moos is an open-source atomic-swap client. I run a maker for it: you take one of my offers from your own machine, lock your side on-chain, and the swap either completes both legs or returns yours after a timelock. No account, no deposit with me, no identity check.
| Custody | None. Your keys stay on your machine. |
|---|---|
| Fee | 1% of the trade, split between both sides. |
| Minimum | About €5. |
| Software | Rust, GPL-3.0, source on Radicle. |
| Network | Tor-native offer book; Ethereum mainnet escrow. |
How a swap works
Two chains cannot be swapped by trusting a middleman, so moos does not use one. The Monero leg goes to a per-swap address that only the swap secret can spend; the Ethereum leg goes to a public escrow contract. One secret settles both sides, and if it is never revealed the timelocks let each side take its funds back.
- Get the client. Build it from source (below). The first run creates your identity on your machine — an Ethereum key and a Monero wallet. Nothing about it is sent to me.
- Pick an offer. The client lists offers with direction, rate, fee and limits. An offer is signed and self-contained: the exact amount you pay and receive is shown before you commit.
- Fund your side. XMR goes to the per-swap address; ETH goes to the escrow contract with enough left for gas. I fund my side of the same swap.
- Claim or refund. If I claim, the secret is revealed on-chain and your side unlocks. If I stall past the deadline, you refund yourself. Neither of us can move the other's funds in between.
The escrow is public and immutable:
0x377ed3a60007048DF00135637521170628De89E5 on Ethereum mainnet
(Etherscan).
Before it runs a swap the client checks that the bytecode at that address matches the build it was
compiled with. The contract has no owner function: funds move only through a swap's own claim or
refund.
Fees
| Protocol fee | 1% of the trade, charged in XMR inside the lock transaction. |
|---|---|
| Split | Half each side. The client shows your exact payout and fee before you confirm. |
| Minimum trade | About €5. The client also refuses any payout too small to pay for its own Monero sweep. |
| Gas and network fees | Paid to the chains, not to me. A reverted Ethereum transaction still costs gas. |
| Accounts, deposits, withdrawals | None — there is nothing to deposit and nothing to withdraw. |
What can go wrong
- It is alpha software. Version 0.1.0. Use amounts you can afford to lose.
- It takes time. Chain confirmations set the pace; a swap takes minutes, and the refund path can take up to the on-chain deadline.
- Dust stays put. XMR payouts that cannot cover their own sweep are refused up front, but tiny leftovers below the Monero fee can remain in the claim wallet.
- Your keys are yours alone. The identity lives in
rundir-mainnet/identity. Back it up. I cannot recover it for you. - I am one person with one machine. If I go offline mid-swap, the protocol still lets you refund after the deadline; it does not need my cooperation.
- The chains are public. Tor hides the network path, not the coins.
Run it
Linux x86-64. You need Rust (rustup) and a C toolchain. The first run downloads the pinned Monero CLI once; the build itself is offline from vendored crates.
# install Radicle first: https://radicle.xyz
rad clone rad:z2SEZa9usoc7o2pMNNUGn2zjSjdrV moos
cd moos
./moos./moos builds the client and its maker daemon, then opens the terminal UI. Mainnet is
the default; --devnet starts a local test chain instead.
The source is on Radicle at rad:z2SEZa9usoc7o2pMNNUGn2zjSjdrV. Its delegate key is
z6MkovoPb1igAceXq73EatP2KACC3MG727Rq2kecwScdYtx5; commits signed by that key are the
code this page describes.
Why this exists
I run this because I wanted to swap these two coins without an exchange account. It is a small service on purpose: one maker, one machine, and a client you can read. The status page is generated from the daemon's own journals every ten minutes, so you can see what has actually been recorded rather than what a website claims.
Contact
SimpleX is the only direct channel: https://smp9.simplex.im/c#VItzf7jh401dMzrnaz3BuqOhCh1VCe-8d5bAkjLj_u0. I answer when I am at the machine. For protocol questions the source is better documentation than I am.