According to this documentation, the mempool can add transactions to the future queue. Is there a way to see this list programmatically (via rpc, api...) or manually (polkadotJs)? And do we know how long these transactions stay there and if there is a way to flush them?


To experiment, I sent a remark transaction with a higher nonce and examined the pending transactions:

let tx = await api.tx.system.remark(`Future queue test: ${senderNonce}`);
await tx.signAsync(sender, { nonce: senderNonce + 1, tip: 0, era: 64 });
await tx.send();

1 Answer 1


You can retrieve the pending transactions for any RPC node via the author_pendingExtrinsics call.

So your options are -

  • curl it (it will return the encoded extrinsics)
  • via JS or Python or any other APIs, just call the RPC and it will return the decoded versions
  • the information is visible in the polkadot-js apps UI as well via Explorer -> Node info
  • Thank you for the reply, but that endpoint only shows pending transactions not ones stored on the future queue. I did a simple experiment of sending a remark transaction with a higher sender nonce and none of those showed me the future queue transaction while i can see short lived pending transactions.
    – Nahu
    Jun 20, 2022 at 11:26
  • I can also see that after 64 blocks (mortality), these future transactions are removed, but I can't seem to find a way to "see" them in the meantime.
    – Nahu
    Jun 20, 2022 at 13:09

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