Babylon

Bitcoin staking protocol — let BTC holders stake BTC to secure external Proof-of-Stake systems (Cosmos chains, L2s, DA layers) without bridging or wrapping.

Backed by Babylon Labs. Babylon Genesis mainnet live since April 2025. Trustless Bitcoin Vaults were announced on BitVM3 in August 2025; as of September 2026 they are on public testnet only and the shipped protocol verifies redemption with BABE, not BitVM3.

Architecture

Native BTC staking: BTC stays on Bitcoin chain in special staking output.
Slashable security: misbehavior on PoS chain → slash via pre-signed slashing tx.
No custody: no third party holds the BTC.
Self-custodial: stakers control their keys.

Mechanism

1. BTC holder locks BTC in a Bitcoin staking output (specialized script).
2. Holder signs (off-chain) attestations for blocks on a PoS chain.
3. PoS chain rewards BTC stakers (in PoS chain's native token).
4. If staker double-signs / equivocates → pre-signed slashing tx
   spendable, BTC slashed from staking output.

Key: BTC never leaves Bitcoin. Slashing path enforced via Bitcoin script (CSV + spending conditions).

Trustless Bitcoin Vaults (TBV)

History. The 6 August 2025 announcement pitched BitVM3-based vaults that would let BTC flow into BTC-secured PoS systems without a custodian. Both the mechanism and the scope changed before anything shipped — do not quote the 2025 framing as current.

Status, 16 September 2026. Public testnet only: Bitcoin signet plus Ethereum testnet, with mock Sepolia borrow assets and no monetary value. docs.babylonlabs.io fronts the whole site with "Public testnet live". The 7 October 2025 vault-first roadmap post targeted vault mainnet for "early next year"; that has not landed.

Mechanism. Redemption is verified with BABE, not BitVM3. BABE ("Verifying Proofs on Bitcoin Made 1000x Cheaper", Garg, Kolonelos, Sergeevitch, Sridhar, Tse — January 2026) keeps BitVM3's on-chain cost while cutting off-chain storage and setup by three orders of magnitude; BitVM3 needs ~42 GiB per garbled circuit. It pairs a witness-encryption scheme for linear pairing relations with a garbled circuit for EC scalar multiplication, making Groth16 verification practical in existing Bitcoin script. No fork required.

Scope. TBV is native BTC collateral for Ethereum DeFi, not liquidity for BTC-secured PoS systems. The application registry lists the Aave v4 borrowing adapter and nothing else.

Structure:

BTC sits in a Taproot BTCVault output whose every spend path is pre-signed at vault creation; afterwards no party can invent a spend.
Roles: depositor, one Vault Provider per vault, App Keepers, Universal Challengers, and a transitional Security Council. None of them custodies the depositor's BTC.
Peg-out posts an SP1 proof of the Ethereum redemption event, verified on Bitcoin via BABE, then waits a ~3-day challenge window (432 BTC blocks) before payout.
Depositor fallbacks: self-claim using a Winternitz one-time signature (WOTS) committed at peg-in, and a relative-CSV refund on the Pre-PegIn output if activation never completes.
Testnet caps: 0.01–0.4 BTC per vault, 0.4 BTC per position and per address, 10 BTC total across the Aave v4 application.

Docs: https://docs.babylonlabs.io/trustless-bitcoin-vault/

Bridge to Cosmos

January 2025 collaboration with Fiamma:

BitVM2-based trustless Bitcoin bridge to Cosmos chains.
Babylon-secured: Cosmos chain pays BTC stakers; if Cosmos validators fail, BTC stakers slash Cosmos validators (not the BTC).

Use cases

BTC staking yield without giving up custody.
Securing new PoS chains with Bitcoin's economic value.
Cross-chain Bitcoin DeFi without wrapping.

Status & roadmap

Babylon Genesis (Phase-2) mainnet launched 10 April 2025 at 10:00 UTC. Phase-1 BTC staking locks ran through 2024 and its caps closed in December 2024 with ~57 000 BTC locked.
Trustless Vaults announcement 6 Aug 2025; public testnet as of September 2026 (see above).
Q2 2026 was the stated roadmap window for deeper integrations with multiple PoS chains — historical roadmap, and as of 16 September 2026 no delivery is visible. The 7 October 2025 vault-first roadmap post explicitly pushed Bitcoin-supercharged networks (BSNs) and EVM on Babylon Genesis behind the vaults, the babylonlabs-io/babylon CHANGELOG from v4.2.2 through v4.4.0 is dependency bumps, security advisories and an intentionally empty v4.4 upgrade, and cosmos-bsn-contracts / rollup-bsn-contracts have published nothing since v1.0.0-rc.3 (9 Sep 2025) and v1.0.0-rc.1 (13 Aug 2025) respectively.
Latest babylonlabs-io/babylon release is v4.4.0, published 6 August 2026. Check the tag list rather than quoting a version from memory: https://github.com/babylonlabs-io/babylon/releases
DefiLlama's babylon-protocol series puts TVL at $3.21B for 15 September 2026 (and $3.11B for 16 September). Treat any single figure as a dated snapshot and re-read the series: https://api.llama.fi/protocol/babylon-protocol

Downstream: BTC liquid staking tokens

Most BTC that reaches Babylon does so through a liquid-staking wrapper rather than direct staking, so the wrapper's trust model — not Babylon's — is what a holder is actually exposed to. Two matter, and one of them has already moved off Babylon staking:

Lombard (LBTC) — launched as Babylon-staked BTC, and is still widely described that way. It is no longer accurate: during 2026 LBTC's yield source transitioned off Babylon staking to a covered-call options strategy managed by Bitwise. Lombard's own "Yield Model History" table dates the earlier cut-over: before 22 July 2025 holders claimed BABY manually, and from that date all yield auto-compounded into the LBTC/BTC exchange rate (https://docs.lombard.finance/use/lbtc/understanding-yield, fetched 16 September 2026). See lombard/SKILL.md.
Solv (SolvBTC / xSolvBTC) — multi-chain tokenized BTC behind a Safe multisig with a Guardian contract. See solv/SKILL.md.

The general lesson: "BTC liquid staking" branding outlives the staking. Re-check where a given LST's yield comes from before attributing it to Babylon.

Compared to BTC wrapping

Aspect	Babylon staking	wBTC / tBTC / etc.
Custody	Self	Custodian / threshold
Bridge tx	Bitcoin only	Cross-chain bridge tx
Slashing	Via Bitcoin script	Via centralized authority
Fee	Bitcoin tx fee for stake / unstake	Bridge fee + chain fee
Yield source	PoS chain's emission	Bridge service fees / DeFi yield

Limitations

PoS chain dependency — yield depends on which chain you secure.
Vaults are testnet-only — as of September 2026 TBV runs on signet + Ethereum testnet, on BABE rather than BitVM3, with a transitional Security Council and small exposure caps.
Slashing complexity — staker must understand penalty conditions.

bitcoin-l2-babylon