OnchainKit Migration Skill

Migrate apps from @coinbase/onchainkit to standalone wagmi/viem components with zero OnchainKit dependency.

Before Starting

Create a mistakes.md file in the project root:

# Migration Mistakes & Learnings

Track errors, fixes, and lessons learned during OnchainKit migration.

## Errors

## Lessons Learned

Append every error, fix, and lesson to this file throughout the migration. This file improves the skill over time.

Migration Workflow

Migrations MUST happen in this order. Do not skip steps.

Step 1: Detection

Scan the project to understand current OnchainKit usage:

1. Search all files for @coinbase/onchainkit imports
2. Identify which components are used:
   • Provider: OnchainKitProvider (always present if using OnchainKit)
   • Wallet: Wallet, ConnectWallet, WalletDropdown, WalletModal, Connected
   • Transaction: Transaction, TransactionButton, TransactionStatus
   • Other: Identity, Avatar, Name, Address, Swap, Checkout, etc.
3. Check package.json for existing wagmi, viem, @tanstack/react-query dependencies
4. Identify the project's styling approach (Tailwind, CSS Modules, styled-components, etc.)
5. Report findings to the user before proceeding

Step 2: Provider Migration (always first)

Read references/provider-migration.md for detailed instructions and code.

Summary:

1. Ensure wagmi, viem, and @tanstack/react-query are installed
2. Create wagmi-config.ts with chain and connector configuration
3. Replace OnchainKitProvider with WagmiProvider + QueryClientProvider
4. Remove @coinbase/onchainkit/styles.css import
5. Remove any SafeArea or MiniKit imports from layout files

Validation gate: Run npm run build (or the project's build command). Must pass before continuing. If it fails, fix errors and document them in mistakes.md.

Step 3: Wallet Migration (after provider)

Read references/wallet-migration.md for detailed instructions and code.

Summary:

1. Create a WalletConnect component using wagmi hooks (useAccount, useConnect, useDisconnect)
2. Component includes a modal with wallet options: Base Account, Coinbase Wallet, MetaMask
3. Shows truncated address + disconnect button when connected
4. Replace all OnchainKit wallet imports and component usage

Validation gate: Run npm run build. Must pass before continuing. Document any errors in mistakes.md.

Step 4: Transaction Migration (after wallet)

Read references/transaction-migration.md for detailed instructions and code.

Summary:

1. Check the chainId prop on existing <Transaction /> components -- add any missing chains to wagmi-config.ts
2. Create a TransactionForm component using wagmi hooks (useWriteContract, useWaitForTransactionReceipt, useSwitchChain)
3. Component handles the full lifecycle: idle, pending wallet confirmation, confirming on-chain, success, error
4. Replace all OnchainKit transaction imports (Transaction, TransactionButton, TransactionStatus, TransactionSponsor, etc.)
5. Update the calls array format -- use address, abi, functionName, args with proper as const typing
6. Map onStatus callback to the new lifecycle status names (init, pending, confirmed, success, error)

Validation gate: Run npm run build. Must pass before continuing. Document any errors in mistakes.md.

Step 5: Cleanup

1. Search for any remaining @coinbase/onchainkit imports -- there should be none
2. Optionally remove @coinbase/onchainkit from package.json dependencies
3. Run final npm run build to verify everything works
4. Update mistakes.md with final lessons learned

Troubleshooting

Build fails after provider migration

• Missing dependencies: Ensure wagmi, viem, @tanstack/react-query are installed
• Type errors with wagmi config: Check that chains array has at least one chain and transports has a matching entry
• "use client" missing: Both the provider and wallet components must have "use client" directive

MetaMask SDK react-native warning

• The warning Can't resolve '@react-native-async-storage/async-storage' is harmless in web builds. It comes from MetaMask SDK and does not affect functionality.

Wallet won't connect

• Verify the wagmi config has the correct connectors configured
• Check that WagmiProvider wraps the component tree before any wallet hooks are used
• Ensure QueryClientProvider is inside WagmiProvider

Transaction receipt stuck in pending

• Symptom: Transaction hash appears, tx confirms on-chain, but UI stays stuck on "Transaction in progress..." forever
• Cause: useWaitForTransactionReceipt has no RPC to poll because the transaction's chain is missing from the wagmi config's chains + transports
• Fix: (1) Add the target chain to wagmi-config.ts chains array AND transports object. (2) Always pass chainId to useWaitForTransactionReceipt({ hash, chainId }) so it polls the correct chain

Transaction targets wrong chain

• The TransactionForm auto-switches chains, but the target chain must exist in the wagmi config's chains array and transports object
• Common: add baseSepolia for testnet transactions (chainId 84532)

Next.js page export restrictions

• Next.js only allows specific named exports from page files. Exporting contract call arrays or ABI constants from a page file will cause a build error
• Fix: make them non-exported const declarations or move them to a separate module

ABI type errors after transaction migration

• When defining ABIs inline, use as const on the array for proper type inference
• Mark individual fields like type: 'function' as const and stateMutability: 'nonpayable' as const

Existing wagmi setup detected

• If the project already wraps with WagmiProvider, do NOT add another one
• Instead, just update the existing wagmi config to include the needed connectors
• OnchainKit's provider detects and defers to existing wagmi providers -- the standalone setup should too

Important Notes

• Always use wagmi and viem directly. Never import from @coinbase/onchainkit.
• The baseAccount connector comes from wagmi/connectors, not from a separate package.
• wagmi-config.ts must include every chain the app transacts on. If the original OnchainKit <Transaction chainId={X} /> used a specific chain, that chain must be in both chains and transports. Without it, useWaitForTransactionReceipt will hang forever.
• If the project uses Tailwind, use Tailwind classes for the components. If not, adapt to inline styles or the project's existing styling approach (e.g., CSS Modules).
• Do not export contract call arrays, ABI constants, or other non-page values from Next.js page files. Use non-exported constants or a separate module.
• Inspect the OnchainKit source code in node_modules/@coinbase/onchainkit/src/ if you need to understand how a specific component works internally.