Microsoft Graph API
Microsoft Graph is the unified API gateway to all Microsoft 365 services — access Outlook mail/calendar, Teams messages, SharePoint, OneDrive, Azure AD users, and more through a single REST endpoint.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Azure AD OAuth with fine-grained permission scopes. Admin consent required for org-wide access. Conditional Access can enforce MFA for Graph access. Client secrets or certificates for app auth. FedRAMP, HIPAA authorized.
⚡ Reliability
Best When
Your enterprise runs Microsoft 365 and agents need to work with Outlook, Teams, SharePoint, or Azure AD users — Graph is the single entry point for the entire Microsoft ecosystem.
Avoid When
You're on Google Workspace — Microsoft Graph is M365-specific. Also avoid for non-Microsoft enterprise systems.
Use Cases
- • Agents reading and sending Outlook emails and managing calendar events for enterprise workflows
- • Building Teams bots and message agents using Graph's messaging APIs
- • Syncing Active Directory/Azure AD users and groups for identity management agents
- • Reading and writing SharePoint lists and files from document management agents
- • OneDrive file operations for document processing and storage in M365 environments
Not For
- • Google Workspace environments (use Google Workspace APIs instead)
- • Real-time high-throughput messaging at Kafka scale
- • Consumer Microsoft accounts without M365 Business/Enterprise subscription for advanced features
Interface
Authentication
Azure AD OAuth 2.0. Delegated permissions (on behalf of user) or Application permissions (daemon apps). Permissions are admin-consented at tenant level. MSAL library recommended. Conditional Access policies may require MFA.
Pricing
Graph API itself is free; access depends on M365 subscription level. Premium APIs (advanced security, identity protection) require E5 licensing.
Agent Metadata
Known Gotchas
- ⚠ Application permissions require tenant admin consent — cannot use Graph for org data without IT admin approval
- ⚠ Graph uses OData query language ($filter, $select, $expand) — learning curve for agents not familiar with OData
- ⚠ Throttling can be aggressive for daemon apps making many calls — Graph throttles per-resource, not just globally
- ⚠ Delta queries for change tracking are powerful but require storing deltaLink across agent sessions
- ⚠ Teams APIs have additional throttling and are rate-limited differently from Exchange APIs — both are under Graph but different limits
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Microsoft Graph API.
Scores are editorial opinions as of 2026-03-06.