diff --git a/README.md b/README.md
index d6f5811..67e53af 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,4 @@
-Sparta CLI
-======
+# Sparta CLI
 
 # Installation
 
@@ -9,7 +8,9 @@ $ yarn install
 ```
 
 # Usage
+
 <!-- usage -->
+
 ```sh-session
 $ npm install -g sparta
 $ sparta COMMAND
@@ -21,13 +22,17 @@ USAGE
   $ sparta COMMAND
 ...
 ```
+
 <!-- usagestop -->
+
 # Commands
+
 <!-- commands -->
-* [`sparta help [COMMAND]`](#sparta-help-command)
-* [`sparta init`](#sparta-init)
-* [`sparta sync`](#sparta-sync)
-* [`sparta today`](#sparta-today)
+
+- [`sparta help [COMMAND]`](#sparta-help-command)
+- [`sparta init`](#sparta-init)
+- [`sparta sync`](#sparta-sync)
+- [`sparta today`](#sparta-today)
 
 ## `sparta help [COMMAND]`
 
@@ -58,6 +63,11 @@ EXAMPLE
   $ sparta init
 ```
 
+There are two flags that are hidden from the help (because we don't want students to use them):
+
+- `--spartaURL="<url>"` will update the URL that will be called when talking to Sparta API.
+- `--force` or `-f` will recreate the exercises repository (deleting the previous folder, beware).
+
 ## `sparta sync`
 
 Updates all the courses for the past days
@@ -75,4 +85,5 @@ Downloads the exercises for the current day
 USAGE
   $ sparta today
 ```
+
 <!-- commandsstop -->
diff --git a/src/base.ts b/src/base.ts
index fd0d7d0..be0ff46 100644
--- a/src/base.ts
+++ b/src/base.ts
@@ -1,4 +1,4 @@
-import Command, { flags } from "@oclif/command";
+import Command from "@oclif/command";
 
 import { SpartaError } from "./services/errors/sparta-error";
 
diff --git a/src/commands/init.ts b/src/commands/init.ts
index 5d594ab..b108cdd 100644
--- a/src/commands/init.ts
+++ b/src/commands/init.ts
@@ -1,8 +1,9 @@
+import { flags } from "@oclif/command";
 import cli from "cli-ux";
 import * as emoji from "node-emoji";
 
 import Command from "../base";
-import { loadConfig, ConfigInput, writeConfig } from "../config/config";
+import { loadConfig, writeConfig } from "../config/config";
 import initInstuctions from "../instructions/init";
 import checkWorkspace from "../services/check-workspace";
 import initExercicesRepository from "../services/init-exercises-repository";
@@ -14,11 +15,20 @@ export default class Init extends Command {
 
   static examples = ["$ sparta init"];
 
+  static flags = {
+    force: flags.boolean({ char: "f", default: false, hidden: true }),
+    spartaURL: flags.string({
+      hidden: true,
+      default: "https://sparta.fewlines.dev",
+    }),
+  };
+
   async run(): Promise<void> {
     const configDir = this.config.configDir;
     const userInput = await getUserInput();
+    const { flags } = this.parse(Init);
 
-    writeConfig(configDir, userInput);
+    writeConfig(configDir, { ...userInput, spartaURL: flags.spartaURL });
 
     const config = loadConfig(configDir);
 
@@ -26,7 +36,7 @@ export default class Init extends Command {
     checkWorkspace(config);
 
     this.log(emoji.emojify(":robot_face: Initializing exercises repository"));
-    await initExercicesRepository(config);
+    await initExercicesRepository(config, flags.force);
 
     cli.action.start(
       emoji.emojify(":robot_face: Preparing the Sparta configuration"),
@@ -45,7 +55,10 @@ export default class Init extends Command {
   }
 }
 
-async function getUserInput(): Promise<ConfigInput> {
+async function getUserInput(): Promise<{
+  batchID: string;
+  sharedSecret: string;
+}> {
   const batchID = await cli.prompt("What is the ID of your batch ?");
   const sharedSecret = await cli.prompt("Enter the Sparta secret token", {
     type: "hide",
diff --git a/src/config/config.ts b/src/config/config.ts
index 063ff53..2769709 100644
--- a/src/config/config.ts
+++ b/src/config/config.ts
@@ -19,11 +19,13 @@ export interface Config {
   exercisesCacheDir: string;
   batchID: string;
   sharedSecret: string;
+  spartaURL: string;
 }
 
 export interface ConfigInput {
   batchID: string;
   sharedSecret: string;
+  spartaURL: string;
 }
 
 export function loadConfig(configDir: string): Config {
diff --git a/src/services/fetch-past-days-exercises-paths.ts b/src/services/fetch-past-days-exercises-paths.ts
index 53afb1b..18d1761 100644
--- a/src/services/fetch-past-days-exercises-paths.ts
+++ b/src/services/fetch-past-days-exercises-paths.ts
@@ -18,7 +18,11 @@ export default async function fetchPastDaysExercisesPaths(
   let calendar: Calendar;
 
   try {
-    calendar = await fetchCalendar(config.batchID, config.sharedSecret);
+    calendar = await fetchCalendar(
+      config.spartaURL,
+      config.batchID,
+      config.sharedSecret,
+    );
   } catch (error) {
     throw new CalendarFetchError(error.message);
   }
diff --git a/src/services/fetch-today-exercises-path.ts b/src/services/fetch-today-exercises-path.ts
index b889b0a..e2e70f1 100644
--- a/src/services/fetch-today-exercises-path.ts
+++ b/src/services/fetch-today-exercises-path.ts
@@ -28,7 +28,11 @@ export default async function fetchTodayExercisesPath(
   let calendar: Calendar;
 
   try {
-    calendar = await fetchCalendar(config.batchID, config.sharedSecret);
+    calendar = await fetchCalendar(
+      config.spartaURL,
+      config.batchID,
+      config.sharedSecret,
+    );
   } catch (error) {
     throw new CalendarFetchError(error.message);
   }
diff --git a/src/services/init-exercises-repository.ts b/src/services/init-exercises-repository.ts
index ca14b75..61c3025 100644
--- a/src/services/init-exercises-repository.ts
+++ b/src/services/init-exercises-repository.ts
@@ -19,11 +19,14 @@ export class ExercisesDirectoryExistsError extends SpartaError {
 
 export default async function initExercicesRepository(
   config: Config,
+  force = false,
 ): Promise<void> {
   const directory = config.exercisesDir;
 
-  if (fs.existsSync(directory)) {
+  if (fs.existsSync(directory) && !force) {
     throw new ExercisesDirectoryExistsError(directory);
+  } else if (force) {
+    fs.removeSync(directory);
   }
 
   fs.ensureDirSync(directory);
diff --git a/src/services/update-today-exercises-directory.ts b/src/services/update-today-exercises-directory.ts
index 19e4067..e22da52 100644
--- a/src/services/update-today-exercises-directory.ts
+++ b/src/services/update-today-exercises-directory.ts
@@ -16,8 +16,10 @@ export default async function updateDayExercisesDirectory(
   const todayCurrentPath = path.join(exercisesDir, dayPath, "current");
   const todaySHAPath = path.join(exercisesDir, dayPath, directorySHA);
 
-  fs.ensureDirSync(todaySHAPath);
-  fs.copySync(todayCachePath, todaySHAPath);
-  fs.removeSync(todayCurrentPath);
-  fs.ensureSymlinkSync(todaySHAPath, todayCurrentPath);
+  if (!fs.existsSync(todaySHAPath)) {
+    fs.ensureDirSync(todaySHAPath);
+    fs.copySync(todayCachePath, todaySHAPath);
+    fs.removeSync(todayCurrentPath);
+    fs.ensureSymlinkSync(todaySHAPath, todayCurrentPath);
+  }
 }
diff --git a/src/utils/fetch-calendar.ts b/src/utils/fetch-calendar.ts
index 19f895a..c827130 100644
--- a/src/utils/fetch-calendar.ts
+++ b/src/utils/fetch-calendar.ts
@@ -3,17 +3,15 @@ import fetch from "node-fetch";
 import Calendar from "../models/calendar";
 
 export default async function fetchCalendar(
+  spartaURL: string,
   batchID: string,
   sharedSecret: string,
 ): Promise<Calendar> {
-  const response = await fetch(
-    `https://sparta.fewlines.dev/cli/calendar/${batchID}`,
-    {
-      headers: {
-        Authorization: `Bearer ${sharedSecret}`,
-      },
+  const response = await fetch(`${spartaURL}/cli/calendar/${batchID}`, {
+    headers: {
+      Authorization: `Bearer ${sharedSecret}`,
     },
-  );
+  });
 
   return response.json();
 }