I'm trying to get the regex crate to work on a pallet to check for an extrinsic input, but I can't get node to compile. Although I don't have the specific error to show, the question is if it is possible to include this crate in a pallet or how you can know which crates are compatible in a pallet.

  • What error do you get? Is it a no_std issue?
    – Simson
    Commented Nov 8, 2022 at 10:56
  • Can you post compilation error? and also your Cargo.toml code where you are adding this crate? Commented Nov 8, 2022 at 11:24
  • yes, I have to set it up again, that's why I was asking if it was possible without providing the error, but I'll attach it asap
    – andresvsm
    Commented Nov 8, 2022 at 11:34
  • 1
    You can not use regex in pallet btw. Please see my answer. I hope this helps. Commented Nov 8, 2022 at 11:39

1 Answer 1


All pallet dependencies should support no_std. regex does not support no_std.

You can use safe-regex as an alternative or any other dependency which supports no_std.

safe-regex = "0.2.5"

Add this in your Cargo.toml and it would work.

  • Thanks! I'll test it out. Where can I see wether a crate supports no_std or not? Should it have #![no_std] in the source?
    – andresvsm
    Commented Nov 8, 2022 at 11:48
  • I think so. safe-regex explicitly has mentioned in their document crates.io/crates/safe-regex Please accept the answer if this helps you. Commented Nov 8, 2022 at 11:52

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