Hey so I was running a local node and trying explorer/polkadot.js-scripts to submit some extrinsic and from what I have seen from the data log, I have seen that something is being appended before the original data. Like I have seen that its scale enocoded and the length of vector is there, but there's more to it! Not sure what all being inside the extrinsic struct. I have got a struct from gsrpc extrinsic struct. I don't know if this is what I'm looking for. So can I have some reference on what struct of extrinsic is being used in polkadot-js or what is being added to the original data.

  • Could be double scale encoded?
    – Squirrel
    Commented Jun 10, 2022 at 16:00

1 Answer 1


Here is a previous answer with a full breakdown of an extrinsic.

Additionally you can also paste encoded data into the apps UI, and decode it into the parts to see what goes where (encoding details pane on the bottom right). Here is an example of a recent transfer on Polkadot.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.