Tools · Bridges & conversion

Boltz

Non-custodial atomic swaps across on-chain Bitcoin, Lightning, Liquid and Ark — the submarine-swap bridge. ⚠ Swap services suspended indefinitely since 2026-08-03.

What it is

Boltz is a non-custodial bridge that performs atomic (submarine) swaps across on-chain Bitcoin, Lightning, Liquid and Ark, exposed via a RESTful API. Because the swaps are atomic, neither side can take the funds and run — it’s the trust-minimized way to move value across those rails without a custodian. For agent treasuries, Boltz is a building block for rebalancing and converting between layers at the boundary.

A bridge tool — it crosses between rails. This card is the infrastructure view of Boltz; its venue role — cross-asset swaps, which it offered until 2026-08-03 — has a separate exchange card, retained unfeatured for the record. See Exchange for where conversion mechanics fit relative to the pure substrate.

When to use it

• Moving value between on-chain BTC, Lightning, Liquid and Ark without a custodian. (Not available on the hosted service while swaps are suspended.)
• Acquiring inbound Lightning liquidity or sweeping to on-chain via atomic swaps.
• Programmatic conversion at the edge of an agent treasury.

Dependencies

Non-custodial wallets on the rails you’re swapping between (on-chain Bitcoin, Lightning, and/or Liquid) and a client-side integration of the API; swaps pay network fees plus a provider-set swap fee and need correct refund/timeout handling. No account, no KYC.

Quick start

Do not integrate against the hosted service — swaps are suspended (see above). When it is running, Boltz’s own agent-facing docs are explicit that you must use an official SDK and must not implement the REST API directly: “Hand-rolling the swap protocol is error-prone and can cause loss of user funds… The REST API reference is for SDK/library authors only.” Start from the SDK list at api.docs.boltz.exchange/libraries.md. The service is powered by boltz-backend (github.com/BoltzExchange/boltz-backend), which you can self-host — that path is unaffected by the suspension and is the one to reach for today.

Gotchas

• Non-custodial only if integrated correctly — Boltz explicitly warns integrators to keep API clients client-side and never run swaps or store refund data on users’ behalf, or the non-custodial guarantee breaks.
• Submarine swaps require correct refund/timeout handling; abandoned or failed swaps need user-controlled refund flows.
• Swap liquidity and limits are provider-set.