> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/supertokens/supertokens-core/llms.txt
> Use this file to discover all available pages before exploring further.

# Health Check

> GET /hello - Test SuperTokens Core server connectivity and health

## Overview

The `/hello` endpoint is a health check endpoint that verifies the SuperTokens Core server is running and can connect to the database. This endpoint is useful for monitoring, load balancers, and integration tests.

**Key Features:**

* No authentication required
* No API version header required
* Supports all HTTP methods (GET, POST, PUT, DELETE)
* Tests database connectivity
* Implements rate limiting (200 requests per window)
* App-specific (can be scoped to specific apps)

## Endpoint

```
GET /hello
POST /hello
PUT /hello
DELETE /hello
```

**Base URL:** `http://localhost:3567`

## Request

### Headers

No headers required. API key and version headers are optional and ignored.

### Query Parameters

None.

### Request Body

None.

## Response

### Success Response

**Status Code:** `200 OK`

**Content-Type:** `text/plain`

**Body:**

```
Hello
```

If the server is healthy and database connections are working, returns the plain text string `"Hello"`.

### Rate Limited Response

**Status Code:** `200 OK`

**Body (in testing mode):**

```
RateLimitedHello
```

When rate limited in testing mode, returns `"RateLimitedHello"`. In production mode, still returns `"Hello"` even when rate limited.

### Error Response

**Status Code:** `500 Internal Server Error`

If the server cannot connect to the database or a storage exception occurs, returns a 500 error with a ServletException.

## Examples

### cURL

```bash theme={null}
curl http://localhost:3567/hello
```

**Response:**

```
Hello
```

### App-Specific Request

```bash theme={null}
curl http://localhost:3567/appid-myapp/hello
```

### Tenant-Specific Request

```bash theme={null}
curl http://localhost:3567/tenant1/hello
```

### JavaScript (Node.js)

```javascript theme={null}
const response = await fetch('http://localhost:3567/hello');
const text = await response.text();
console.log(text); // "Hello"
```

### Python

```python theme={null}
import requests

response = requests.get('http://localhost:3567/hello')
print(response.text)  # "Hello"
```

## Implementation Details

### Rate Limiting

The endpoint implements rate limiting with a limit of 200 requests per window per app. The rate limiter is app-specific, so different apps have separate rate limits.

**Source**: [View source](https://github.com/supertokens/supertokens-core/blob/master/src/main/java/io/supertokens/webserver/api/core/HelloAPI.java#L89)

### Database Health Check

The endpoint tests database connectivity by calling `storage.getKeyValue()` on all storage instances for the app. This ensures that:

* The database connection is active
* All storage layers are responding
* The core can read from the database

**Source**: [View source](https://github.com/supertokens/supertokens-core/blob/master/src/main/java/io/supertokens/webserver/api/core/HelloAPI.java#L106-L110)

## Use Cases

### Health Monitoring

```bash theme={null}
#!/bin/bash
# Simple health check script
if curl -f http://localhost:3567/hello > /dev/null 2>&1; then
  echo "SuperTokens is healthy"
  exit 0
else
  echo "SuperTokens is down"
  exit 1
fi
```

### Docker Health Check

```dockerfile theme={null}
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:3567/hello || exit 1
```

### Kubernetes Liveness Probe

```yaml theme={null}
livenessProbe:
  httpGet:
    path: /hello
    port: 3567
  initialDelaySeconds: 10
  periodSeconds: 30
```

## Error Handling

<Warning>
  If the `/hello` endpoint returns a 500 error, check your database connection and storage configuration. This typically indicates a storage layer issue.
</Warning>

**Common Issues:**

* Database connection timeout
* Storage plugin not initialized
* Database credentials incorrect
* Network connectivity issues

## Notes

* This endpoint is also available at the root path `/` (see NotFoundOrHelloAPI)
* Rate limiting is transparent to the client - no error is returned
* The endpoint works across all HTTP methods for maximum compatibility
* No API key required makes it suitable for public health checks

## Related Endpoints

<CardGroup cols={2}>
  <Card title="Configuration" icon="gear" href="/api/core/config">
    Get server configuration details
  </Card>

  <Card title="API Overview" icon="book" href="/api/core/overview">
    Learn about authentication and error handling
  </Card>
</CardGroup>