How to Get OneDrive Access Token: A Step-by-Step Guide

If you’re building an app or integration that connects with Microsoft OneDrive, you need to authenticate and securely access its APIs. That’s where an access token comes in. This guide will help you understand how to get a OneDrive access token, what is involved in OneDrive API authentication, and how to set up your OneDrive client ID, OAuth, and related configuration.

What is a OneDrive Access Token?

A OneDrive access token is like a digital key. Its access token is a temporary, secure string that your application uses to call the OneDrive API on behalf of a user. Without it, your app won’t be able to list files, upload, download, or make other API requests.

Access tokens are usually obtained through OAuth 2.0, a secure industry-standard protocol for authorization.

Step 1: Register Your Application (Get Client ID)

Before requesting a token, you need to register your app with Microsoft’s identity platform:

1. Go to Azure Portal → Azure Active Directory → App registrations.

2. Click “New registration”

3. Fill in the basic details:

   • Name of your app.

   • Supported account types (usually “Accounts in any organizational directory and personal Microsoft accounts” for consumer + business access).

   • Redirect URI (e.g., https://localhost for testing).

4. Click Register

   After registration, you’ll get:

   Client ID (used to identify your app)

   Directory (tenant) ID

   Optionally, you can generate a Client Secret for confidential flows.
   

Keep your Client ID safe. Never expose them in frontend code. This is essential for OAuth.

Step 2: Choose Your OneDrive API Authentication Flow

OneDrive supports several OAuth flows, depending on your app type:

• Authorization Code Flow: Most common, used by web apps.

• Client Credentials Flow: For apps running without user interaction (e.g., daemons).

• Implicit Flow: For browser-based or single-page apps.

For most use cases, Authorization Code Flow is recommended because it securely exchanges a code for an access token.

Step 3: Start OAuth Process (Request Authorization Code)

Redirect the user to the Microsoft authorization endpoint:

bash

https://login.microsoftonline.com/common/oauth2/v2.0/authorize

?client_id=YOUR_CLIENT_ID

&response_type=code

&redirect_uri=YOUR_REDIRECT_URI

&scope=files.readwrite offline_access

Here's what each part means:

• client_id: Your OneDrive client ID.

• response_type=code: Tells the server to return an authorization code.

• redirect_uri: Must match what you set in Azure.

• scope: Permissions your app needs (e.g., files.readwrite).

The user signs in and consents to the permissions. They are then redirected back to your app with a code parameter.

Step 4: Exchange Authorization Code for Access Token

Make a POST request to the token endpoint:

bash

POST https://login.microsoftonline.com/common/oauth2/v2.0/token

Content-Type: application/x-www-form-urlencoded

POST Body:

makefile

client_id=YOUR_CLIENT_ID

&scope=files.readwrite offline_access

&code=AUTHORIZATION_CODE

&redirect_uri=YOUR_REDIRECT_URI

&grant_type=authorization_code

&client_secret=YOUR_CLIENT_SECRET (if applicable)

The response will include:

• access_token (for OneDrive API calls)

• refresh_token (to get new tokens when the current one expires)

• expires_in (token lifetime, usually 1 hour)

Step 5: Use the Access Token in API Calls

Once you have the token, include the access_token in the Authorization header of your API calls:

http

GET https://graph.microsoft.com/v1.0/me/drive/root/children

Authorization: Bearer YOUR_ACCESS_TOKEN

Now your app can list files, upload, download, or make other calls using the token in OneDrive.

Step 6: Refresh the Access Token (When it Expires)

Access tokens usually expire in about an hour. But don't worry, you can use the refresh_token to get a new one:

bash

POST https://login.microsoftonline.com/common/oauth2/v2.0/token

POST Body:

makefile

client_id=YOUR_CLIENT_ID

&scope=files.readwrite offline_access

&refresh_token=YOUR_REFRESH_TOKEN

&grant_type=refresh_token

&client_secret=YOUR_CLIENT_SECRET (if applicable)

This gives you a new access token and refresh token, keeping your app running without needing to ask the user to log in again.

Tips for OneDrive OAuth and API Key Setup

• Don’t hardcode tokens in your code. Store them securely using key vaults or environment variables.

• Keep your client secret safe, never share it in frontend code.

• Use least privilege: request only the scopes your app needs.

• Test your flow thoroughly in development before going live.

What About OneDrive API Key?

Unlike some APIs, OneDrive doesn’t use a single API key. Instead, it relies on:

• Client ID

• Client Secret (if needed)

• Access token obtained through OAuth

This ensures that access is always authorized by the user and securely managed.

Conclusion

That’s it! You now know how to:

• Register an app and get your OneDrive client ID

• Implement OneDrive API authentication with OAuth

• Obtain and use a OneDrive access token

• Refresh tokens to keep your integration working

If you’d like to go deeper into permissions, scopes, and how Microsoft Graph handles authorization, explore our related blog: Authorization for OneDrive Graph API

Want Help with Microsoft API Integration?

At Cloud Science Labs, we help developers and businesses build secure and scalable integrations with Microsoft Graph, OneDrive, and other cloud services.

If you need help with implementing OAuth, handling tokens, or building secure APIs

From setting up secure access tokens to building end-to-end cloud integrations, our experts can help you get it right the first time.

Reach out at digital@cloudsciencelabs.com to simplify your next integration.