# Protocol APIs

You only need the page for the protocol your device actually speaks. Each of these injects one global
object into your script, on top of the [core API](../core_javascript_api/) that is always there.

{{% notice style="info" title="This is the reference, not the guide" icon="lightbulb" %}}
These pages document *which functions you can call*. For *how an integration over that protocol works* —
who opens the conversation, what the device must be, how to schedule the work — read
[Supported protocols](../../supported_protocols/), and then the page for your transport:
[HTTP](../../http/), [MQTT](../../mqtt/), [WebSocket](../../websocket/), [CoAP](../../coap/),
[Meter and industrial protocols](../../meter_protocols/) or [Remote access](../../remote_access/).
{{% /notice %}}

## Transports OpenGate already speaks

The device arrived over one of these, and the API lets you read the incoming message and shape the reply.

| Protocol | Object | Gives you |
|---|---|---|
| [HTTP](http/) | `http` | The received request, the response you return, and an HTTP client for outgoing calls |
| [MQTT](mqtt/) | `mqtt` | Publish messages to a topic |
| [WebSocket](websocket/) | — | Send a message down an already open connection |
| [CoAP](coap/) | `coap.server.response` | Set the status code, content format and body of the CoAP response. Integration: [CoAP](../../coap/) |

## Meter and industrial protocols

Here the connector function is the one that opens the conversation, usually to poll a meter.

| Protocol | Object | Gives you |
|---|---|---|
| [DLMS](dlms/) | `dlms` | Open a DLMS connection and run get, set and action requests |
| [DLMS Gas](dlms_gas/) | `dlms_gas` | Smart Gas meters across manufacturers, on top of DLMS |
| [IEC102](iec102/) | — | Connect over IEC102 and execute ASDUs: login, time, load curves, profiles |
| [SNMP](snmp/) | `snmp` | SNMP get and set against a device |

## Shell and network access

| Protocol | Object | Gives you |
|---|---|---|
| [SSH](ssh/) | `ssh` | Open a session, send commands, read the answer |
| [Telnet](telnet/) | — | The same over Telnet |
| [ICMP](icmp/) | — | Send a ping and process the result |
| [ICMP Response](icmp_response/) | `payload` | The payload a `RESPONSE` function receives with the ping result |

## Subscriptions

| Protocol | Object | Gives you |
|---|---|---|
| [Kite](kite/) | `kite` | Query and change a subscription's status through the Kite connector |

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