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EVM on Testnet

This page covers how to set up your Metamask wallet to use with the testnet on Bittensor. You must run this step before you can run other tutorials in this section.

Key values:

  • The Bittensor Testnet URL: https://test.chain.opentensor.ai
  • EVM Subtensor Chain ID: 945 (UTF-8 encoded alpha character)
  • Opentensor EVM-Bittensor GitHub repo: https://github.com/opentensor/evm-bittensor/tree/main

Connect to EVM Testnet​

Confirm the EVM node is online and accessible. You can check the node status independently using curl or similar tools:

curl  -X POST \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}' \
  https://test.chain.opentensor.ai
{"jsonrpc":"2.0","id":1,"result":"0x460943"}

Create a Metamask wallet​

  1. If you don't already have it, install Metamask wallet browser extension.
  2. Create a new account.

Add testnet to Metamask​

Add the testnet to Metamask from within the Metamask wallet. Follow the below steps:

  1. Open Metamask Wallet extension on your browser. Click on the ⋮ (three vertical dots, i.e., vertical ellipsis) at the top right.
  2. Select Settings from the drop-down menu.
  3. Select Networks > Add network.
  4. Click on Add a network manually at the bottom of the networks list.
  5. Enter the following details:
    • Network name: "Subtensor"
    • EVM RPC URL: https://test.chain.opentensor.ai
    • Chain ID: 945
    • Currency symbol: TAO
  6. Click Save.
  7. Then click on Switch network.

With the above steps, you have successfully configured your Metamask wallet with the testnet.

Obtain TAO​

Next, request testnet TAO in the Bittensor community Discord.

Copy Metamask wallet private key into config​

In this step you will copy the private key from your Metamask wallet account and paste it into the configuration file in the repo. This step will ensure that you are not prompted with password each and every step as you run these tutorials.

  1. Navigate to the examples directory of the EVM-Bittensor repo:

    cd examples

  2. Create config.js file by copying the config-example.js file:

    cp config-example.js config.js

  3. On Metamask wallet extension, your wallet account will have a H160 account address, starting with the 0x prefix (for example: 0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf), and also your wallet account name.

  4. Click on your wallet account name, which will open the drop-down menu.

  5. Click on the ⋮ (three vertical dots, i.e., vertical ellipsis) next to the wallet account and select Account details. It will open a view with a QR code, your wallet account H160 address and a Show private key button.

  6. Click on the Show private key button, enter the password. You will then see the private key for your wallet account. Copy this private key.

  7. Paste this private key into ethPrivateKey string in your config.js file as shown below (mangled for security):

const ethPrivateKey = "02c1c4112233snipsnipsnipgh933aca491e090e0b7xxyy1b124b86d9382b01a8";

Save the config.js file. Now your setup is ready to run the tutorials with EVM testnet.