Overview

@cavos/kit gives your users a self-custodial smart account that they control with a silent device key — no seed phrase, no MPC, no browser extension, no popups. A login (OAuth or email) only derives the wallet address; the actual signing happens invisibly with a non-extractable secp256r1 (P-256) key that lives on the device.

The model is chain-agnostic — the same API works across high-performance chains. Starknet, Solana, and Stellar are available today. See Chains.

TypeScript

import { Cavos } from "@cavos/kit";

const cavos = await Cavos.connect({
  chain: "starknet",                   // "starknet" | "solana" | "stellar"
  network: "testnet",
  identity: { userId: user.id, email: user.email },
  appSalt: "my-app",
  appId: process.env.NEXT_PUBLIC_CAVOS_APP_ID,
  paymasterApiKey: process.env.CAVOS_PAYMASTER_API_KEY!,
});

if (cavos.status === "ready") {
  await cavos.execute(calls); // gasless; signed silently by the device key
}

Mental model

Piece	Role
Identity	A stable `userId` (from your login) + an `appSalt`. Together they derive the wallet address — device-independent.
Device signer	A non-extractable secp256r1 key on the device (WebCrypto in the browser). Signs `sha256(tx_hash)` with no UI.
Account contract	The on-chain Cavos account for the target chain (a Cairo `DeviceAccount` on Starknet today). Validates device signatures on-chain and is the sole authority over its signers.
Chain adapter	The per-chain layer (address derivation, signature encoding, deploy calls). `StarknetAdapter`, `SolanaAdapter`, and `StellarAdapter` today. See Chains.
Paymaster	Sponsors deploy + execute so transactions are gasless for the user.

What makes it different

No seed phrases. The user never sees or manages a private key.
MPC-free. No key sharding, no signing servers. The key is whole and on the device.
Verifiable. Signatures are checked on-chain by the account contract, not by a backend.
Deterministic address. Same identity → same wallet address, every time, before deployment.
Gasless. Deploy and execution are sponsored through the Cavos paymaster.
Multi-device + passkey 2FA + passphrase recovery. Three non-custodial ways to never lose access.