Getting Started with Relaycode

Welcome to Relaycode! This tutorial will guide you through building and submitting your first extrinsic on Polkadot.

What is Relaycode?

Relaycode is an extrinsic builder for the Polkadot ecosystem. It provides a user-friendly interface for:

Building extrinsics - Construct any pallet call using human-readable forms
Encoding/Decoding - Convert between form values and SCALE-encoded hex
Wallet integration - Connect your wallet to sign and submit transactions
Bi-directional editing - Edit via form or raw hex, with real-time sync

Prerequisites

A Polkadot-compatible wallet (Polkadot.js extension, Talisman, SubWallet, etc.)
Some DOT or testnet tokens for transaction fees

Selecting a Chain

Before connecting, choose which chain to interact with using the Chain Selector dropdown in the navbar:

Polkadot - Mainnet (DOT)
Kusama - Canary network (KSM)
Westend - Testnet (free test tokens, marked with "testnet" badge)

For your first time, we recommend selecting Westend so you can experiment without spending real tokens.

Connecting Your Wallet

Open Relaycode and navigate to the Builder page
Select your chain from the chain selector dropdown
Click "Connect" in the top navigation
Select your wallet from the available options (Polkadot.js, Talisman, or SubWallet)
Approve the connection in your wallet extension
Your connected accounts will appear in the Account selector

Once connected, you'll see your account balance and be able to select accounts for transactions.

Understanding the Interface

Relaycode uses a dual-pane interface:

Bidirectional editing in action

Left Pane (Form): Select pallets, methods, and fill in parameters using friendly input components.

Right Pane (Hex): See the resulting encoded call data in real-time. You can also paste hex to decode and edit.

Building Your First Extrinsic

Let's create a simple balance transfer:

Step 1: Select Pallet and Method

In the Pallet dropdown, search for and select "Balances"
In the Method dropdown, select "transferKeepAlive"

The form will update to show the required parameters.

Step 2: Fill in Parameters

The transfer requires two parameters:

dest (Destination)

Click the destination field
Select an account from your connected accounts, or
Paste an SS58 address, or
Select from recent addresses

value (Amount)

Enter the amount to transfer
Use the denomination selector (DOT, mDOT, planck)
Your available balance is shown below the input
Click "Max" to fill your maximum transferable amount

Step 3: Review the Encoded Call

As you fill in the form, the right pane updates with the encoded call data:

0x0503d43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d0700e8764817

This hex represents your complete extrinsic call:

05 - Balances pallet index
03 - transferKeepAlive method index
Remaining bytes - Encoded destination and amount

Step 4: Submit the Transaction

Review your transaction details
Click "Submit"
Your wallet will prompt you to sign
Approve the transaction in your wallet
Wait for confirmation

You'll see a success message with the transaction hash once it's included in a block.

Relaycode provides specialized inputs for every Substrate type. Instead of generic text fields, you get purpose-built components: account inputs with wallet integration and identicons, balance inputs with denomination switching, nested call builders for batch transactions, and more.

See the Component Library for the full list of 22 input components and 10 contextual selectors.