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

# MLink Subscribe

| Field Name      | Field Type   | Description                                                                                                                                                                          |
| --------------- | ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| sessionID       | short        | (optional) actions below apply only to the sessionID virtual session; should be zero for non-multiplexed web-socket connections.                                                     |
| SubscribeID     | GroupingCode | (optional) subscribeD will be reflected back in the corresponding MLinkSubscribeAck message; nothing is assumed about structure of this number                                       |
| activeLatency   | int          | (optional) number of milliseconds between active send attempts (1 = minimum delay, 0 = wait for SignalReady) \[default = 0]                                                          |
| compression     | enum         | (optional) FieldChangesOnly will suppress fields in messages that have not changed since the previous send (resets automatically after every subscription) None=0,FieldChangesOnly=1 |
| doReset         | enum:YesNo   | if Yes all current subscriptions will be removed prior to applying the actions below                                                                                                 |
| `{View}`        |              |                                                                                                                                                                                      |
| msgName         | msgTypeName  | a SpiderRock message name (topic channel) (can be string name or protobuf message number)                                                                                            |
| view            | string       | list (subset) of field names to return with this message type (eg. bidprice or askprice or bidsize or asksize)                                                                       |
| `{Subscribe} `  |              |                                                                                                                                                                                      |
| msgName         | msgTypeName  | a SpiderRock message name (topic channel) (can be string name or protobuf message number)                                                                                            |
| msgPKey         | string       | an existing message.pkey; can be in either flat string or JSON format; if missing/empty all active msgName subscriptions will be removed                                             |
| `{Unsubscribe}` |              |                                                                                                                                                                                      |
| msgName         | msgTypeName  | a SpiderRock message name (topic channel) (can be string name or protobuf message number)                                                                                            |
| msgPKey         | string       | an existing message.pkey; can be in either flat string or JSON format; if missing/empty all active msgName subscriptions will be removed                                             |