Would be very helpful to be able to delete all orders for a given symbol with a single API call. Please consider.
That would be nice to have but the endpoint might be ambious with order id (though symbol and uuid never match 
One more question is what would be the situation where you have multiple orders for a symbol. Isn’t it typically one order at a time per symbol?
Good question, I very commonly have multiple limit orders open for a symbol, especially with exit orders. I believe this is pretty common practice among day traders. Most broker platforms have a single click to cancel all orders for a given symbol.
Here is a chart showing a series of single green entry arrows and multiple associated red exit arrows that are representative of this style:
If there is a breaking news situation, for example, and I want to quickly change my overall exit strategy, I might need to delete all the pending exit orders and replace them with a single order or with a completely different set of orders. Yes, this work can be done on the front end. However, since all of this can happen very quickly, it seems preferable that the endpoint does this work to eliminate some of the potential race conditions or other synchronization issues between placing an orders, having them acknowledged and cancelling them.