diff --git a/package.json b/package.json
index 8556116..735e92d 100644
--- a/package.json
+++ b/package.json
@@ -28,5 +28,10 @@
     "gulp": "^3.9.1",
     "gulp-typescript": "^3.1.5",
     "typescript": "^2.2.1"
+  },
+  "dependencies": {
+    "inversify": "^3.1.0",
+    "randomstring": "^1.1.5",
+    "reflect-metadata": "^0.1.10"
   }
 }
diff --git a/source/FlowFactory.ts b/source/FlowFactory.ts
new file mode 100644
index 0000000..8f74771
--- /dev/null
+++ b/source/FlowFactory.ts
@@ -0,0 +1,48 @@
+import { IFlow } from './Flows/IFlow'
+
+type FlowTypeMap= {
+    type:string,
+    buildFunction:(data:any) => IFlow
+};
+
+/**
+ * Represents a factory that produce materialized instances of flows.
+ */
+class FlowFactory {
+  
+    private _flowTypeMapList:FlowTypeMap[];
+
+    /**
+     * Get a new flow instance builded with the given type and data.
+     * @param type Represents the type of flow to instantiate.
+     * @param data Represents the data to deserialize into the flow.
+     */
+    public getFlow(type:string, data:any):IFlow {
+        
+        let map:FlowTypeMap = this._flowTypeMapList.find(function(map:FlowTypeMap) { return map.type == type });
+
+        if (!map)
+            throw new Error('The type [' + type + '] dont have any asociated build function in the factory.');
+
+        return map.buildFunction(data);
+    }
+
+    /**
+     * Set the given build function as a builder for the given type. 
+     * @param type Represents the type to assing the builder function.
+     * @param buildFunction  Represents the function the build the flow of the given type.
+     */
+    public setFlowTypeBuilder(type:string,  buildFunction:(data:any) => IFlow):void {
+        
+        if (this._flowTypeMapList.find(function(map:FlowTypeMap) { return map.type == type }))
+            throw new Error('The type [' + type + '] already has a asociated build function in the factory.');
+        
+
+        this._flowTypeMapList.push({
+             type: type
+            ,buildFunction: buildFunction
+        });
+    }
+}
+
+export = new FlowFactory();
diff --git a/source/FlowResultBuilder.ts b/source/FlowResultBuilder.ts
new file mode 100644
index 0000000..ab793da
--- /dev/null
+++ b/source/FlowResultBuilder.ts
@@ -0,0 +1,36 @@
+import { FlowResult } from "./Models/FlowResult";
+import { IFlowResultBuilder } from "./IFlowResultBuilder";
+import { ITokenService } from "./Services/ITokenService";
+import { Token } from "./Models/Persistents/Token";
+
+/**
+ * Represents the a builder to vuild flows results.
+ */
+export class FlowResultBuilder implements IFlowResultBuilder {
+    
+    private _tokenService:ITokenService;
+    
+    /**
+     * Create a new instance of flow result builder.
+     * @param tokenService Represents a token service used to generate tokens.
+     */
+    constructor(tokenService:ITokenService) {
+        
+        this._tokenService = tokenService;
+    }
+
+    /**
+     * Return a builder FlowResult.
+     */
+    public async getResult():Promise<FlowResult> {
+        
+        let token:Token = await this._tokenService.generateToken();
+        let result:FlowResult = new FlowResult();                
+        
+        result.accessToken = token.value;
+        result.expireIn = token.expireIn;
+        result.refreshToken = token.refreshToken ? token.refreshToken.value : null;
+
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/AuthorizationCodeFlow.ts b/source/Flows/AuthorizationCodeFlow.ts
new file mode 100644
index 0000000..6002f07
--- /dev/null
+++ b/source/Flows/AuthorizationCodeFlow.ts
@@ -0,0 +1,30 @@
+import { ScopeBaseFlow } from './ScopeBaseFlow'
+import { IFlowHandler } from '../IFlowHandler'
+import { IClientService } from "../Services/IClientService";
+import { IFlowResultBuilder } from "../IFlowResultBuilder";
+
+/**
+ * Represents a authorization code flow.
+ */
+export class AuthorizationCodeFlow extends ScopeBaseFlow {
+
+    constructor(clientService:IClientService
+               ,flowResultBuilder:IFlowResultBuilder) {
+
+        super('authorization_code', clientService);
+    }  
+
+    /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     */
+    public async resolve(handler:IFlowHandler):Promise<boolean> {
+      
+        if (!super.resolve(handler) && await this._userService.validateCredentials(this.username, this.password)) {
+            handler.returnResult(await this._flowResultBuilder.getResult());
+        }
+        else
+            return false;
+
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/BaseFlow.ts b/source/Flows/BaseFlow.ts
new file mode 100644
index 0000000..987903a
--- /dev/null
+++ b/source/Flows/BaseFlow.ts
@@ -0,0 +1,72 @@
+import { IFlow } from './IFlow'
+import { IFlowHandler } from '../IFlowHandler'
+import { FlowError } from "../Models/FlowError";
+import { IClientService } from "../Services/IClientService";
+import { OAuthError } from "../OAuthError";
+
+/**
+ * Represents a base class for the oAuth flows.
+ */
+export abstract class BaseFlow implements IFlow {
+    /**
+     * Construct a new base flow [BaseFP] with the given type.
+     * @param type Represents the type of the flow processor.
+     */
+    constructor(type:string, clientService:IClientService) {
+        this._type = type;        
+    }
+
+    private _type:string;
+
+    /**
+     * Get the oAuth flow type.
+     */
+    get type() { return this._type;}
+
+    /**
+     * Get or set the client id with which the flow get the result.
+     */
+    public clientId: string;
+
+    /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     * @returns A boolean value specifying if the flow is reolved.
+     */
+    public async resolve(handler:IFlowHandler):Promise<boolean> {
+
+        let error:FlowError = await this.validate();
+
+        if (error) {
+            handler.notifyError(error);
+            return true; // I resolve it;
+        }
+        else
+            return false;  // I can not resolve it;
+    };
+
+    /**
+     * Execute the error resolution and handle it with the given handler.
+     * @param error Represents the error to resolve.
+     * @param handler Represents the handler.
+     * @returns A boolean value specifying if the error is reolved.
+     */
+    protected resolveError(error:Error, handler:IFlowHandler) {
+        if (error instanceof OAuthError) {
+
+            let oauthError:OAuthError = <OAuthError>error;
+
+            handler.notifyError(new FlowError(oauthError.code, oauthError.message));
+        }
+        else 
+            return false;                
+    }
+
+    /**
+     * Return a flow error instance when a error is founded in the evaluated flow.
+     * If return null no error was found.
+     */
+    protected async validate():Promise<FlowError> {
+        return null;
+    };
+}
\ No newline at end of file
diff --git a/source/Flows/ClientCredetialFlow.ts b/source/Flows/ClientCredetialFlow.ts
new file mode 100644
index 0000000..788d77b
--- /dev/null
+++ b/source/Flows/ClientCredetialFlow.ts
@@ -0,0 +1,55 @@
+import { BaseFlow } from './BaseFlow'
+import { IFlowHandler } from '../IFlowHandler'
+import { IClientService } from "../Services/IClientService";
+import { FlowResult } from "../Models/FlowResult";
+import { Token } from "../Models/Persistents/Token";
+import { ITokenService } from "../Services/ITokenService";
+import { IFlowResultBuilder } from "../IFlowResultBuilder";
+
+/**
+ * Represents a client credential flow.
+ */
+export class ClientCredetialFlow extends BaseFlow {
+
+    private _clientService:IClientService;
+    private _flowResultBuilder:IFlowResultBuilder;
+
+    /**
+     * Create ne instance of client credential flow.
+     * @param clientService Represents a client service to authenticate and validate the client.
+     * @param flowResultBuilder Represents a builder to build results.
+     */
+    constructor(clientService:IClientService
+               ,flowResultBuilder:IFlowResultBuilder) {
+
+        super('client_credential', clientService);
+
+        this._clientService = clientService;
+        this._flowResultBuilder = flowResultBuilder;
+    }
+
+    /**
+     * Get or set the client secret for the flow authentication.
+     */
+    public clientSecret:string;
+
+    /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     */
+    public async resolve(handler:IFlowHandler):Promise<boolean> {
+
+         if (!super.resolve(handler)) {
+            try {
+                await this._clientService.validateCredentials(this.clientId, this.clientSecret);
+                handler.returnResult(await this._flowResultBuilder.getResult());
+            }
+            catch(ex) {
+                if (!this.resolveError(ex, handler))
+                    throw ex;
+            }
+        }
+        else
+            return true; 
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/CodeExchangeFlow.ts b/source/Flows/CodeExchangeFlow.ts
new file mode 100644
index 0000000..f1c769d
--- /dev/null
+++ b/source/Flows/CodeExchangeFlow.ts
@@ -0,0 +1,35 @@
+import { BaseFlow } from './BaseFlow'
+import { IFlowHandler } from '../IFlowHandler'
+
+/**
+ * Represents a code exchange flow.
+ */
+export class CodeExchangeFlow extends BaseFlow {
+    constructor() {
+        super('code_exchange');
+    }
+
+    /**
+     * Get or set the code generated by the authorization code flow.
+     */
+    public code:string;
+
+    /**
+     * Get or set the redirection url used in the authorization code flow.
+     */
+    public redirectUri:string;
+
+   /**
+     * Get or set the client secret for the flow authentication.
+     */
+    public clientSecret:string;   
+
+    /**
+     * Execute the flow and handle it with the given handler.
+     * @param handler Represents the handler for the flow.
+     */
+    public execute(handler:IFlowHandler):void {  
+
+       
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/IFlow.ts b/source/Flows/IFlow.ts
new file mode 100644
index 0000000..d4a3a57
--- /dev/null
+++ b/source/Flows/IFlow.ts
@@ -0,0 +1,12 @@
+import { IFlowHandler } from '../IFlowHandler'
+
+/**
+ * Represents a oAuth flow.
+ */
+export interface IFlow {
+    /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     */
+    resolve(handler:IFlowHandler):Promise<boolean>;
+}
\ No newline at end of file
diff --git a/source/Flows/IFlowResultBuilder.ts b/source/Flows/IFlowResultBuilder.ts
new file mode 100644
index 0000000..ee0893e
--- /dev/null
+++ b/source/Flows/IFlowResultBuilder.ts
@@ -0,0 +1,11 @@
+import { FlowResult } from "./Models/FlowResult";
+
+/**
+ * Represents the a builder to vuild flows results.
+ */
+export interface IFlowResultBuilder {
+    /**
+     * Return a builder FlowResult.
+     */
+    getResult():Promise<FlowResult>
+}
\ No newline at end of file
diff --git a/source/Flows/ImplicitFlow.ts b/source/Flows/ImplicitFlow.ts
new file mode 100644
index 0000000..4a3ae0c
--- /dev/null
+++ b/source/Flows/ImplicitFlow.ts
@@ -0,0 +1,19 @@
+import { ScopeBaseFlow } from './ScopeBaseFlow'
+import { IFlowHandler } from '../IFlowHandler'
+
+/**
+ * Represents a implicit flow.
+ */
+export class AuthorizationCodeFlow extends ScopeBaseFlow {
+    constructor() {
+        super('implicit');
+    }  
+
+    /**
+     * Execute the flow and handle it with the given handler.
+     * @param handler Represents the handler for the flow.
+     */
+    public execute(handler:IFlowHandler):void { 
+               
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/PasswordFlow.ts b/source/Flows/PasswordFlow.ts
new file mode 100644
index 0000000..614322c
--- /dev/null
+++ b/source/Flows/PasswordFlow.ts
@@ -0,0 +1,67 @@
+import { BaseFlow } from './BaseFlow'
+import { FlowResult } from '../Models/FlowResult'
+import { IFlowHandler } from '../IFlowHandler'
+import { Token } from "../Models/Persistents/Token";
+import { ITokenService } from "../Services/ITokenService";
+import { IUserService } from "../Services/IUserService";
+import { FlowError } from "../Models/FlowError";
+import { IFlowResultBuilder } from "../IFlowResultBuilder";
+import { IClientService } from "../Services/IClientService";
+import { OAuthError } from "../OAuthError";
+
+
+/**
+ * Represents the password flow.
+ */
+export class PasswordFlow extends BaseFlow {
+
+    private _userService:IUserService;    
+    private _clientService:IClientService;
+    private _flowResultBuilder:IFlowResultBuilder;
+
+    /**
+     * Create a new instance of password flow class.
+     * @param userService Represents a user service used to authenticate the user. 
+     * @param clientService Represents a client service to perform some basic flow validations.
+     * @param flowResultBuilder Represents a builder to build results.
+     */
+    constructor(userService:IUserService               
+               ,clientService:IClientService
+               ,flowResultBuilder:IFlowResultBuilder) {
+
+        super('password', clientService);
+
+        this._userService = userService;
+        this._clientService = clientService;
+    }
+
+    /**
+     * Represents the user name to authenticate;
+     */
+    public username:string;
+    /**
+     * Represents the password of the user name to authenticate;
+     */
+    public password:string;
+
+     /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     */
+    public async resolve(handler:IFlowHandler):Promise<boolean> {
+      
+        if (!super.resolve(handler)) {
+            try {
+                await this._userService.validateCredentials(this.username, this.password);
+                handler.returnResult(await this._flowResultBuilder.getResult());
+            }
+            catch(ex) {
+                if (!this.resolveError(ex, handler))
+                    throw ex;
+            }
+        }
+        else
+            return true;
+
+    }
+}
\ No newline at end of file
diff --git a/source/Flows/ScopeBaseFlow.ts b/source/Flows/ScopeBaseFlow.ts
new file mode 100644
index 0000000..71ced8e
--- /dev/null
+++ b/source/Flows/ScopeBaseFlow.ts
@@ -0,0 +1,61 @@
+import { BaseFlow } from './BaseFlow'
+import { IFlowHandler } from '../IFlowHandler'
+import { IClientService } from "../Services/IClientService";
+import { FlowError } from "../Models/FlowError";
+
+/**
+ * Represents a base class for scoped based oAuth flows. 
+ */
+export abstract class ScopeBaseFlow extends BaseFlow {
+    constructor(type:string, clientService:IClientService) {
+        super(type, clientService);
+    }
+
+    /**
+     * Get or set the state to validate the authenticity when is compared with the result state.
+     */
+    public state:string;
+
+    /**
+     * Get or set the redirection url used in the authorization code flow.
+     */
+    public redirectUri:string;
+
+    /**
+     * Get or set the requested scopes.
+     */
+    public scopes:string[];
+
+    /**
+     * Execute the flow resolution and handle it with the given handler.
+     * @param handle Represents the handler.
+     */
+    public async resolve(handler:IFlowHandler):Promise<boolean> {
+
+        if (!super.resolve(handler))
+        {
+            let error:FlowError = await this.validate();   
+
+            if (error) {
+                handler.notifyError(error);
+                return true; // I resolve it;
+            }        
+        }
+
+        return false; // I can not resolve it;     
+    };
+
+    /**
+     * Return a flow error instance when a error is founded in the evaluated flow.
+     * If return null no error was found.
+     */
+    private async validate():Promise<FlowError> {
+
+        let error:FlowError = await super.validate();
+
+        if (error)
+            return error;
+
+        return null;
+    };
+}
\ No newline at end of file
diff --git a/source/IFlowHandler.ts b/source/IFlowHandler.ts
new file mode 100644
index 0000000..d2df008
--- /dev/null
+++ b/source/IFlowHandler.ts
@@ -0,0 +1,23 @@
+import { FlowResult } from './Models/FlowResult'
+import { FlowError } from "./Models/FlowError";
+
+/**
+ * Represents a handler for the flows.
+ */
+export interface IFlowHandler {
+    /**
+     * Redirect the request to another page, usually the authorization page.
+     * @param url Represents the url to redirect.
+     */
+    redirectToURL(url:string):void
+    /**
+     * Return the flow result to the requester client.
+     * @param result Represents the result to return.
+     */
+    returnResult(result:FlowResult):void
+    /**
+     * Notify an error that may occur.
+     * @param Represents the error that occur.
+     */
+    notifyError(error:FlowError):void
+}
\ No newline at end of file
diff --git a/source/IFlowResultBuilder.ts b/source/IFlowResultBuilder.ts
new file mode 100644
index 0000000..ee0893e
--- /dev/null
+++ b/source/IFlowResultBuilder.ts
@@ -0,0 +1,11 @@
+import { FlowResult } from "./Models/FlowResult";
+
+/**
+ * Represents the a builder to vuild flows results.
+ */
+export interface IFlowResultBuilder {
+    /**
+     * Return a builder FlowResult.
+     */
+    getResult():Promise<FlowResult>
+}
\ No newline at end of file
diff --git a/source/Models/FlowError.ts b/source/Models/FlowError.ts
new file mode 100644
index 0000000..11b0162
--- /dev/null
+++ b/source/Models/FlowError.ts
@@ -0,0 +1,28 @@
+/**
+ * Represents a error in a flow validation.
+ */
+export class FlowError {
+
+    private _code:string;
+    private _message:string;
+    
+    /**
+     * Create a new flow error instance with the given code and message.
+     * @param code 
+     * @param message 
+     */
+    constructor(code:string, message:string) {
+        this._code = code;
+        this._message = message;
+    }
+
+    /**
+     * Get the error code.
+     */
+    public get code() { return this._code; }
+
+    /**
+     * Get the error message.
+     */
+    public get message() { return this._message };
+}
\ No newline at end of file
diff --git a/source/Models/FlowResult.ts b/source/Models/FlowResult.ts
new file mode 100644
index 0000000..47cf552
--- /dev/null
+++ b/source/Models/FlowResult.ts
@@ -0,0 +1,21 @@
+/**
+ * Represents a result of a direct flow execution.
+ */
+export class FlowResult {
+    /**
+     * Represents the access token generated by the flow excecution.
+     */
+    public accessToken:string;
+    /**
+     * Represents the refresh token generated by the flow excecution.
+     */
+    public refreshToken:string;
+    /**
+     *Represents the time in which the access token will expire.
+     */
+    public expireIn:number;
+    /**
+     * Represents an state to validate the authenticity of the response result.
+     */
+    public state:string;
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/AuthorizationCode.ts b/source/Models/Persistents/AuthorizationCode.ts
new file mode 100644
index 0000000..b140735
--- /dev/null
+++ b/source/Models/Persistents/AuthorizationCode.ts
@@ -0,0 +1,32 @@
+import { Client } from "./Client";
+import { Token } from "./Token";
+
+/**
+ * Represents an authorization code.
+ */
+export class AuthorizationCode {
+    /**
+     * Get or set the code.
+     */
+    public code:string;
+
+    /**
+     * Get or set the client that generate the code.
+     */
+    public client:Client;
+
+    /**
+     * Get or set the state of the code.
+     */
+    public state:string;
+
+    /**
+     * Get or set the token generated with the coded;
+     */
+    public token:Token;
+
+    /**
+     * Get or set the date when the code was created.
+     */
+    public creationDate:Date;
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/BaseToken.ts b/source/Models/Persistents/BaseToken.ts
new file mode 100644
index 0000000..f27c84c
--- /dev/null
+++ b/source/Models/Persistents/BaseToken.ts
@@ -0,0 +1,20 @@
+/**
+ * Represents a base token.
+ */
+export abstract class BaseToken {
+    
+    /**
+     * Get or set the value of the token.
+     */
+    public value:string;
+
+    /**
+     * The time in seconds to the token expiration.
+     */
+    public expireIn:number;
+
+    /**
+     * Get or set the creation date.
+     */
+    public creationDate:Date;
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/Client.ts b/source/Models/Persistents/Client.ts
new file mode 100644
index 0000000..c08f780
--- /dev/null
+++ b/source/Models/Persistents/Client.ts
@@ -0,0 +1,19 @@
+/**
+ * Represents a client.
+ */
+export class Client {
+    /**
+     * Get or set the client id.
+     */
+    public clientId:string;
+
+    /**
+     * Get or set the client secret.
+     */
+    public clientSecret:string;
+
+    /**
+     * Get or set the redirect uri fro the client.
+     */
+    public redirectURI:string;
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/RefreshToken.ts b/source/Models/Persistents/RefreshToken.ts
new file mode 100644
index 0000000..ae53b57
--- /dev/null
+++ b/source/Models/Persistents/RefreshToken.ts
@@ -0,0 +1,8 @@
+import { BaseToken } from './BaseToken'
+
+/**
+ * Represents a refresh token.
+ */
+export class RefreshToken extends BaseToken {
+
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/Token.ts b/source/Models/Persistents/Token.ts
new file mode 100644
index 0000000..26aca86
--- /dev/null
+++ b/source/Models/Persistents/Token.ts
@@ -0,0 +1,18 @@
+import { BaseToken } from './BaseToken'
+import { Client } from "./Client";
+
+/**
+ * Represents a token.
+ */
+export class Token extends BaseToken {
+
+    /**
+     * Get or set the client that generate the token;
+     */
+    public client:Client;
+    
+    /**
+     * Get or set the refresh token information.
+     */
+    public refreshToken:BaseToken;
+}
\ No newline at end of file
diff --git a/source/Models/Persistents/User.ts b/source/Models/Persistents/User.ts
new file mode 100644
index 0000000..7beb4d4
--- /dev/null
+++ b/source/Models/Persistents/User.ts
@@ -0,0 +1,15 @@
+/**
+ * Represents an user.
+ */
+export class User {
+    
+    /**
+     * Get or set the user name.
+     */
+    public name:string;
+
+    /**
+     * Get or set the user password.
+     */
+    public password:string;
+}
\ No newline at end of file
diff --git a/source/OAuthContext.ts b/source/OAuthContext.ts
new file mode 100644
index 0000000..da94065
--- /dev/null
+++ b/source/OAuthContext.ts
@@ -0,0 +1,31 @@
+import { OAuthContextConfiguration } from './OAuthContextConfiguration'
+
+/**
+ * Represents an OAuth context.
+ */
+export class OAuthContext {
+
+    private _configuration:OAuthContextConfiguration;
+
+    /**
+     * Create a new instance of the OAuth context with a default configuration.
+     */
+    constructor() {
+        this.loadConfiguration();        
+    }
+
+    /**
+     * Get the context configuration.
+     */
+    public get configuration() { return this._configuration; }
+
+    private loadConfiguration() {
+        this._configuration = new OAuthContextConfiguration();
+        this._configuration.tokenExpirationTime = null;
+        this._configuration.refreshTokenExpirationTime = null;
+        this._configuration.authorizationCodeExpirationTime = 30;
+        this._configuration.mustGenerateRefreshToken = false;
+        this._configuration.tokenLength = 30;
+        this._configuration.authorizationCodeLength = 10;
+    }
+}
\ No newline at end of file
diff --git a/source/OAuthContextConfiguration.ts b/source/OAuthContextConfiguration.ts
new file mode 100644
index 0000000..f2b2880
--- /dev/null
+++ b/source/OAuthContextConfiguration.ts
@@ -0,0 +1,35 @@
+/**
+ * Represents a set of configurations for an OAuth context;
+ */
+export class OAuthContextConfiguration {
+
+    /**
+     * Get or set the amount of time in second for a token to expire;
+     */
+    public tokenExpirationTime:number;
+
+    /**
+     * Get or set the amount of time in second for a refresh token to expire;
+     */
+    public refreshTokenExpirationTime:number;
+
+     /**
+     * Get or set the amount of time in second for an authorization code to expire;
+     */
+    public authorizationCodeExpirationTime:number;
+
+    /**
+     * Get or set a boolean value specifying if the token generation process must create an refresh token;
+     */
+    public mustGenerateRefreshToken:boolean;
+
+    /**
+     * Get or set the length of the generated tokens.
+     */
+    public tokenLength:number;
+
+    /**
+     * Get or set the length of the generated authorization codes.
+     */
+    public authorizationCodeLength:number;
+}
\ No newline at end of file
diff --git a/source/OAuthError.ts b/source/OAuthError.ts
new file mode 100644
index 0000000..4c4310c
--- /dev/null
+++ b/source/OAuthError.ts
@@ -0,0 +1,23 @@
+/**
+ * Represents an OAuth error.
+ */
+export class OAuthError extends Error {
+
+    private _code:string;
+
+    /**
+     * Create a new instance of OAuth error.
+     * @param code Represents the code of the error.
+     * @param message Represents the message of the error.
+     */
+    constructor(code:string, message:string) {
+        super(message);
+
+        this._code = code;
+    }
+
+    /**
+     * Get the code of the error.
+     */
+    public get code() { return this._code; };
+}
\ No newline at end of file
diff --git a/source/Repositories/IAuthorizationCodeRepository.ts b/source/Repositories/IAuthorizationCodeRepository.ts
new file mode 100644
index 0000000..0c88855
--- /dev/null
+++ b/source/Repositories/IAuthorizationCodeRepository.ts
@@ -0,0 +1,19 @@
+import { AuthorizationCode } from '../Models/Persistents/AuthorizationCode'
+
+/**
+ * Represents a authorization code repository to persists authorization codes.
+ */
+export interface IAuthorizationCodeRepository {
+
+    /**
+     * Returns an authorization code by the given code.
+     * @param code Represents the code to look for.
+     */
+    getByCode(code:string):Promise<AuthorizationCode>;
+
+    /**
+     * Save or update authorization code instances.
+     * @param authorization Represents the authorization code instance that will be saved or updated.
+     */
+    save(authorizationClient:AuthorizationCode):Promise<void>;
+}
\ No newline at end of file
diff --git a/source/Repositories/IClientRepository.ts b/source/Repositories/IClientRepository.ts
new file mode 100644
index 0000000..4ce4d7b
--- /dev/null
+++ b/source/Repositories/IClientRepository.ts
@@ -0,0 +1,12 @@
+import { Client } from '../Models/Persistents/Client'
+
+/**
+ * Represents a client repository to persists clients.
+ */
+export interface IClientRepository {
+    /**
+     * Return a client instance by the given client id.
+     * @param clientId Represents the id of the client to look for.
+     */
+    getById(clientId:string):Promise<Client>;
+}
\ No newline at end of file
diff --git a/source/Repositories/ITokenRepository.ts b/source/Repositories/ITokenRepository.ts
new file mode 100644
index 0000000..fd441c6
--- /dev/null
+++ b/source/Repositories/ITokenRepository.ts
@@ -0,0 +1,19 @@
+import { Token } from '../Models/Persistents/Token'
+
+/**
+ * Represents a token repository to persists tokens.
+ */
+export interface ITokenRepository { 
+
+    /**
+     * Returns a tokent instance by the given value.
+     * @param value Represents the value to look for.
+     */ 
+    getByValue(value:string):Promise<Token>;
+
+    /**
+     * Save or update the token instance;
+     * @param token The token instance to persist.
+     */
+    save(token:Token):Promise<void>;
+}
\ No newline at end of file
diff --git a/source/Repositories/IUserRepository.ts b/source/Repositories/IUserRepository.ts
new file mode 100644
index 0000000..2c2f8b5
--- /dev/null
+++ b/source/Repositories/IUserRepository.ts
@@ -0,0 +1,13 @@
+import { User } from '../Models/Persistents/User'
+
+/**
+ * Represents an user repository to persists users.
+ */
+export interface IUserRepository {
+    
+    /**
+     * Returns an user instance by a given name.
+     * @param username Represent the user name to look for.
+     */
+    getByName(username:string):Promise<User>;
+}
\ No newline at end of file
diff --git a/source/Services/AuthorizationCodeService.ts b/source/Services/AuthorizationCodeService.ts
new file mode 100644
index 0000000..694530f
--- /dev/null
+++ b/source/Services/AuthorizationCodeService.ts
@@ -0,0 +1,109 @@
+import { Client } from "../Models/Persistents/Client";
+import { AuthorizationCode } from "../Models/Persistents/AuthorizationCode";
+import { IAuthorizationCodeService } from "./IAuthorizationCodeService";
+import { IAuthorizationCodeRepository } from "../Repositories/IAuthorizationCodeRepository";
+import { ITokenRepository } from "../Repositories/ITokenRepository";
+import { Token } from "../Models/Persistents/Token";
+import { OAuthError } from "../OAuthError";
+import { IClientService } from "./IClientService";
+import { IClientRepository } from "../Repositories/IClientRepository";
+import { IIdentifierGenerationService } from "./IIdentifierGenerationService";
+
+/**
+ * Represents an authorization code service that can generate and validate codes.
+ */
+export class AuthorizationCodeService implements IAuthorizationCodeService {
+    
+    private _authorizarionCodeRepository:IAuthorizationCodeRepository;
+    private _tokenRepository:ITokenRepository;
+    private _clientService:IClientService;
+    private _clientRepository:IClientRepository;
+    private _identifierGenerationService:IIdentifierGenerationService;
+    
+    /**
+     * Creates a new instance of authorization code service.
+     * @param authorizarionCodeRepository Represents a repository to persist and consult authorization codes.
+     * @param tokenRepository Represents a repository to persist and consult tokens.
+     * @param clientService Represents a client service to validate the clients.
+     * @param clientRepository Represents a repository to persist and consult clients.
+     * @param identifierGenerationService Represents a identifier generation service to generate codes.
+     */
+    constructor(authorizarionCodeRepository:IAuthorizationCodeRepository
+               ,tokenRepository:ITokenRepository
+               ,clientService:IClientService
+               ,clientRepository:IClientRepository
+               ,identifierGenerationService:IIdentifierGenerationService) {
+
+                this._authorizarionCodeRepository = authorizarionCodeRepository;
+                this._tokenRepository = tokenRepository;
+                this._clientService = clientService;
+                this._clientRepository = clientRepository;
+                this._identifierGenerationService = identifierGenerationService;
+    }
+
+    /**
+     * Validate if the given code is valid based on the given client.
+     * @param code Represents the code to validate.
+     * @param client Represents a client instance to validate the code.
+     */
+    public async validateCode(code:string, client:Client):Promise<void> {
+        
+        let authorizationCode:AuthorizationCode = await this._authorizarionCodeRepository.getByCode(code);
+
+        if (!authorizationCode)
+            throw new OAuthError('TODO:PutCode', 'The provided authorization code do not exists');
+
+        if (!client)
+            throw new OAuthError('TODO:PutCode', 'A client must be provided.');
+        
+        this._clientService.validateCredentials(client.clientId, client.clientSecret);
+
+        if (client.clientId != authorizationCode.client.clientId)
+            throw new OAuthError('TODO:PutCode', 'The client is unauthorized to exhange the provided code.');
+    }
+
+    /**
+     * Returns an authorization code instance by the given code.
+     * @param clientId Represents the clientId that own the code.
+     * @param state Represents the state of the code.
+     */
+    public async generateCode(clientId:string, state:string = null):Promise<AuthorizationCode> {
+
+        let authorizationCode:AuthorizationCode = new AuthorizationCode();
+        let client:Client = await this._clientRepository.getById(clientId);
+
+        if (!client)
+            throw new OAuthError('TODO:PutCode', 'There is not a client with the provided client Id');
+        
+        authorizationCode.code = await this._identifierGenerationService.getAuthorizationCodeValue();
+        authorizationCode.client = client;
+        authorizationCode.creationDate = new Date();
+        authorizationCode.state = state;
+
+        await this._authorizarionCodeRepository.save(authorizationCode);
+
+        return authorizationCode;
+    }
+
+     /**
+     * Associate a token to an existing authorization code.
+     * @param code Represents the code of the authorization code which the token will be associated.
+     * @param token Represents the token that will be associated to the authorization code. 
+     */
+    public async associateToken(code: string, token: string): Promise<void> {
+
+        let authorizationCode:AuthorizationCode = await this._authorizarionCodeRepository.getByCode(code);
+
+        if (!authorizationCode)
+            throw new OAuthError('TODO:PutCode', 'The provided authorization code do not exists');
+
+        let tokenInstance:Token = await this._tokenRepository.getByValue(token);
+
+        if (!tokenInstance)
+            throw new Error('The provided token don exists, the association can not be performed.');
+
+        authorizationCode.token = tokenInstance;
+
+        this._authorizarionCodeRepository.save(authorizationCode);                
+    }
+}
\ No newline at end of file
diff --git a/source/Services/ClientService.ts b/source/Services/ClientService.ts
new file mode 100644
index 0000000..d12f805
--- /dev/null
+++ b/source/Services/ClientService.ts
@@ -0,0 +1,34 @@
+import { IClientRepository } from "../Repositories/IClientRepository";
+import { Client } from "../Models/Persistents/Client";
+import { IClientService } from "./IClientService";
+import { OAuthError } from "../OAuthError";
+
+/**
+ * Represents a client service.
+ */
+export class ClientService implements IClientService {
+
+    private _clientRepository:IClientRepository;
+
+    /**
+     * Create a new instance of client service.
+     * @param clientRepository Represents a client repository to consult clients.
+     */
+    constructor(clientRepository:IClientRepository) {
+        this._clientRepository = clientRepository;
+    }
+
+    /**
+     * Validate the credentials of the client.
+     * @param clientId Represents the id of the client to authenticate.
+     * @param clientSecret Represents the secret of the client to authenticate.
+     */
+    public async validateCredentials(clientId:string, clientSecret:string):Promise<void> {
+
+        let client:Client = await this._clientRepository.getById(clientId);
+
+        if (client && client.clientSecret === clientSecret) {
+            throw new OAuthError('TODO:PutCode', 'The provided client credentials are invalid.');
+        };
+    }
+}
\ No newline at end of file
diff --git a/source/Services/IAuthorizationCodeService.ts b/source/Services/IAuthorizationCodeService.ts
new file mode 100644
index 0000000..7b64d35
--- /dev/null
+++ b/source/Services/IAuthorizationCodeService.ts
@@ -0,0 +1,29 @@
+import { Client } from "../Models/Persistents/Client";
+import { AuthorizationCode } from "../Models/Persistents/AuthorizationCode";
+
+/**
+ * Represents an authorization code service that can generate and validate codes.
+ */
+export interface IAuthorizationCodeService {
+
+    /**
+     * Validate if the given code is valid based on the given client.
+     * @param code Represents the code to validate.
+     * @param client Represents a client instance to validate the code.
+     */
+    validateCode(code:string, client:Client):Promise<void>;
+
+    /**
+     * Returns an authorization code instance by the given code.
+     * @param clientId Represents the clientId that own the code.
+     * @param state Represents the state of the code.
+     */
+    generateCode(clientId:string, state:string):Promise<AuthorizationCode>;
+
+    /**
+     * Associate a token to an existing authorization code.
+     * @param code Represents the code of the authorization code which the token will be associated.
+     * @param token Represents the token that will be associated to the authorization code. 
+     */
+    associateToken(code:string, token:string):Promise<void>;
+}
\ No newline at end of file
diff --git a/source/Services/IClientService.ts b/source/Services/IClientService.ts
new file mode 100644
index 0000000..36e8f63
--- /dev/null
+++ b/source/Services/IClientService.ts
@@ -0,0 +1,13 @@
+/**
+ * Represents a client service.
+ */
+import { Client } from "../Models/Persistents/Client";
+
+export interface IClientService {
+    /**
+     * Validate the credentials of the client.
+     * @param clientId Represents the id of the client to authenticate.
+     * @param clientSecret Represents the secret of the client to authenticate.
+     */
+    validateCredentials(clientId:string, clientSecret:string):Promise<void>;
+}
\ No newline at end of file
diff --git a/source/Services/IIdentifierGenerationService.ts b/source/Services/IIdentifierGenerationService.ts
new file mode 100644
index 0000000..b93d461
--- /dev/null
+++ b/source/Services/IIdentifierGenerationService.ts
@@ -0,0 +1,15 @@
+/**
+ * Represents a token generation service to generate tokens.
+ */
+export interface IIdentifierGenerationService {
+
+    /**
+     * Returns a new ramdom token value;
+     */
+    getTokenValue():Promise<string>;
+
+    /**
+     * Returns a new ramdom authorization code value;
+     */
+    getAuthorizationCodeValue():Promise<string>;
+}
\ No newline at end of file
diff --git a/source/Services/ITokenService.ts b/source/Services/ITokenService.ts
new file mode 100644
index 0000000..adda849
--- /dev/null
+++ b/source/Services/ITokenService.ts
@@ -0,0 +1,18 @@
+import { Token } from '../Models/Persistents/Token'
+
+/**
+ * Represents a token service.
+ */
+export interface ITokenService {    
+
+    /**
+     * Returns a token intance by the given value.
+     * @param tokenValue Represents the token value to look for.
+     */
+    getByValue(tokenValue:string):Promise<Token>;
+
+    /**
+     * Returns a new generated token.
+     */
+    generateToken():Promise<Token>;    
+}
\ No newline at end of file
diff --git a/source/Services/IUserService.ts b/source/Services/IUserService.ts
new file mode 100644
index 0000000..521d725
--- /dev/null
+++ b/source/Services/IUserService.ts
@@ -0,0 +1,11 @@
+/**
+ * Represent an user service.
+ */
+export interface IUserService {
+    /**
+     * Validate the credentials of the user.
+     * @param username Represents the user name.
+     * @param password Represents the user password.
+     */ 
+    validateCredentials(username:string, password:string):Promise<void>;
+}
\ No newline at end of file
diff --git a/source/Services/IdentifierGenerationService.ts b/source/Services/IdentifierGenerationService.ts
new file mode 100644
index 0000000..f0ca892
--- /dev/null
+++ b/source/Services/IdentifierGenerationService.ts
@@ -0,0 +1,33 @@
+import randomstring = require("randomstring")
+import { OAuthContext } from "../OAuthContext";
+import { IIdentifierGenerationService } from "./IIdentifierGenerationService";
+
+/**
+ * Represents a identifier generation service to generate tokens and authorization codes.
+ */
+export class IdentifierGenerationService implements IIdentifierGenerationService {
+    
+    private _oAuthContext:OAuthContext;
+    
+    /**
+     * Create a new instance of the token generation service.
+     * @param oAuthContext Represents the OAuth context that containing the default configurations for common objects.
+     */
+    constructor(oAuthContext:OAuthContext) {
+        this._oAuthContext = oAuthContext;
+    }
+
+    /**
+     * Returns a new ramdom token value;
+     */
+    public async getTokenValue():Promise<string> {
+        return randomstring.generate(this._oAuthContext.configuration.tokenLength | 30);
+    }
+
+    /**
+     * Returns a new ramdom authorization code value;
+     */
+    public async getAuthorizationCodeValue(): Promise<string> {
+        return randomstring.generate(this._oAuthContext.configuration.authorizationCodeLength | 10);
+    }
+}
\ No newline at end of file
diff --git a/source/Services/TokenService.ts b/source/Services/TokenService.ts
new file mode 100644
index 0000000..330c130
--- /dev/null
+++ b/source/Services/TokenService.ts
@@ -0,0 +1,59 @@
+import { Token } from '../Models/Persistents/Token'
+import { ITokenService } from './ITokenService'
+import { ITokenRepository } from '../Repositories/ITokenRepository'
+import { OAuthContext } from '../OAuthContext'
+import { RefreshToken } from "../Models/Persistents/RefreshToken";
+import { IIdentifierGenerationService } from './IIdentifierGenerationService'
+
+/**
+ * Represents a token service.
+ */
+export class TokenService implements ITokenService {    
+
+    private _tokenRepository:ITokenRepository;
+    private _tokenGenerationService:IIdentifierGenerationService;
+    private _oAuthContext:OAuthContext;
+
+    /**
+     * Create a new instance of the token service.
+     * @param tokenRepository Represents the token repository to consult and persist tokens.
+     * @param tokenGenerationService Represents the token generation service to generate tokens values.
+     * @param oAuthContext Represents the OAuth context that containing the default configurations for common objects.
+     */    
+    constructor(tokenRepository:ITokenRepository
+               ,tokenGenerationService:IIdentifierGenerationService
+               ,oAuthContext:OAuthContext) {
+
+        this._tokenRepository = tokenRepository;
+        this._tokenGenerationService = tokenGenerationService;
+        this._oAuthContext = oAuthContext;
+    }
+
+    /**
+     * Returns a token intance by the given value.
+     * @param tokenValue Represents the token value to look for.
+     */
+    public async getByValue(tokenValue:string):Promise<Token> {
+        return await this._tokenRepository.getByValue(tokenValue);        
+    }
+
+    /**
+     * Returns a new generated token.
+     */
+    public async generateToken():Promise<Token> {
+
+        let newToken:Token = new Token(); 
+        newToken.value = await this._tokenGenerationService.getTokenValue();
+        newToken.expireIn = this._oAuthContext.configuration.tokenExpirationTime;
+
+        if (this._oAuthContext.configuration.mustGenerateRefreshToken) {
+            newToken.refreshToken = new RefreshToken();
+            newToken.refreshToken.value = await this._tokenGenerationService.getTokenValue();
+            newToken.refreshToken.expireIn = this._oAuthContext.configuration.refreshTokenExpirationTime;       
+        }
+        
+        await this._tokenRepository.save(newToken);
+
+        return newToken;
+    }    
+}
\ No newline at end of file
diff --git a/source/Services/UserService.ts b/source/Services/UserService.ts
new file mode 100644
index 0000000..2a8d664
--- /dev/null
+++ b/source/Services/UserService.ts
@@ -0,0 +1,34 @@
+import { User } from '../Models/Persistents/User'
+import { IUserService } from './IUserService'
+import { IUserRepository } from '../Repositories/IUserRepository'
+import { OAuthError } from "../OAuthError";
+
+/**
+ * Represent an user service.
+ */
+export class UserService implements IUserService {
+    
+    private _userRepository:IUserRepository;
+
+    /**
+     * Create a new instance of the user service with tha given repository.
+     * @param userRepository Represet the repository to interact with the data.
+     */
+    constructor(userRepository:IUserRepository) {
+        this._userRepository = userRepository;
+    }
+
+    /**
+     * Validate the credentials of the user.
+     * @param username Represents the user name.
+     * @param password Represents the user password.
+     */ 
+    public async validateCredentials(username: string, password: string): Promise<void> {
+        
+        let user:User = await this._userRepository.getByName(username);
+
+        if (user && user.password === password) {
+            throw new OAuthError('TODO:PutCode', 'The provided user credentials are invalid.');
+        }
+    }
+}
\ No newline at end of file
diff --git a/source/main.ts b/source/main.ts
index a13c6fa..fd40910 100644
--- a/source/main.ts
+++ b/source/main.ts
@@ -1,3 +1,4 @@
-export class Main {
-    
-}
\ No newline at end of file
+
+
+
+