@avalabs/crypto-sdk

Cross-platform crypto SDK facade. Exposes a single unified API for batched address derivation; the bundler picks the right backend per platform via package.json exports conditions — no Platform.OS checks in consumer code.

• React Native → routes to @avalabs/crypto-nitro (native C++ via Nitro Modules)
• Web / extension / Node → routes to @avalabs/crypto-wasm (Emscripten WASM)

Install

You must install the wrapper for your target platform alongside this package. The wrappers are declared as optional peer dependencies, so npm/pnpm won't warn if you forget — but import from this package will fail at runtime when the missing wrapper can't be resolved.

# React Native (iOS + Android)
pnpm add @avalabs/crypto-sdk @avalabs/crypto-nitro

# Browser / Chrome extension / Node
pnpm add @avalabs/crypto-sdk @avalabs/crypto-wasm

Cross-platform libraries that consume this SDK should re-declare the wrappers as optional peer deps so the choice propagates to the final app.

Usage

import {
  init,
  deriveAddressesFromXpubs,
  deriveAddressesForEvm,
  deriveAddressesForBtc,
  deriveAddressesForSvm,
  deriveAddressesForAvalanche,
} from '@avalabs/crypto-sdk';

// Required once before any derive*() call on the wasm backend.
// A no-op on the nitro backend, but always safe to call.
await init();

// Xpub-driven flow (Ledger / watch-only).
const rows = await deriveAddressesFromXpubs(
  evmXpub,
  avalancheXpubs,
  /*isTestnet=*/ false,
  /*accountIndices=*/ [0, 1, 2, 3, 4],
);

// Per-chain encoders — feed already-derived pubkeys.
const evmAddresses = await deriveAddressesForEvm(evmPubkeys);
const btcAddresses = await deriveAddressesForBtc(evmPubkeys, /*isTestnet=*/ false);
const svmAddresses = await deriveAddressesForSvm(ed25519Pubkeys);
const avaxBundles = await deriveAddressesForAvalanche(avaxPubkeys, evmPubkeys, false);

See src/contract.ts for the full CryptoApi interface.

API surface

| Function | Input shape | Returns | | ------------------------------------------------------------------------------ | ------------------------------------ | -------------------------------------- | | init() | — | Promise<void> | | deriveAddressesFromXpubs(evmXpub, avalancheXpubs, isTestnet, accountIndices) | strings + index array | Promise<DerivedSecp256k1Addresses[]> | | deriveAddressesForEvm(publicKeys) | 33-byte compressed secp256k1 pubkeys | Promise<string[]> (EIP-55 hex) | | deriveAddressesForBtc(publicKeys, isTestnet) | 33-byte compressed secp256k1 pubkeys | Promise<string[]> (bech32 P2WPKH) | | deriveAddressesForSvm(publicKeys) | 32-byte Ed25519 pubkeys | Promise<string[]> (base58) | | deriveAddressesForAvalanche(avaxPks, evmPks, isTestnet) | parallel pubkey arrays | Promise<DerivedAvalancheAddresses[]> |

All batched calls cap at 1024 elements per invocation and validate per-element pubkey length / SEC1 prefix at the boundary.

What's not in the facade

Lower-level primitives — sign, verify, signSchnorr, verifySchnorr, getPublicKey*, getExtendedPublicKey, pointAddScalar — currently exist only in @avalabs/crypto-nitro. To use them on React Native, import them directly from the nitro package:

import { sign, verify, getExtendedPublicKey } from '@avalabs/crypto-nitro';

Adding the equivalents to @avalabs/crypto-wasm is what would let those operations move into this facade.