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

# Connections

> Connections are configurations used in the Apinizer platform for API Proxies and API Integrator tasks to connect to external systems. They provide access to external resources such as databases, message queues, and email servers. Connections are defined once and can be used by multiple API Proxies or tasks. They are managed and updated centrally, and connection information is stored encrypted.

## Connection Features

A connection is a configuration containing information necessary to access an external system. Connections are defined once and can be used by multiple API Proxies or tasks.

<CardGroup cols={2}>
  <Card title="Reusable" icon="recycle">
    A connection can be used by multiple API Proxies or tasks
  </Card>

  <Card title="Centralized Management" icon="gear">
    Connections are managed and updated centrally
  </Card>

  <Card title="Security" icon="lock">
    Connection information is stored encrypted
  </Card>

  <Card title="Testable" icon="flask">
    Connections can be tested and validated
  </Card>
</CardGroup>

## Connection Usage Flow

The following diagram shows how connections are used by API Proxies and policies:

```mermaid theme={null}
sequenceDiagram
    participant Client as 👤 Client
    participant Gateway as 🚪 API Gateway
    participant Proxy as 🔀 API Proxy
    participant Policy as 🛡️ Policy/DB-2-API
    participant Connection as 🔌 Connection
    participant ExternalSystem as 🖥️ External System<br/>(DB, Kafka, Email, etc.)
    
    Client->>Gateway: HTTP Request
    
    Note over Gateway: Request Reached Gateway
    
    Gateway->>Proxy: Route Request to API Proxy
    
    Note over Proxy: API Proxy Processing
    
    Proxy->>Policy: Policy or DB-2-API<br/>Executed
    
    Note over Policy: External System Access Required
    
    Policy->>Connection: Connection Usage<br/>(Centralized Configuration)
    
    Note over Connection: Connection Information<br/>(Encrypted)<br/>Host, Port, Credentials
    
    Connection->>ExternalSystem: Secure Connection<br/>Established (SSL/TLS)
    
    Note over ExternalSystem: External System Types:<br/>Database (MongoDB, MySQL, etc.)<br/>Message Queue (Kafka, RabbitMQ)<br/>Email (SMTP)<br/>Search (Elasticsearch)
    
    ExternalSystem->>Connection: Operation Result<br/>Returns
    
    Connection->>Policy: Connection Result
    
    Policy->>Proxy: Policy Processing Completed
    
    Proxy->>Gateway: Processed Response
    
    Gateway->>Client: HTTP Response
    
    Note over Client,Gateway: Process Completed
    
    Note over Connection,ExternalSystem: Connection Pool<br/>Management and<br/>Reuse
```

## Connection Types

The Apinizer platform provides support for connections to a wide variety of external systems:

### Database Connections

<CardGroup cols={3}>
  <Card title="MongoDB" icon="database">
    MongoDB NoSQL database connections
  </Card>

  <Card title="MySQL" icon="database">
    MySQL database connections
  </Card>

  <Card title="PostgreSQL" icon="database">
    PostgreSQL database connections
  </Card>

  <Card title="Oracle" icon="database">
    Oracle database connections
  </Card>

  <Card title="MSSQL" icon="database">
    Microsoft SQL Server connections
  </Card>

  <Card title="DB2" icon="database">
    IBM DB2 connections
  </Card>

  <Card title="Sybase" icon="database">
    Sybase database connections
  </Card>

  <Card title="Apache Hive" icon="database">
    Apache Hive database connections
  </Card>

  <Card title="Apache Impala" icon="database">
    Apache Impala database connections
  </Card>

  <Card title="Trino" icon="database">
    Trino (PrestoSQL) database connections
  </Card>
</CardGroup>

### Message Queue Connections

<CardGroup cols={3}>
  <Card title="Kafka" icon="message">
    Apache Kafka connections
  </Card>

  <Card title="RabbitMQ" icon="message">
    RabbitMQ connections
  </Card>

  <Card title="ActiveMQ" icon="message">
    Apache ActiveMQ connections
  </Card>
</CardGroup>

### Search and Data Connections

<CardGroup cols={3}>
  <Card title="Elasticsearch" icon="magnifying-glass">
    Elasticsearch cluster connections
  </Card>

  <Card title="LDAP/AD" icon="users">
    LDAP/Active Directory connections
  </Card>

  <Card title="Webhook" icon="link">
    HTTP webhook connections
  </Card>
</CardGroup>

### Communication Connections

<CardGroup cols={3}>
  <Card title="SMTP/Email" icon="envelope">
    Email server connections
  </Card>

  <Card title="FTP/SFTP" icon="folder">
    FTP/SFTP server connections
  </Card>

  <Card title="Linux Script" icon="terminal">
    Linux script execution connections
  </Card>
</CardGroup>

### Logging and Monitoring Connections

<CardGroup cols={3}>
  <Card title="Graylog" icon="file-lines">
    Graylog GELF connections
  </Card>

  <Card title="Syslog" icon="file-lines">
    Syslog connections
  </Card>

  <Card title="Logback" icon="file-lines">
    Logback logging connections
  </Card>

  <Card title="SNMP" icon="network-wired">
    SNMP connections
  </Card>
</CardGroup>

## Connection Configuration

When creating a connection, the following information is defined:

<AccordionGroup>
  <Accordion title="Basic Information">
    * **Connection Name**: Unique name identifying the connection
    * **Connection Type**: Database, message queue, etc.
    * **Description**: Descriptive information about the connection (optional)
  </Accordion>

  <Accordion title="Connection Information">
    * **Host/URL**: Server address or connection URL
    * **Port**: Connection port (varies by connection type)
    * **Database Name**: Database name (for database connections)
  </Accordion>

  <Accordion title="Authentication">
    * **Username**: Username for the connection
    * **Password**: Password for the connection (stored encrypted)
    * **Credential Usage**: Whether credentials will be used
  </Accordion>

  <Accordion title="Advanced Settings">
    * **Connection Pool**: Connection pool settings (min/max pool size, etc.)
    * **Timeout**: Connection timeout settings
    * **SSL/TLS**: Secure connection settings
    * **Deploy to Worker**: Whether to deploy to Worker
    * **Enabled**: Whether the connection is active
  </Accordion>
</AccordionGroup>

## Connection Usage

Connections are used in the following situations:

<CardGroup cols={2}>
  <Card title="API Proxy" icon="server">
    **DB-2-API** can perform database queries

    SQL queries can be executed using database connections and results can be returned as API responses.
  </Card>

  <Card title="API Integrator" icon="diagram-project">
    Access to external systems is provided in **Task Flow**s

    Connections are used in Task Flows for operations such as database queries, message queue operations, and email sending.
  </Card>

  <Card title="Connectors" icon="puzzle-piece">
    Used for connectors to connect to external systems

    Connectors use connections to access different systems and exchange data.
  </Card>

  <Card title="Policies" icon="shield">
    Can be used for access to external systems within policies

    Some policies can communicate with external systems using connections.
  </Card>
</CardGroup>

## Connection Security

<Warning>
  **Important Security Notes:**

  * Connection information (username, password) is stored encrypted
  * Secure connections (SSL/TLS) must be used in production environments
  * Connection information is never written to log files
  * Connection information should be updated regularly
</Warning>

<Info>
  Since connections are managed centrally, when a connection's information changes, all API Proxies and tasks using this connection automatically use the updated information.
</Info>

## Connection Management

After connections are created:

* **Testable**: Connections can be tested and validated
* **Updatable**: Connection information can be updated
* **Deletable**: Connections that are no longer used can be deleted
* **Environment-Based**: Connections can be assigned to specific environments

<Tip>
  When creating connections, optimize connection pool settings according to your system load. Use low pool size for small systems and high pool size for high-traffic systems.
</Tip>

## Next Steps

<CardGroup cols={2}>
  <Card title="Connector" icon="puzzle-piece" href="/en/concepts/core-concepts/connector">
    Learn about the connector concept
  </Card>

  <Card title="Endpoint" icon="location-dot" href="/en/concepts/core-concepts/endpoint">
    Learn about the endpoint concept
  </Card>

  <Card title="Connection Management" icon="gear" href="/en/integrations/connection-management/overview">
    Connection management details
  </Card>

  <Card title="API Integrator" icon="diagram-project" href="/en/integrations/api-integrator-task-flow-builder/task-flow-design">
    API Integrator usage
  </Card>

  <Card title="DB-2-API" icon="database" href="/en/develop/api-proxy-creation/api-creator-db-api-creation">
    Database queries with DB-2-API
  </Card>
</CardGroup>