Hi,
As per FIX specs, Quote (35=S) can be used to add firm or indicative interest to the book. In case an indicative quote is submitted, upon match, the venue will inquire the quote submitter whether its ok to proceed with the execution (last look conversation).
Similarly, can we use New Order -Single (35=D) message to send indicative interest so that upon match, the venue will inquire the indicative order submitter of the match?
If yes, what would be the message flow look like?
There is no short answer to this as there are many models to emulate such behavior with orders. Quotes and orders are very similar. One of the differences is that only quotes can be indicative. The quote can be followed up by an order referencing the quote to confirm the match. Another model is to use a second order to confirm a potential match (see also EP252). There are also IOI(35=6) messages to indicate interest.
@dnchamilka at an abstracted level what you described in your original post sounds like LSEG Turquoise Block Discovery workflow (https://www.lseg.com/test-tq-bd) which EP252 that Hanno mentioned addressed one aspect of it. Not clear to me how Turquoise conveys the “order submission request” to the two members whose “order” matched. Personally I am not a fan of using NewOrder as an “indicative indication” - it wasn’t the intent of that message type from the very beginning of FIX.