Microsoft Graph API

Microsoft Graph API Skill

Comprehensive reference for Microsoft Graph API integration including endpoints, authentication, rate limiting, and best practices.

⚠️ Staleness Warning

Microsoft Graph APIs evolve frequently. Permissions, endpoints, and authentication flows may change. See EXTERNAL-API-REGISTRY.md for source URLs and recheck cadence.

Refresh triggers:

• Microsoft Graph API version updates
• MSAL library major releases
• Azure Active Directory to Microsoft Entra ID migration (completed)
• New Graph scopes or permissions

Last validated: February 2026 (Graph v1.0, MSAL 2.x)

Check current state: Graph Explorer, Graph API Reference

API Quick Reference

Base URLs

Best Practice: Use v1.0 for production. Beta endpoints can change without notice.

Authentication

Token Acquisition (VS Code Extension):

// Progressive scope acquisition — request minimal scopes initially
const INITIAL_SCOPES = ['User.Read'];
const FULL_SCOPES = [
    'User.Read',
    'Calendars.Read',
    'Mail.Read',
    'Presence.Read',
    'People.Read',
    'Group.Read.All'
];

async function getGraphToken(): Promise<string | null> {
    const session = await vscode.authentication.getSession(
        'microsoft',
        FULL_SCOPES,
        { createIfNone: false }
    );
    return session?.accessToken ?? null;
}

Permissions (Scopes) Reference

Common Delegated Scopes

Common Application Scopes

Principle of Least Privilege: Request only the scopes your app actually needs. Start with User.Read and add incrementally.

Key Endpoints by Service

Users

Mail

Calendar

Presence

People & Insights

SharePoint & OneDrive

Planner (Task Management)

Note: Planner only supports delegated permissions. Application permissions are not available.

To Do

Groups & Teams

Service Health & Communications (FishbowlGovernance pattern)

Rate limit: 1,500 requests / 10 minutes

Audit Logs (FishbowlGovernance pattern)

Rate limit: Security endpoints = 150 requests / 10 minutes

Sensitivity Labels (Information Protection)

Critical Patterns

Custom Error Types

export class GraphRateLimitError extends Error {
  public readonly retryAfter: number;

  constructor(retryAfter: number, message = '') {
    super(`Rate limited. Retry after ${retryAfter}s. ${message}`);
    this.name = 'GraphRateLimitError';
    this.retryAfter = retryAfter;
  }
}

export class GraphApiError extends Error {
  public readonly statusCode: number;
  public readonly errorCode: string;

  constructor(statusCode: number, errorCode: string, message: string) {
    super(`Graph API ${statusCode} (${errorCode}): ${message}`);
    this.name = 'GraphApiError';
    this.statusCode = statusCode;
    this.errorCode = errorCode;
  }
}

API Client Pattern (with retry + timeout)

const GRAPH_ENDPOINT = 'https://graph.microsoft.com/v1.0';
const DEFAULT_TIMEOUT_MS = 30000;
const DEFAULT_MAX_RETRIES = 3;

async function graphRequest<T>(
  method: 'GET' | 'POST' | 'PATCH' | 'DELETE',
  endpoint: string,
  options: RequestInit = {},
  config: { timeoutMs?: number; maxRetries?: number; throwOnError?: boolean } = {}
): Promise<T | null> {
    const token = await getGraphToken();
    if (!token) return null;

    const { timeoutMs = DEFAULT_TIMEOUT_MS, maxRetries = DEFAULT_MAX_RETRIES, throwOnError = false } = config;

    for (let attempt = 0; attempt <= maxRetries; attempt++) {
        const controller = new AbortController();
        const timeoutId = setTimeout(() => controller.abort(), timeoutMs);

        try {
            const response = await fetch(`${GRAPH_ENDPOINT}${endpoint}`, {
                method,
                ...options,
                signal: controller.signal,
                headers: { 'Authorization': `Bearer ${token}`, ...options.headers }
            });
            clearTimeout(timeoutId);

            // Handle 429 rate limiting
            if (response.status === 429) {
                const retryAfter = parseInt(response.headers.get('Retry-After') || '10');
                if (attempt < maxRetries) {
                    await new Promise(r => setTimeout(r, retryAfter * 1000));
                    continue;
                }
                if (throwOnError) throw new GraphRateLimitError(retryAfter);
                return null;
            }

            // Handle 5xx with exponential backoff
            if (response.status >= 500 && attempt < maxRetries) {
                await new Promise(r => setTimeout(r, Math.pow(2, attempt) * 1000));
                continue;
            }

            if (!response.ok) {
                if (throwOnError) {
                    const err = await response.json().catch(() => ({}));
                    throw new GraphApiError(response.status, err?.error?.code || 'Unknown', err?.error?.message || response.statusText);
                }
                return null;
            }

            return response.json();
        } catch (error) {
            clearTimeout(timeoutId);
            if (error instanceof Error && error.name === 'AbortError' && attempt < maxRetries) {
                await new Promise(r => setTimeout(r, Math.pow(2, attempt) * 1000));
                continue;
            }
            throw error;
        }
    }
    return null;
}

OData Query Parameters

Graph supports standard OData query parameters:

Combining parameters:

GET /users?$select=id,displayName,department&$filter=department eq 'Analytics'&$top=25&$orderby=displayName

Not all endpoints support all parameters. Check specific endpoint docs.

Pagination

Graph uses @odata.nextLink for pagination:

async function graphFetchAll<T>(path: string): Promise<T[]> {
    const token = await getGraphToken();
    if (!token) return [];
    
    const results: T[] = [];
    let url: string | null = `${GRAPH_ENDPOINT}${path}`;

    while (url) {
        const response = await fetch(url, {
            headers: { 'Authorization': `Bearer ${token}` }
        });
        const data = await response.json();
        results.push(...(data.value || []));
        url = data['@odata.nextLink'] || null;
    }

    return results;
}

JSON Batching

Combine up to 20 requests in a single HTTP call:

interface BatchRequest {
    id: string;
    method: 'GET' | 'POST' | 'PATCH' | 'DELETE';
    url: string;
    body?: unknown;
}

async function graphBatch<T>(requests: BatchRequest[]): Promise<Map<string, T>> {
    if (requests.length > 20) {
        console.warn('Batch limit is 20, use graphBatchAll() for unlimited');
        requests = requests.slice(0, 20);
    }

    const response = await graphPost<{ responses: Array<{ id: string; status: number; body: T }> }>(
        '/$batch',
        { requests }
    );

    const results = new Map<string, T>();
    for (const resp of response?.responses || []) {
        if (resp.status >= 200 && resp.status < 300) {
            results.set(resp.id, resp.body);
        }
    }
    return results;
}

// Auto-chunk unlimited requests into batches of 20
async function graphBatchAll<T>(requests: BatchRequest[]): Promise<Map<string, T>> {
    const allResults = new Map<string, T>();
    for (let i = 0; i < requests.length; i += 20) {
        const chunk = requests.slice(i, i + 20);
        const chunkResults = await graphBatch<T>(chunk);
        for (const [id, body] of chunkResults) {
            allResults.set(id, body);
        }
    }
    return allResults;
}

Helper: Build Batch Request

function buildBatchRequest(
    method: 'GET' | 'POST' | 'PATCH' | 'DELETE',
    url: string,
    body?: unknown,
    requestId?: string
): BatchRequest {
    return {
        id: requestId || Math.random().toString(36).substring(2, 10),
        method,
        url,
        body,
    };
}

Rate Limits & Throttling

Service-Specific Limits

Throttled Response

HTTP/1.1 429 Too Many Requests
Retry-After: 30

Best Practices for Avoiding Throttling

1. Use $select to request only needed properties
2. Use $filter server-side instead of fetching all and filtering locally
3. Use JSON batching to reduce request count
4. Implement exponential backoff with jitter
5. Cache responses where data doesn't change frequently

Token Lifetime

Always use MSAL rather than raw OAuth. MSAL handles caching, refresh, and retry automatically.

SDKs & Client Libraries

the AI assistant-Specific Integration Points

References

• Microsoft Graph Overview
• Graph Explorer
• Graph API Reference (v1.0)
• Permissions Reference
• Graph API Throttling
• MSAL Overview
• JSON Batching