Eclair Dual-Fund Errors - Fix Interactive Channel Opening Issues

What Is Eclair Dual-Funding?

Dual-funded channels (BOLT2 interactive tx construction) allow both peers to contribute funds when opening a channel, enabling instant inbound liquidity.

Common Errors

• dual_fund not supported by peer
• InteractiveTxSessionFailed: invalid tx_add_input
• DualFundingAborted: remote sent tx_abort
• rbf attempt rejected: feerate too low

Enable Dual-Funding in Eclair

# eclair.conf
eclair.features.option_dual_fund = optional

# Restart Eclair after config change
sudo systemctl restart eclair

Open a Dual-Funded Channel

# Open with both sides contributing
curl -u :password -X POST http://localhost:8080/open \
  -d nodeId=<peer_node_id> \
  -d fundingSatoshis=500000 \
  -d pushMsat=0 \
  -d channelType=anchor_outputs_zero_fee_htlc_tx

RBF Fee Bump a Pending Open

# If channel open is stuck, bump via RBF
curl -u :password -X POST http://localhost:8080/rbfopen \
  -d channelId=<channel_id> \
  -d targetFeerateSatByte=20

Troubleshooting

• Peer must support option_dual_fund — check their node features
• Both nodes need sufficient on-chain UTXOs
• Use tx_abort carefully — it cancels the whole session
• RBF requires new feerate > original by at least 1 sat/vbyte

Dual-funding setup failing? DM on Nostr.