1# Key Vault - SDK Patterns
2 
3## Node.js
4 
5> **Auth:** `DefaultAzureCredential` is for local development. See [auth-best-practices.md](../../auth-best-practices.md) for production patterns.
6 
7```javascript
8const { SecretClient } = require("@azure/keyvault-secrets");
9const { DefaultAzureCredential } = require("@azure/identity");
10 
11const client = new SecretClient(
12  process.env.KEY_VAULT_URL,
13  new DefaultAzureCredential()
14);
15 
16const secret = await client.getSecret("database-connection-string");
17console.log(secret.value);
18```
19 
20## Python
21 
22> **Auth:** `DefaultAzureCredential` is for local development. See [auth-best-practices.md](../../auth-best-practices.md) for production patterns.
23 
24```python
25from azure.keyvault.secrets import SecretClient
26from azure.identity import DefaultAzureCredential
27 
28client = SecretClient(
29    vault_url=os.environ["KEY_VAULT_URL"],
30    credential=DefaultAzureCredential()
31)
32 
33secret = client.get_secret("database-connection-string")
34print(secret.value)
35```
36 
37## .NET
38 
39> **Auth:** `DefaultAzureCredential` is for local development. See [auth-best-practices.md](../../auth-best-practices.md) for production patterns.
40 
41```csharp
42var client = new SecretClient(
43    new Uri(Environment.GetEnvironmentVariable("KEY_VAULT_URL")),
44    new DefaultAzureCredential()
45);
46 
47KeyVaultSecret secret = await client.GetSecretAsync("database-connection-string");
48Console.WriteLine(secret.Value);
49```
50 
51## Event Grid Integration (Expiry Notifications)
52 
53```bicep
54resource kvEventSubscription 'Microsoft.EventGrid/eventSubscriptions@2023-12-15-preview' = {
55  name: 'secret-expiry-notification'
56  scope: keyVault
57  properties: {
58    destination: {
59      endpointType: 'WebHook'
60      properties: {
61        endpointUrl: 'https://my-api.example.com/secret-rotation'
62      }
63    }
64    filter: {
65      includedEventTypes: [
66        'Microsoft.KeyVault.SecretNearExpiry'
67        'Microsoft.KeyVault.SecretExpired'
68      ]
69    }
70  }
71}
72```
73