Asset Hub Migration: What Developers Need to Know About the Polkadot Relay Chain Transition

Asset Hub Migration Decision Checklist

Before the migration, review these key points to ensure your applications and infrastructure are ready:

What Is the Asset Hub Migration?

The Asset Hub migration is a phased upgrade that moves three core pallets—balances, staking, and governance—from the Polkadot Relay Chain to the Asset Hub system parachain. This architectural change is part of Polkadot's roadmap toward the JAM (Join-Accumulate Machine) protocol, aiming to reduce Relay Chain state bloat, enable faster upgrades, and improve overall scalability.

For developers, this means that after the migration, all user-facing operations (checking balances, staking, voting) must be directed to the Asset Hub's RPC endpoints rather than the Relay Chain. The Relay Chain will continue to handle consensus, parachain auctions, and cross-chain messaging (XCM), but it will no longer serve these user-level pallets.

Why Is the Migration Happening?

The Relay Chain originally hosted all core functionality, but as Polkadot grew, this monolithic design became a bottleneck:

• State bloat: The Relay Chain's state grew large, making upgrades slower and more complex.
• Upgrade friction: Changes to staking or governance required runtime upgrades affecting the entire network.
• Scalability limits: The Relay Chain could not easily scale user-facing features independently.

By moving these pallets to Asset Hub, Polkadot achieves:

• Modularity: Each system chain can evolve independently.
• Lower fees: Asset Hub offers significantly lower transaction fees and existential deposits (0.01 DOT vs 1 DOT).
• Better user experience: Fee payment in any supported asset, direct access to Ethereum bridges, and expanded asset support.

Timeline and Phases

The migration follows a testnet-first approach:

1. Kusama: Migration executed on October 7, 2025.
2. Polkadot: Migration executed on November 4, 2025.
3. Westend (testnet): Earlier testing phases throughout 2025.

No user action is required for fund safety—assets move automatically. However, developers must update their infrastructure to point to the correct RPC endpoints.

Impact on RPC Endpoints

After migration, the following changes apply to RPC queries:

Example: Querying a Balance After Migration

curl -H "Content-Type: application/json" -d '{
  "jsonrpc":"2.0",
  "id":1,
  "method":"chain_getBalance",
  "params":["YOUR_ACCOUNT_ADDRESS"]
}' https://rpc.asset-hub.polkadot.io

Replace YOUR_ACCOUNT_ADDRESS with the actual Polkadot address. Ensure your RPC provider supports the Asset Hub chain.

Updating Your Infrastructure

For dApps and Wallets

1. Update RPC URLs: Change your network configuration to point to Asset Hub RPC endpoints. For example, if using OnFinality, select the "Polkadot Asset Hub" network from the supported networks list.
2. Test with Kusama: Since Kusama migrated first, use it as a staging environment to validate your changes.
3. Handle legacy queries: Some users may still query the Relay Chain; implement fallback logic or redirects.

For Staking Services

Staking operations (nominate, validate, reward claims) now occur on Asset Hub. Update your staking UI or backend to use the Asset Hub's staking pallet. The RPC methods remain the same, but the endpoint changes.

For Indexers and Explorers

Reconfigure your indexer to subscribe to Asset Hub blocks and events for balances, staking, and governance. The Relay Chain will no longer emit these events.

Common Pitfalls and Troubleshooting

• Using old Relay Chain endpoints: Queries will return empty or error responses. Double-check your network configuration.
• Hardcoded endpoint URLs: Replace any hardcoded Relay Chain URLs with Asset Hub URLs in your codebase.
• Ignoring testnet results: Test thoroughly on Kusama or Westend before the Polkadot migration window closes.
• Assuming no action needed: While end users don't need to move funds, developers must update their infrastructure.

Choosing an RPC Provider for Asset Hub

A reliable RPC provider is critical post-migration. When evaluating providers, consider:

• Network support: Does the provider offer dedicated endpoints for Polkadot Asset Hub and Kusama Asset Hub?
• Rate limits: Ensure the provider's free or paid tier matches your application's traffic.
• WebSocket support: For real-time subscriptions (e.g., staking events), WebSocket endpoints are essential.
• Archive data: If you need historical state, check for archive node support.

OnFinality provides RPC endpoints for both Polkadot Asset Hub and Kusama Asset Hub, with flexible pricing and dedicated node options for production workloads.

Key Takeaways

• The Asset Hub migration moves balances, staking, and governance from the Relay Chain to the Asset Hub system parachain.
• No user action is required for fund safety, but developers must update RPC endpoints and infrastructure.
• Kusama migrated on October 7, 2025; Polkadot on November 4, 2025.
• Test your integrations on Kusama or Westend before relying on Polkadot mainnet.
• Choose an RPC provider that supports Asset Hub endpoints with adequate performance and reliability.

Frequently Asked Questions

Q: Do I need to move my DOT tokens? A: No. The migration happens automatically; your tokens remain in your account, now on Asset Hub.

Q: Will my staking rewards be affected? A: No. Staking rewards continue as before, but queries and operations must use Asset Hub endpoints.

Q: What happens to the Relay Chain? A: The Relay Chain continues to handle consensus, parachain auctions, and XCM. It no longer manages balances, staking, or governance.

Q: How do I find the Asset Hub RPC endpoint? A: Use the network's official endpoint or a provider like OnFinality. For Polkadot Asset Hub: https://rpc.asset-hub.polkadot.io. For Kusama Asset Hub: https://rpc.asset-hub.kusama.io.

Q: Is there any downtime during migration? A: The migration is designed to be seamless with minimal downtime. Some services may experience brief delays during the transition.

Q: Where can I get support? A: Join the Asset Hub Migration Support Telegram channel or refer to the Polkadot Support Center.