# Zero-fee commitments for mobile wallets

**URL:** <https://delvingbitcoin.org/t/zero-fee-commitments-for-mobile-wallets/1453>\
**Category:** Protocol Design\
**Tags:** lightning\
**Created:** [February 18, 2025, 1:06pm UTC](https://delvingbitcoin.org/t/zero-fee-commitments-for-mobile-wallets/1453 "2025-02-18T13:06:24Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![harding](https://delvingbitcoin.org/user_avatar/delvingbitcoin.org/harding/32/925_2.png) [@harding](https://delvingbitcoin.org/u/harding)\
**Post date:** [February 18, 2025, 2:31pm UTC](https://delvingbitcoin.org/t/zero-fee-commitments-for-mobile-wallets/1453/2 "2025-02-18T14:31:14Z")

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> [@t-bast](#):
>
> A very simple proposal to fix that is to have the peer always sign two versions of HTLC transactions:
> 
> - the default one that doesn’t pay any fee and needs additional on-chain inputs
> - and another one in a custom TLV of `commitment_signed` at a high feerate that matches the currently observed feerate

This seems pretty clever. Am I understanding correctly that the fees for the high feerate will be deducted from the balance of the channel opener in the current way? Since we would always expect the mobile wallet to be the channel opener, that means (1) it costs the peer nothing to offer the mobile wallet a high feerate option and (2) the mobile wallet has an incentive to not use the high-feerate option unless it’s actually necessary for safety or recovering liquidity from a stale channel.

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