The Microsoft Graph API is a unified interface that provides access to Microsoft 365 services, including Office 365, Azure Active Directory (Azure AD), SharePoint, Teams, and more.

Its like the “one ring” - but in the cloud :)

Before Graph API existed, we had to code against with multiple APIs, each specific to a product like Exchange, SharePoint, or Active Directory.

This frankly sucked.. :)

The GraphAPI brought all these old APIS into one place..

🏛 The Early Days: APIs Before Graph API

Before Microsoft introduced Graph API, developers had to use separate APIs for different services:

The problem with this approach? Inconsistent authentication, different endpoints, and varied permissions for each API.

Microsoft needed a single API to unify these services.

🚀 The Birth of Microsoft Graph API (2015)

In November 2015, Microsoft introduced the Graph API as a RESTful, unified API for Microsoft cloud services.

Key Benefits of Graph API:
✅ One API for all Microsoft 365 services
✅ Consistent authentication using OAuth 2.0
✅ Access multiple services (Office, AD, Teams, OneDrive, etc.)
✅ Scalable and cloud-first design

Instead of querying Exchange, SharePoint, and Azure AD separately, developers could now use Graph API for everything.

🏢 How Microsoft Graph API Relates to Office 365

Office 365 is a cloud-based productivity suite that includes Word, Excel, Outlook, Teams, SharePoint, OneDrive, and more.

Graph API allows developers to integrate with Office 365 data and automate tasks:

Example: Retrieving Emails Using Graph API

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import requests

headers = {"Authorization": f"Bearer {token['access_token']}"}
response = requests.get("https://graph.microsoft.com/v1.0/me/messages", headers=headers)
print(response.json())

C# Example

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var response = await httpClient.GetAsync("https://graph.microsoft.com/v1.0/me/messages");
Console.WriteLine(await response.Content.ReadAsStringAsync());

🔐 How Microsoft Graph API Integrates with Azure Active Directory

Azure Active Directory (Azure AD) is Microsoft’s cloud-based identity and access management service. It controls authentication for Office 365, Azure, and enterprise applications.

How Graph API Works with Azure AD:

1. User Authentication – Uses OAuth 2.0 for secure logins.
2. User & Group Management – Manage users, groups, and permissions.
3. Security & Compliance – Retrieve audit logs, security alerts, and compliance reports.
4. Enterprise Apps – Integrate with third-party applications.

Example: Retrieving User Details from Azure AD

Python Example

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requests.get("https://graph.microsoft.com/v1.0/users", headers=headers)

C# Example

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await httpClient.GetAsync("https://graph.microsoft.com/v1.0/users");

Example: Managing Groups in Azure AD

Python Example

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requests.post("https://graph.microsoft.com/v1.0/groups", headers=headers, json={"displayName": "Developers", "mailNickname": "devs"})

C# Example

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var groupData = new { displayName = "Developers", mailNickname = "devs" };
var content = new StringContent(JsonConvert.SerializeObject(groupData), Encoding.UTF8, "application/json");
await httpClient.PostAsync("https://graph.microsoft.com/v1.0/groups", content);

📅 Key Milestones in the Evolution of Graph API

🔄 Transition from Legacy APIs to Graph API

Azure AD Graph API vs. Microsoft Graph API

• Azure AD Graph API was the original API for Active Directory.
• Microsoft Graph API replaced it with enhanced security, better performance, and more features.

Azure AD Graph API Deprecation Timeline:

• Deprecated in June 2023.
• Developers must migrate to Microsoft Graph API.

Exchange Web Services (EWS) vs. Graph API

• EWS was the old method to access emails and calendars.
• Graph API is now recommended for Outlook data.