Fees

All fees come from underlying protocols — Tuck takes no part of any fee. Fees are paid to the Tuck Shield pool (for privacy operations), to Robinhood Chain (for gas), and to Uniswap pools (for swaps).

Every figure below is denominated in ETH, the native gas token of Robinhood Chain.

What You Actually Pay For

Gas on Robinhood Chain has two components, as on any Arbitrum-stack rollup:

L2 execution gas — the cost of running your transaction on the chain. Very cheap, and stable.
L1 data cost — your transaction's share of posting batch data to Ethereum blobs. This is set by Ethereum blob demand, not by Robinhood Chain, and it's the part that moves.

Tuck quotes both together as a single ETH number. When an estimate drifts, blob pricing is almost always the reason.

Two costs that exist on account-model chains do not exist here: there is no rent or minimum balance to keep an account open, and no per-token account to create before you can receive an ERC-20. Receiving a new token costs the recipient nothing.

Fee Reference

Standard fees used across all operations:

Tuck Shield withdrawal: 0.0002 ETH base + 0.35% of amount
Tuck Shield shielding: 0.0001 ETH reserved from the amount
ETH transfer gas: ~0.000004 ETH per transaction
ERC-20 transfer gas: ~0.000006 ETH per transfer
ERC-20 approval: ~0.000002 ETH, one-time per token per shard
Uniswap swap gas: ~0.00002 ETH per swap
Safety buffer: 0.00003 ETH added to estimates

Note: withdrawal fees apply when reimbursing the Tuck relayer for gas. The relayer submits your ERC-2771 meta-transaction and pays gas upfront, then is automatically reimbursed from your shielded balance through a Tuck Shield withdrawal (0.0002 ETH + 0.35%).

How Fees Work

Tuck uses a relayer system to handle gas automatically. When you perform operations (sends, swaps, consolidations), your shard wallet signs a meta-transaction and the Tuck relayer submits it, paying the ETH gas upfront. After each transaction completes, the relayer is automatically reimbursed from your shielded ETH balance through a Tuck Shield withdrawal.

This is why shard wallets never need an ETH balance of their own — which matters for privacy, since funding every shard with gas would create exactly the on-chain links the shard architecture exists to break.

You need sufficient shielded ETH to cover both the operation itself and the relayer reimbursement. All of this happens automatically in the background — just ensure you have enough shielded ETH for your operations.

Send Fees

Private ETH Sends

Tuck Shield withdrawal fee only. The recipient receives exactly the amount you specify — Tuck calculates the withdrawal needed (send amount + fees). No separate gas charge.

Public ETH Sends

Gas (~0.000004 ETH per shard if spread across multiple shards) paid by the relayer, then reimbursed from your shielded balance (withdrawal fee: 0.0002 ETH + 0.35% of the reimbursement amount).

ERC-20 Token Sends

Gas (~0.000006 ETH per transfer) paid by the relayer and reimbursed from your shielded balance. Identical for public and private shards, except that a private shard is converted to public after the send. Stock Tokens cost the same as any other ERC-20 to transfer.

Swap Fees

Public ETH / ERC-20 to Token Swaps

Consolidation gas (~0.000006 ETH per source shard, if tokens are spread across several) + approval (~0.000002 ETH, if not already set) + Uniswap swap gas (~0.00002 ETH). The relayer pays all gas upfront and is reimbursed from your shielded balance.

Public ERC-20 to ETH Swaps

Same as above, plus 0.0001 ETH shielding reserve deducted from output. Minimum output after reserve: 0.0005 ETH. Shielding takes 10-30 seconds for ZK proof generation.

Private ETH to Token Swaps

Tuck Shield withdrawal fee (covers swap amount + fees) + approval (~0.000002 ETH, if needed) + Uniswap swap gas (~0.00002 ETH). The shard wallet pays gas from the withdrawn amount. Minimum swap: 0.00025 ETH.

Private ERC-20 to Token Swaps

Uniswap swap gas (~0.00002 ETH) + approval (~0.000002 ETH, if needed). The relayer pays gas upfront and is reimbursed from your shielded balance. No consolidation needed.

Private ERC-20 to ETH Swaps

Same as private ERC-20 → token swaps, plus 0.0001 ETH shielding reserve deducted from output. Minimum output after reserve: 0.0005 ETH.

Pool Fees

Every Uniswap swap also pays the pool's own fee tier, taken out of the output amount rather than charged in ETH. It's shown in the quote before you confirm. On thinly traded Stock Token pairs, this plus slippage will typically dwarf the gas cost.

Other Flow Fees

Receive Fees

Free. If ETH needs shielding, a 0.0001 ETH reserve is deducted from the received amount. Amounts < 0.0001 ETH are converted to shard wallets instead of shielded. Receiving ERC-20 tokens, including Stock Tokens, costs nothing at all — no transaction is required.

Cleanup Flow Fees

Consolidation: ~0.000006 ETH per token transfer. Shield All ETH: 0.0001 ETH per shield operation (0 if none, 0.0001 for one type, 0.0002 for both). Temp wallet cleanup: negligible — balance checks and local deletion only. Plus the relayer reimbursement withdrawal. See Cleanup Flows documentation for details.

Bridge Fees

Tuck Shield withdrawal fee (for the private send to the bridge temp wallet) + Robinhood Chain gas (~0.000004 ETH) + route-specific costs. The canonical Arbitrum bridge additionally requires an Ethereum L1 claim transaction after the ~7-day challenge window, paid in L1 gas — typically far more than everything you spend on Robinhood Chain combined. Omnichain and NEAR Intents routes charge protocol and liquidity fees included in the quote. See Bridging documentation for details.

How Fees Are Displayed

Tuck shows a fee breakdown before every confirmation: Network Gas (L2 execution + L1 data), Approvals (if applicable), Relayer Reimbursement, Shielding Reserve (for swaps to ETH), and Total Estimated Fees. Estimates include a 0.00003 ETH safety buffer and may vary ±10-20% as Ethereum blob prices move. Tuck reads live gas parameters from the chain when possible for accurate estimates.