5fe7
--- /dev/null
+++ b/src/utils/logger.ts
@@ -0,0 +1,43 @@
+export type LoggerLevel = 'none' | 'info' | 'warn' | 'error' | 'debug';
+type LoggerFunction = (...args: any[]) => void;
+
+const LOG_LEVELS = ['none', 'info', 'warn', 'error', 'debug'];
+
+interface LoggerType {
+  info: LoggerFunction;
+  warn: LoggerFunction;
+  error: LoggerFunction;
+  debug: LoggerFunction;
+}
+
+export class OAuth2Logger {
+  constructor(
+    public logLevel: LoggerLevel,
+    public logger: LoggerType | undefined = console
+  ) {}
+
+  public setLogLevel(logLevel: LoggerLevel): void {
+    this.logLevel = logLevel;
+  }
+
+  public setLogger(logger?: LoggerType): void {
+    this.logger = logger;
+  }
+
+  public log(level: LoggerLevel, ...args: any[]): void {
+    if (!this.logger || this.logLevel === 'none') {
+      return;
+    }
+
+    if (LOG_LEVELS.indexOf(this.logLevel) < LOG_LEVELS.indexOf(level)) {
+      return;
+    }
+
+    this.logger[level as 'info' | 'warn' | 'error' | 'debug'](...args);
+  }
+
+  public info = this.log.bind(this, 'info');
+  public warn = this.log.bind(this, 'warn');
+  public error = this.log.bind(this, 'error');
+  public debug = this.log.bind(this, 'debug');
+}
diff --git a/src/utils/response.ts b/src/utils/response.ts
index 831b493..2ba5889 100644
--- a/src/utils/response.ts
+++ b/src/utils/response.ts
@@ -13,40 +13,49 @@ function dataRes(req: Request, res: Response, code: number, data: any): void {
   res.header('Cache-Control', 'no-store');
   res.header('Pragma', 'no-cache');
   res.status(code).send(data);
-  console.debug('Response:', data);
+  req.oauth2.logger.debug('Response:', data);
 }
 
 function redirect(req: Request, res: Response, redirectUri: string): void {
   res.header('Location', redirectUri);
   res.status(302).end();
-  console.debug('Redirecting to', redirectUri);
+  req.oauth2.logger.debug('Redirecting to', redirectUri);
 }
 
-export function error(req: Request, res: Response, err: OAuth2Error, redirectUri?: string): void {
+export function error(
+  req: Request,
+  res: Response,
+  err: OAuth2Error,
+  redirectUri?: string
+): void {
   // Transform unknown error
   if (!(err instanceof OAuth2Error)) {
-    console.error((err as Error).stack);
+    req.oauth2.logger.error((err as Error).stack);
     err = new ServerError('Uncaught exception');
   } else {
-    console.error('Exception caught', err.stack);
+    req.oauth2.logger.error('Exception caught', err.stack);
   }
 
   if (redirectUri) {
     const obj: ErrorResponseData = {
       error: err.code,
-      error_description: err.message
+      error_description: err.message,
     };
 
     if (req.query.state) {
       obj.state = req.query.state as string;
     }
 
-    redirectUri += '?' + (new URLSearchParams(obj as Record<string, string>).toString());
+    redirectUri +=
+      '?' + new URLSearchParams(obj as Record<string, string>).toString();
     redirect(req, res, redirectUri);
     return;
   }
 
-  dataRes(req, res, err.status, { error: err.code, error_description: err.message });
+  dataRes(req, res, err.status, {
+    error: err.code,
+    error_description: err.message,
+  });
 }
 
 export function data(
@@ -57,15 +66,15 @@ export function data(
   fragment: boolean = false
 ): void {
   if (redirectUri) {
-    redirectUri += fragment
-      ? '#'
-      : (redirectUri.indexOf('?') === -1 ? '?' : '&');
+    redirectUri += fragment ? '#' : redirectUri.indexOf('?') === -1 ? '?' : '&';
 
     if (req.query.state) {
       obj.state = req.query.state as string;
     }
 
-    redirectUri += new URLSearchParams(obj as Record<string, string>).toString();
+    redirectUri += new URLSearchParams(
+      obj as Record<string, string>
+    ).toString();
     redirect(req, res, redirectUri);
     return;
   }
diff --git a/src/utils/wrap.ts b/src/utils/wrap.ts
index 3326f31..b2a1d59 100644
--- a/src/utils/wrap.ts
+++ b/src/utils/wrap.ts
@@ -1,6 +1,8 @@
 import { RequestHandler } from 'express';
 import { error } from './response';
 
-export default (fn: RequestHandler, redir?: boolean): RequestHandler => (req, res, next) =>
-  (fn(req, res, next) as unknown as Promise<void>).catch(e =>
-    error(req, res, e, redir ? (req.query.redirect_uri as string) : undefined));
+export default (fn: RequestHandler, redir?: boolean): RequestHandler =>
+  (req, res, next) =>
+    (fn(req, res, next) as unknown as Promise<void>).catch((e) =>
+      error(req, res, e, redir ? (req.query.redirect_uri as string) : undefined)
+    );