Is it possible for a node to import mempool RPC without finishing IBD?

I’ve been digging into mempool lately and decided to try out some stuff on the mainnet mempool. But from what I found, the node has to finish the initial block download (IBD) up to the latest block before it can start populating the mempool. Right now, I’m really curious if my experiment can actually work. If it can, what’s the best way to get the info I need? I figure it’ll be a bit tricky based on what I’ve dealt with before, but I’m just wondering if there’s a way to use the importmempool RPC, which is like a link to the blockchain.

What are you trying to accomplish? You can't verify anything in an imported mempool without an up-to-date blockchain. I think you're going to have to wait for Bitcoin Core to complete syncing.

Never checked, but don't some of the block explorers have API calls for this? The issue is going to be with the mempool being well over 900MB that a lot of places / nodes are going to be dropping different transactions depending on their settings. I they have the default 300MB you may get a different answer then if they have it set to 512MB and that may be different then 1024MB. So unless you know what they are doing querying one will only get what they have in theirs. -Dave

I'm not aware of any "importmempool" command in Bitcoin Core, perhaps you're looking at some other Bitcoin node implementation? If so, please specify; While you're at it, please provide more information about your "experiment" so that users can give you more fitting answers.

Normally, your node won't download any unconfirmed transactions until reaching the chain tip, as it can't verify the validity of those transactions. If you want to know the current mempool of a random node, then just trust a block explorer? It has been requested, as you can see in this Bitcoin Core PR review, but it does a different thing; it loads transactions into your node's mempool given a mempool.dat.

Thanks, I see that it's just merged 3 weeks ago which will be included in the next release. I'm surprised that OP is using the dev build.