Other Chain·Bitcoin · EVM
BOB (Build on Bitcoin)
Hybrid Layer-2 powered by Bitcoin and Ethereum. Combines Bitcoin security and BTC liquidity with EVM execution, plus a Gateway SDK for native BTC-in/BTC-out app flows.
- 01EVM apps that accept native BTC
- 02BTC-collateralized DeFi
- 03ordinals/runes-aware dApps
- 04hybrid BTC + ETH UX
- 05BTC staking
- pnpm add @gobob/bob-sdk viem wagmi
| Variable | Scope | Description |
|---|---|---|
| NEXT_PUBLIC_BOB_RPC_URL | Client | BOB JSON-RPC endpoint (mainnet chain id 60808). |
| BOB_GATEWAY_API_KEY | Server | API key for the BOB Gateway SDK if using hosted endpoints. |
Use BOB to build EVM apps that accept native BTC. Add chain id 60808 to wagmi/viem with `NEXT_PUBLIC_BOB_RPC_URL`. To accept BTC, use `@gobob/bob-sdk` `GatewaySDK('mainnet')` then `getQuote({ toToken, toUserAddress, amount })` and `startOrder(quote)` to get a BTC deposit PSBT — sign with the user's BTC wallet (Xverse/Leather/Unisat) and broadcast. The Gateway relayer auto-mints WBTC/tBTC/solvBTC on the EVM side. For ordinals/runes, use the SDK's `EsploraClient` and `Inscription`/`Rune` helpers to read inscriptions in Solidity-adjacent flows.
- ⚑Gateway orders depend on Bitcoin confirmation count — pick the right `toToken`/strategy combo and surface BTC mempool latency in the UI; don't promise instant settlement.
- ⚑BOB is a hybrid L2: phase 1 is an OP Stack rollup on Ethereum, phase 2 adds BTC finality — security assumptions evolve, document the current trust model.
- ⚑Bridged BTC variants (WBTC, tBTC, solvBTC) have different issuer trust assumptions; treat them as distinct assets, not fungible '1 BTC'.
- ⚑PSBTs returned from Gateway must be signed by the same wallet that owns the inputs — user wallet selection (Xverse vs Leather vs Unisat) materially affects fee estimation and signing UX.
- ⚑Withdrawals back to L1 BTC are not synchronous — fall back to the relayer's status webhook rather than polling EVM events.