> For the complete documentation index, see [llms.txt](https://faq.finerymarkets.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faq.finerymarkets.com/api-reference/fix-api/market-data.md). # Market Data Every price or size values should be represented with FineryMarkets internal corresponding types. Description of all the types can be found [here](https://faq.finerymarkets.com/api-reference/data-types). ## Market Data Request\ Market data request allows the client to receive market data on a subscription basis.
TagNameRequiredExampleDescription
262MDReqIDY1Unique market data request Id
263SubscriptionRequestTypeY2Subscription request type(see below)
265MDUpdateTypeN1

Required if SubscriptionRequestType<263> is 1.

1 means incremental update.

267NoMDEntryTypesY2Number of MDEntryType <269> fields requested. Should always be 2 for bid and offer.
269=> MDEntryTypeY0Must be the first field in this repeating group. This is a list of all the types of Market Data Entries that the firm requesting the Market Data is interested in receiving (see below)
146NoRelatedSymY1Number of symbols (instruments) requested.
55=> SymbolYBTC-USDRequested instruments
| Subscription Request Type | Description | | :-----------------------: | :---------: | | 1 | Subscribe | | 2 | Unsubscribe | | MDEntryType | Description | | :---------: | :---------: | | 0 | Bid | | 1 | Offer | | MDUpdateType | Description | | :----------: | :-----------------: | | 1 | Incremental refresh | In case of successful subscription **Market Data - Snapshot/Full Refresh\** message sent to the client. Masters and makers will receive **Market Data - Snapshot/Full Refresh\** messages when the book changes. Takers will receive **Market Data - Incremental Refresh\** upon every book update. If subscription failed **Market Data Request Reject\** message sent to the client. Makers and Masters are subscribed to the [feed 'B'](/api-reference/websocket-api/feed-b-global-order-book.md). Takers are subscribed to the [feed 'F'](/api-reference/websocket-api/feed-f-firm-market-data.md). ## **Market Data - Snapshot/Full Refresh\** The Market Data messages are used as the response to a **Market Data Request\** message. In all cases, one Market Data message refers only to one **Market Data Request\** . Each Market Data message contains information about only one symbol(instrument).
TagNameRequiredExampleDescription
262MDReqIDY1Contains MDReqId<262> from corresponding Market Data Request
55SymbolYBTC-USDInstrument
268NoMDEntriesY1Number of entries following.
269=> MDEntryTypeY0Must be the first field of the repeating group. Entry type(see below)
270=> MDEntryPxY1Price, value of type Price
271=> MDEntrySizeY1Size, value of type Size
| MDEntryType | Description | | :---------: | :---------: | | 0 | Bid | | 1 | Offer | | J | Empty Book | ## **Market Data - Incremental Refresh\** The Market Data messages are used as the response to a **Market Data Request\** message. In all cases, one Market Data message refers only to one **Market Data Request\** . Contains incremental update for market data.
TagNameRequiredExampleDescription
262MDReqIDY1Contains MDReqId<262> from corresponding Market Data Request
268NoMDEntriesY1Number of entries following.
279=> MDUpdateActionY0Update Action(see below)
269=> MDEntryTypeY0Must be the first field of the repeating group. Entry type(see below)
55=> SymbolYBTC-USDInstrument
270=> MDEntryPxY1Price, value of type Price
271=> MDEntrySizeY1Size, value of type Size
| Update Action Code | Description | | :----------------: | :---------------------------------------------------------------------------------------------------------------------------------: | | 0 | New | | 1 | Change | | 2 | Delete | | 3 | Top of the book removed till specified price. Price and size of a new top level are returned (both zeros if book side became empty) | {% hint style="warning" %} If you receive tag <279>=3; <270>=12300000000; <271> =100000000, then you must delete levels from the existing order book starting from the top of the book and ending with the order at a price of 123 and size of 1. Therefore, price 123 and size 1 is the new top of the book If you receive the following update <279>=3; <270>=0; <271> =0, the described side of the book is empty. {% endhint %} | MDEntryType | Description | | :---------: | :---------: | | 0 | Bid | | 1 | Offer | | J | Empty Book | ## **Market Data - Reject \** The **Market Data Request Reject\** is used when FineryMarkets cannot honor the **Market Data Request\** , due to business or technical reasons.
TagNameRequiredExampleDescription
262MDReqIDY1Contains MDReqId<262> from corresponding Market Data Request
281MDReqRejReasonN0Rejection reason code(see below)
58TextN25Contains FM error code if MDReqRejReason<281> == F
| Rejection reason code | Description | | :-------------------: | :----------------------------------------------: | | 0 | Unknown symbol(instrument) | | 3 | Insufficient Permissions | | 4 | Unsupported SubscriptionRequestType <263> | | F | Finery Markets error, see code in Text<58> field | | A | Finery Markets error, see code in Text<58> field |