# Bitcoin Wallet Standard (/connectors/bitcoin-wallet-standard)



`@usebutr/bitcoin` discovers Bitcoin wallets two ways:

* **Wallet Standard** — Phantom, Magic Eden, Leather, OKX (modern), …
* **Injected fallback** — `window.unisat` (Unisat, OKX legacy, generic
  `window.btc`) and `sats-connect` (Xverse).

The fallback is opt-in via `discoverInjectedBitcoinAdapter` and runs when no
Wallet Standard wallet announces.

## Discovery [#discovery]

`autoDiscovery()` from `@usebutr/wallets` handles Bitcoin discovery (both
routes) automatically. For a Bitcoin-only setup, compose the two sources:

```ts
import { createWalletSource } from "@usebutr/core";
import {
  discoverBitcoinAdapters,
  discoverInjectedBitcoinAdapter,
} from "@usebutr/bitcoin";
import { WalletManagerProvider } from "@usebutr/react";

const discovery = createWalletSource((onAdapter) => {
  const offStandard = discoverBitcoinAdapters(onAdapter);
  const offInjected = discoverInjectedBitcoinAdapter(onAdapter, {});
  return () => {
    offStandard();
    offInjected();
  };
});

<WalletManagerProvider discovery={discovery}>
  {children}
</WalletManagerProvider>
```

<Callout type="info">
  `@usebutr/bitcoin` lazily imports `@wallet-standard/app` (an optional peer dependency). Restored
  Bitcoin wallets can land in `pendingIds` for a moment during that warmup — see
  [hydration](/concepts/hydration).
</Callout>

## Capabilities [#capabilities]

Resolved from the wallet's advertised features via `resolveBitcoinCapabilities`:

* `signMessage` — true only if `bitcoin:signMessage` is advertised. Note this
  is a Bitcoin Signed Message (BIP-322-ish), not interchangeable with EVM
  signatures.
* `signTransaction` — true via `bitcoin:signPsbt`. PSBT in, signed PSBT out;
  the consumer finalises and broadcasts.
* `sendTransaction` — true via `bitcoin:sendTransfer` (one-shot send) or
  `bitcoin:signPsbt` with `broadcast: true` (depending on what the wallet
  advertises).
* `subscribe` — true via the Standard `change` event.
* `switchChain` — limited: switching mainnet ↔ testnet typically means
  re-connecting in the wallet UI.

Always branch on [capabilities](/concepts/capabilities).

## Working with the signer [#working-with-the-signer]

`getSigner()` on a Bitcoin adapter returns the `WalletStandardWallet`. You
call features directly (or bridge into `bitcoinjs-lib`):

```ts
const walletStd = (await wallet.connector.getSigner()) as WalletStandardWallet;
const feature = walletStd.features["bitcoin:signPsbt"];
const account = walletStd.accounts[0];
const [{ psbt: signedPsbt }] = await feature.signPsbt({
  account,
  psbt: unsignedPsbt, // base64
});
```

See the [demo-with-bitcoin](https://github.com/pedroapfilho/usebutr/tree/main/apps/demo-with-bitcoin)
app for the full build-and-broadcast flow with `bitcoinjs-lib`.

## Chains [#chains]

`BITCOIN_CHAINS_LIST` / `BITCOIN_CHAINS` ship mainnet, testnet, and regtest
(keyed by CAIP-2 — `bip122:<genesis block hash>`). `slugify`,
`resolveBitcoinCapabilities`, and `GENERIC_BITCOIN_ICON` are exported for
adapter authors.

<Callout type="warn">
  **Address formats vary by wallet.** Phantom advertises native SegWit (bech32) only; Xverse and
  Unisat expose multiple address formats (payment vs ordinal). Read `account.walletAddress` and
  detect the format from its prefix.
</Callout>

<Callout type="info">
  **Source:** `packages/bitcoin/src` (`wallet-standard.ts`, `injected/`, `capabilities.ts`). Used by
  `apps/demo-with-bitcoin` and (via `@usebutr/wallets`) `apps/demo-vite`.
</Callout>