This would be an old issue, but the solutions I have seen on this site aren't working. I'm trying to import a contract of OpenZeppelin to my Remix IDE.

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.4.0/contracts/token/ERC721/ERC721Full.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.4.0/contracts/drafts/Counters.sol";

And it gives me an error:

Unable to import "undefined": TypeError: Failed to fetch

enter image description here

  • I believe that you need to change this: Commented Apr 1, 2020 at 9:11
  • https://github.com/OpenZeppelin/openzeppelin-contracts/blob Commented Apr 1, 2020 at 9:11
  • To this: openzeppelin-contracts/tree Commented Apr 1, 2020 at 9:11
  • For sure you need to get rid of the https://github.com/ prefix. Commented Apr 1, 2020 at 9:12
  • @goodvibration: I'm sorry, not in that sense :) just need to know that you are suggesting in this way? import "openzeppelin-contracts/tree/contracts/token/ERC721/ERC721Full.sol";
    – Div
    Commented Apr 1, 2020 at 9:25

1 Answer 1


To import from a tag or branch use /blob/<tag>

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.4.0/contracts/math/SafeMath.sol";

It is not mentioned explicitly in the documentation https://remix-ide.readthedocs.io/en/latest/import.html but it works.

  • Thanks! the issue is weird, it is working fine as shown in the question, previously it was showing an error.
    – Div
    Commented Apr 2, 2020 at 3:43

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