P2P Bitcoin Exchanges (KYC-free)

Direct peer-to-peer Bitcoin trading without a centralized order book or KYC custody.

Bisq 1

• Java desktop app.
• Operates entirely over Tor.
• Decentralized order book via P2P network.
• Multisig escrow (2-of-2 with arbitrator).
• Fiat methods: SEPA, Zelle, Revolut, cash by mail, etc.
• Hard network cap of 0.250 BTC per trade (TradeLimits.MAX_TRADE_AMOUNT, introduced in v1.10.0 and unchanged through v1.10.7, 25 August 2026); default local limit 0.1 BTC.
• BSQ token for fee/governance; still the home of BSQ markets and the DAO.

Maturity: very mature (2014+).

1 May 2026 exploit

The taker supplies the trade's miner-fee value to the maker, and it was not validated against negative numbers — an attacker used this to make the maker compute an incorrect multisig output value. 11.59104 BTC lost across 10 users, altcoin trades only; fiat trades were shielded by account-age witness signing. Refund Angels advanced 10.98538295 BTC to reimburse victims; repayment out of BTC trade fees is proposed, not ratified — phased in over DAO cycles at 25% / 50% / 75% of the Burning Men share, with a 12-18 month settlement horizon called realistic (Bisq blog, 16 June 2026).

Hardening shipped in v1.10.0: validation added across deposit, payout, delayed-payout and mediated-payout transactions, trade amounts and prices, fees, multisig keys and raw inputs; price deviation capped at 25%; a hard network cap on trade amount introduced at 0.125 BTC (before v1.10.0 the ceiling came from the DAO MAX_TRADE_LIMIT parameter alone, default 2 BTC); XMR auto-confirmation disabled by network filter pending an audit. The cap was raised to 0.250 BTC in v1.10.1. Bisq 2 was not affected.

Bisq 2 / Bisq Easy

• Separate codebase (bisq-network/bisq2), latest v2.1.12 (22 August 2026). Bisq 1 is not deprecated.
• Bisq Easy (first Bisq 2 trade protocol, launched March 2024) has no multisig escrow — security is proportional to seller reputation. The buyer pays fiat first, so only sellers need a score.
• Trade range 6-600 USD equivalent; reputation buys headroom at 200 score per USD, and 1200 is the minimum score to post a sell offer (BisqEasyTradeAmountLimits, v2.1.12).
• Sellers settle on-chain or over Lightning — seller pays the mining fee or the LN routing fee, buyer pays neither (Bisq Easy wiki, Mining fees).
• Disputes go to a mediator, not an arbitrator — there is no escrow to split.
• Mobile: bisq-network/bisq-mobile ships Bisq Easy Node on Google Play (anode_0.13.0, 5 September 2026) and Bisq Connect, a thin client for a Bisq 2 node you trust, on Google Play and iOS TestFlight (connect_0.9.0, 11 September 2026).
• Unaffected by the Bisq 1 May 2026 exploit (different codebase).
• Bisq MuSig is the planned escrowed successor protocol and the project's stated highest strategic priority for 2026 (Bisq blog, June 2026); not shipped as of v2.1.12.

Maturity: Bisq Easy in production since 2024; MuSig in development.

RoboSats

• Tor-only (also accessible via clearnet).
• Federated — there is no single coordinator. Since v0.6.0-alpha "The Federation Layer" (17 March 2024) anyone can run a coordinator; the client app joins every registered coordinator's order book and shows per-coordinator reputation, fees and policies.
• The client rate-limits young coordinators: 250,000 sats max order, +30% every 2016 blocks, "mature" (any order size) after roughly 12,288 blocks (~6 months). Pre-v0.6.0 "Founder" coordinators are mature by default.
• Book ordering is a lottery weighted by DevFund donation value; since v0.8.7-alpha (9 September 2026) the weight is the coordinator's live devfund% x fee rate, falling back to static federation.json.
• Lightning HODL-invoice escrow; optional on-chain payout ("swap").
• "Robot identity" — stateless, no account, just a per-trade key.
• Multi-language (12+).
• Fiat methods: SEPA, Wise, Revolut, cash, gift cards, others.
• Trades typically smaller (50-5000 EUR equivalent).
• Frontend simple HTML; sat-denominated.

Maturity: 2022+, growing; still alpha-tagged (v0.8.7-alpha, 9 September 2026).

Hodl Hodl

• Web-based.
• 2-of-3 multisig escrow.
• KYC-optional (most trades are KYC-free).
• Diverse fiat methods.
• Loans (HodlOptions) plugin.
• Trades range $50 to many thousands.

Maturity: 2017+, mature.

Compared

Use cases

• First sats acquisition without exchange registration.
• Privacy-preserving off-ramp / on-ramp.
• Trades in censored jurisdictions.
• Avoiding KYC attestation chains in cluster-analysis.

Trade execution

Generic flow:

1. Buyer sends fiat to seller off-chain (bank, cash, gift card).
2. Seller releases BTC from multisig (or LN HTLC) once fiat received.
3. Disputes: arbitrator (Bisq 1), mediator (Bisq Easy) or the hosting coordinator (RoboSats).

Limitations

• Slower than exchange-based trading (per-trade time hours, not seconds).
• Lower volume — large trades hard to fill.
• Counterparty risk — KYC-free means no recourse if counterparty vanishes after fiat sent.

See also

• coinjoin/SKILL.md
• ../../lightning/submarine-swaps/SKILL.md
• tor/SKILL.md