smom-dbis-138/docs/operations/integrations/METAMASK_BRIDGE_SWAP.md

MetaMask Bridge & Swap Support for ChainID 138

Current status and workarounds for Bridge and Swap features on ChainID 138.

Current Status

ChainID 138 is not currently supported in MetaMask's native Swaps and Bridge features. Users must use third-party bridges and DEXs until native support is added.

Swaps (In-Wallet Aggregator)

Known error: "No XChain Swaps native asset found for chainId: eip155:138"

If you see this error in MetaMask while connected to Chain 138, it can appear when clicking Send or Swap (depending on MetaMask version; the Send flow sometimes uses the same LavaPack/XChain code):

Error: No XChain Swaps native asset found for chainId: eip155:138
  at LavaPack.loadBundle.s.getNativeAssetForChainId (...)

Cause: MetaMask’s LavaPack/XChain logic only supports a fixed list of chains. Chain 138 is not in that list. In some versions, the Send UI triggers this path (e.g. for gas or asset lookup), so the error appears on Send as well as Swap. This is not about using eth_sendTransaction vs eth_sendRawTransaction (the error happens in the UI before any RPC), and it is not caused by the Chain 138 Snap or its allowlisting—the extension uses its own LavaPack list and does not ask Snaps for native asset.

If it happens on Send:

• Recommended — Chain 138 Send page: Use the Chain 138 Snap companion site Send page (e.g. /send on the deployed Snap site). This page uses eth_sendTransaction from the dApp context, bypassing MetaMask's broken Send UI—connect MetaMask, open the Send page, ensure Chain 138, enter recipient and amount, then click Send.
• Alternative — Different entry point: Try sending from the account/balance view (e.g. click the balance or “Send” from the asset list) instead of the home “Send” button, in case your MetaMask version uses a different code path.
• Alternative — Another wallet: Use a wallet that supports custom EVM networks (e.g. add Chain 138 via Chainlist) and does not rely on this backend for Send.

If it happens on Swap: Do not use the in-wallet Swaps button for Chain 138. Use a DEX that supports Chain 138 (see Workaround: Use DEX UI below).

Receiving and using dApps on Chain 138 work normally; the failure is in MetaMask’s own Send/Swap UI for unsupported chains.

Current Limitation

MetaMask Swaps supports a fixed set of networks:

• Ethereum
• BNB Chain
• Polygon
• Avalanche
• Optimism
• Arbitrum
• zkSync Era
• Linea
• Base
• Sei

ChainID 138 is not on this list, so the in-wallet Swaps button will not aggregate quotes natively.

Workaround: Use DEX UI

Users can swap tokens via DEX UIs that support ChainID 138:

1. Connect to ChainID 138: Add network to MetaMask
2. Navigate to DEX: Open DEX that supports ChainID 138
3. Connect Wallet: Connect MetaMask wallet
4. Execute Swap: Execute swap through DEX UI

Recommended DEXs

List DEXs that support ChainID 138 (to be populated after DEX deployment):

• DEX 1: [URL] - Description
• DEX 2: [URL] - Description

Bridge (Portfolio Bridge)

Current Limitation

MetaMask Portfolio Bridge supports a curated network set:

• Ethereum
• BNB Chain
• Linea
• Polygon
• Arbitrum
• Optimism
• Avalanche
• Base
• zkSync Era

ChainID 138 is not currently supported.

Workaround: Use Third-Party Bridges

Users must bridge via third-party bridges until native support is added.

Recommended Bridges

List bridges that support ChainID 138 (to be populated after bridge deployment):

• Bridge 1: [URL] - Description
• Bridge 2: [URL] - Description

Bridge Integration Requirements

For bridges to work with ChainID 138:

1. Network Support: Bridge must support ChainID 138
2. Liquidity: Sufficient liquidity on both sides
3. Security: Audited bridge contracts
4. Monitoring: Bridge monitoring and alerts

Buy/Sell (Fiat On/Off-Ramp)

Priority flows (mainnet liquidity + ramps)

Recommended user flows (operator must fund mainnet liquidity first):

• On-ramp: Buy on Ethereum Mainnet via ramp → bridge to Chain 138. See MAINNET_RAMP_USER_FLOWS.md.
• Off-ramp: Bridge Chain 138 → Mainnet → sell on mainnet via ramp. See MAINNET_LIQUIDITY_AND_RAMPS_PRIORITY.md and MAINNET_RAMP_USER_FLOWS.md.

Current Limitation

MetaMask's on-/off-ramp partners only support certain chains/tokens. ChainID 138 assets are not currently supported natively.

Workaround: Bridge from Supported Chains

1. Buy on Supported Chain: Buy ETH/tokens on a supported chain (Ethereum, etc.)
2. Bridge to ChainID 138: Use third-party bridge to bridge to ChainID 138
3. Use on ChainID 138: Use bridged assets on ChainID 138

Alternative: CEX Withdrawal

1. Buy on CEX: Buy ETH/tokens on centralized exchange
2. Withdraw to ChainID 138: Withdraw directly to ChainID 138 address (if supported)
3. Use on ChainID 138: Use withdrawn assets on ChainID 138

Recommended On-Ramp Partners

List on-ramp partners that support ChainID 138 (to be populated):

• Partner 1: [URL] - Description
• Partner 2: [URL] - Description

How to Fund ChainID 138

Method 1: Bridge from Ethereum

1. Bridge Provider: Use a bridge that supports Ethereum → ChainID 138
2. Connect Wallets: Connect MetaMask wallets for both chains
3. Initiate Bridge: Initiate bridge transaction
4. Wait for Confirmation: Wait for bridge confirmation
5. Receive on ChainID 138: Receive bridged assets on ChainID 138

Method 2: CEX Withdrawal

1. Buy on CEX: Buy ETH on centralized exchange
2. Withdraw: Withdraw to ChainID 138 address (if supported)
3. Wait for Confirmation: Wait for withdrawal confirmation
4. Receive on ChainID 138: Receive assets on ChainID 138

Method 3: Peer-to-Peer

1. Find Seller: Find someone willing to sell ETH on ChainID 138
2. Arrange Transfer: Arrange transfer via trusted method
3. Receive Assets: Receive assets on ChainID 138

Path to Native Support

Swaps Integration

To enable native Swaps support:

1. Business Development: Engage with Consensys for partnership
2. Liquidity Requirements: Ensure sufficient liquidity for aggregator
3. DEX Integration: Integrate with DEXs on ChainID 138
4. Testing: Test swap functionality
5. Regulatory Compliance: Ensure regulatory compliance

Bridge Integration

To enable native Bridge support:

1. Business Development: Engage with Consensys for partnership
2. Bridge Providers: Partner with bridge providers
3. Security Audit: Complete security audit
4. Testing: Test bridge functionality
5. Monitoring: Set up bridge monitoring

On-Ramp Integration

To enable native on-ramp support:

1. Partner Integration: Partner with on-ramp providers
2. Regulatory Compliance: Ensure regulatory compliance
3. Testing: Test on-ramp functionality
4. User Experience: Optimize user experience

Business Development

Consensys Outreach

1. Initial Contact: Reach out to Consensys business development
2. Proposal: Submit integration proposal
3. Requirements: Discuss requirements and timeline
4. Partnership: Establish partnership agreement
5. Implementation: Implement integration

Tracking

• Monitor MetaMask feature updates
• Track network support announcements
• Engage with Consensys regularly
• Submit feature requests

Documentation

User Guides

• How to Bridge to ChainID 138: Step-by-step bridge guide
• How to Swap on ChainID 138: Step-by-step swap guide
• How to Fund ChainID 138: Funding options guide

Developer Guides

• Bridge Integration: How to integrate bridges
• DEX Integration: How to integrate DEXs
• On-Ramp Integration: How to integrate on-ramps

References

• MetaMask Swaps
• MetaMask Portfolio Bridge
• Consensys Business Development