Self-custody that rewrites the rules.

ERC-4337 is the account-abstraction standard that makes your wallet a programmable smart contract instead of a single private key. That enables counterfactual addresses, gas sponsorship (pay no gas, or pay it in any token), and batched atomic transactions. Vaultr implements the v0.7 UserOperation flow with a bundler and paymaster.

Your master key is split with Shamir’s Secret Sharing over GF(256) into three shares — device, server, and recovery — any two of which reconstruct it. Compromising any single location yields one useless share, and you can recover with your device and recovery shares without Vaultr’s cooperation.

Nine networks: Ethereum, Base, Polygon, Arbitrum, Optimism, BNB Chain, Bitcoin, Solana, and Vaultr’s own Blockmaze L0. That spans EVM, Bitcoin’s UTXO model, and Solana’s SVM — all from one wallet.

Every significant transaction requires a separate verification layer from your login: a 64-byte one-time challenge, verified by OTP or device biometric, issuing a one-time-use token consumed atomically to prevent replay. Compromising your session does not let an attacker move funds.

Yes. Base rates are fixed and published, all fee math uses BigInt arithmetic (no floating-point rounding), and holding or staking BMZ reduces fees by up to 90%.