Types of Crypto Wallets: Custodial vs Non-Custodial, Hot vs Cold
The wallet type you choose determines who controls the private key, your regulatory obligations, and the entire technical architecture. Getting this decision right at the start saves months of rework.
| Type | Key Custody | UX | Compliance Burden | Examples |
|---|---|---|---|---|
| Hot (Non-Custodial) | User | Seed phrase backup | Low — user bears risk | MetaMask, Rainbow |
| Cold (Hardware) | User (offline device) | Device sign flow | Low | Ledger, Trezor |
| Custodial (Exchange) | Platform | Email login | High — MSB/VASP license | Coinbase, Binance |
| MPC (Threshold Sig) | Shared (parties) | Biometric / PIN | Medium | Fireblocks, ZenGo |
| Smart Contract (AA) | User (contract) | Social recovery / gasless | Low–Medium | Safe, Argent, Kernel |
Non-Custodial (Hot Wallet)
You generate and never store the private key. The user holds their seed phrase. Cannot comply with wire recall requests — but gives users full ownership. Best for consumer wallets. Examples: MetaMask, Trust Wallet, Phantom.
Custodial (Exchange Wallet)
Your platform holds and manages private keys on behalf of users. Requires full compliance stack: KYC/AML, HSM key management, travel rule, and MSB/VASP licensing. 2–4× higher development cost than non-custodial.
Cold (Hardware) Wallet
Private keys stored on a dedicated physical chip that never connects to the internet. Signing happens on the device — transactions are transmitted via USB or Bluetooth. Highest security for long-term holdings. SDK integration: Ledger Connect Kit, Trezor Connect.
MPC Wallet
Private key never exists in full — it is split across 2-of-3 or 3-of-5 parties using threshold ECDSA or EdDSA. No seed phrase to lose. Best for institutional/enterprise wallets. Providers: Fireblocks, ZenGo, Silence Laboratories.
Hot wallets (connected to the internet) offer convenience but expose keys to online attack vectors. Cold wallets (air-gapped) are virtually immune to remote attack but add friction. Most production wallets use a hybrid: hot wallet for daily spending, cold wallet for savings. Your app can support both by implementing hardware wallet signing via Ledger Connect Kit or Trezor Connect SDK.
Key Features of a Modern Crypto Wallet
Users in 2026 expect far more than send and receive. A competitive crypto wallet must integrate the entire DeFi and Web3 ecosystem. Here are the features that define market-ready wallets.
Multi-Chain Support
Support Ethereum, Bitcoin, Solana, BNB Chain, Polygon, Avalanche, and Cosmos from a single BIP39 seed. Use chain-specific BIP44 derivation paths. Display unified portfolio across all chains.
Seed Phrase (BIP39)
12 or 24-word mnemonic generated from cryptographically secure entropy. Displayed once during onboarding, never transmitted. Users must verify by re-entering random words. The foundational recovery mechanism.
QR Code Send/Receive
Generate QR codes for receiving with optional amount and memo. Scan sender QR with camera for address input. Supports EIP-681 payment URIs (ethereum:0x...?value=...) and BIP21 for Bitcoin.
DEX / Swap Integration
Embedded token swap via 0x Protocol, 1inch, or Jupiter (Solana). Quote aggregation across multiple DEXes, price impact warnings, slippage controls, and MEV protection (Flashbots Protect or private mempools).
NFT Support
Gallery view for ERC-721 and ERC-1155 tokens with metadata and images from Alchemy NFT API. Send NFTs with transfer dialogs. Floor price display per collection. Spam NFT filtering. Solana Metaplex NFT support.
DeFi Integration
Staking (Lido, Rocket Pool), lending/borrowing (Aave, Compound), and yield farming positions. DeFi position tracking via Zapper or Zerion API. Always display APY, risk score, and smart contract audit status.
WalletConnect v2
Connect to any dApp by scanning a QR code. Supports multi-chain sessions, typed data signing (EIP-712), and deep link return flow. The standard for dApp-wallet communication since v1 deprecation.
Biometric Authentication
Face ID, Touch ID, or Android fingerprint unlock gates access to the encrypted keychain item. PIN/pattern as fallback. Auto-lock after 5 minutes of inactivity. Screen recording/screenshot prevention during seed phrase display.
Push Notifications
Real-time alerts for incoming transfers, confirmed transactions, price movements, and DeFi liquidation risk. Alchemy Notify webhooks or Tenderly alerts power notification delivery via FCM and APNs.
Portfolio Analytics
Historical P&L, asset allocation pie chart, 24h/7d/30d performance. Fiat value in 150+ currencies. Transaction history with in/out classification and USD value at time of transaction.
Address Book & ENS
Save frequently used addresses with custom labels. Resolve ENS names (vitalik.eth), Solana naming service (.sol), and Unstoppable Domains (.crypto) to addresses. Warn on first-time sends to new addresses.
Gas Estimation & EIP-1559
Show Low / Market / Fast gas tiers with estimated confirmation time and USD cost. EIP-1559 base fee + priority fee breakdown. Custom gas for power users. Gasless option via ERC-4337 paymaster integration.
HD Wallet Architecture (BIP32 / BIP39 / BIP44)
Hierarchical Deterministic wallets generate an infinite tree of key pairs from a single master seed. This is the standard for all modern non-custodial wallets and is foundational to any multi-chain implementation.
Mnemonic Seed Phrases
12 or 24 random words encode 128–256 bits of entropy. Words chosen from a standardized 2048-word wordlist. An optional BIP39 passphrase adds a "25th word" for additional protection. The seed is the backup — never transmit or store server-side. Users must write it on paper.
Hierarchical Derivation
Master seed → Master Private Key → Child Keys via HMAC-SHA512. Hardened derivation (m/44'/...) isolates coin branches so a compromised child key cannot leak parent keys. Extended public keys (xpub) allow watch-only wallets and address generation without private key exposure.
Multi-Coin Path Standard
Derivation path: m / purpose' / coin_type' / account' / change / index. Bitcoin = coin_type 0, Ethereum = 60, Solana = 501, Cosmos = 118. One seed deterministically manages hundreds of chains — this is how Trust Wallet and Coinbase Wallet support 60+ chains from a single backup.
The seed phrase must be shown only once and never stored on your servers. Implement a 3-step verification flow: (1) display words, (2) ask user to confirm they wrote them down, (3) verify by asking them to enter 3–4 random words from their list. Add screenshot prevention and require airplane mode or offline confirmation during this step.
Key Management, Secure Enclave & HSM
How you store and protect private keys determines whether you build a wallet or a honey pot. The right storage approach depends on your wallet type and who your users are.
Secure Enclave (Mobile)
iOS Secure Element (SEP) and Android StrongBox Keymaster store encrypted key material in hardware-backed secure storage isolated from the main processor. The private key is encrypted at-rest and unlocked only by biometric or PIN. The key never leaves the device — even Codazz cannot access it. Use react-native-keychain to interface with these APIs.
MPC (Threshold Signatures)
Multi-party computation splits the private key across 2-of-3 or 3-of-5 parties using threshold ECDSA (secp256k1) or EdDSA. No single server holds the full key. Signing requires collaboration across parties without reconstructing the key. Providers: Fireblocks (enterprise), ZenGo (consumer), Silence Laboratories (open-source SDK), Privy (embedded).
AWS CloudHSM / Azure Dedicated HSM
FIPS 140-2 Level 3 hardware security module — private keys generated inside tamper-proof hardware and never exported in plaintext. $1.45/hr per CloudHSM cluster. Required for exchange-grade custodial wallets handling institutional client funds. Pairs with CloudTrail for complete audit logging of every signing operation.
Shamir Secret Sharing
Splits the encrypted seed into N shares where any K shares reconstruct it (3-of-5 is standard). Individual shares are stored separately: encrypted cloud backup, local device, and a trusted third party. Used for recovery flows when a user loses their device. Never transmit all shares together.
| Storage Method | Security Level | UX Friction | Best For | Monthly Cost |
|---|---|---|---|---|
| Secure Enclave | Very High | Biometric tap | Consumer mobile | $0 (device) |
| MPC (3-of-5) | Very High | Biometric / PIN | Enterprise / fintech | $500–$5K |
| AWS CloudHSM | Highest (FIPS L3) | Invisible | Custodial exchange | $1,045/mo/cluster |
| Encrypted DB | Medium | Password | Dev/testing only | $0 |
| Shamir Backup | High (recovery) | Complex setup | Key recovery flows | $0 (open source) |
Building a Non-Custodial Mobile Wallet
React Native + ethers.js is the dominant stack for non-custodial mobile wallets in 2026. Flutter is viable but lags 12–18 months behind in blockchain library maturity. Here is the core architecture and implementation flow.
Seed Generation & Storage
Generate 128-bit entropy via crypto.getRandomValues() → BIP39 mnemonic → display to user once. Encrypt with user PIN/biometric via react-native-keychain (iOS Keychain / Android Keystore). Never transmit. Use AES-256-GCM encryption for at-rest storage.
Address Derivation
Use ethers.js v6 HDNodeWallet.fromPhrase() for EVM chains. Use @solana/web3.js with BIP44 path m/44'/501'/0'/0' for Solana. Derive multiple account indices (0, 1, 2...) lazily. Cache derived public keys — never cache private keys.
Transaction Signing
Fetch nonce from RPC node (eth_getTransactionCount). Build transaction object with EIP-1559 fee params. Sign locally — private key never leaves Secure Enclave. Broadcast signed tx via eth_sendRawTransaction. Monitor receipt with exponential backoff polling.
Balance & History
Use Alchemy / Infura / QuickNode for EVM RPC calls. Alchemy Token API for ERC-20 balances. Alchemy NFT API for NFT holdings. The Graph Protocol for complex historical queries. Cache balances in SQLite via WatermelonDB. Invalidate on new block.
Biometric Auth Layer
react-native-biometrics wraps TouchID / FaceID / Android Fingerprint. Biometric gate unlocks an encrypted Keychain item containing the encrypted seed key. PIN/pattern as fallback. Session token valid for 5 minutes — re-auth required for every signing operation above a threshold amount.
Push Notifications
Monitor addresses via Alchemy Notify webhooks or Tenderly alert policies. Send push via FCM (Android) and APNs (iOS) through your Node.js backend. Deliver alerts for incoming transfers, pending confirmation, confirmed tx, price thresholds, and DeFi position liquidation warnings.
React Native has a richer blockchain ecosystem — ethers.js v6, WalletConnect Web3Wallet SDK, and hardware security libraries are production-grade. Flutter wallet tooling (flutter_web3, web3dart) is catching up but lags in WalletConnect v2 and ERC-4337 support. For maximum ecosystem compatibility in 2026, choose React Native. Flutter is acceptable if your team is Flutter-first and you limit chain support to EVM + Solana only.
Multi-Chain Support Architecture
Supporting Ethereum, Bitcoin, and Solana from a single seed requires chain-specific derivation and different transaction models. Bitcoin uses UTXO; Ethereum and Solana use account-based models. Each chain has its own signing algorithm, fee model, and RPC protocol.
| Chain | BIP44 Coin | TX Model | Signing Algorithm | Recommended Library |
|---|---|---|---|---|
| Ethereum + EVM L2s | 60' | Account-based (EIP-1559) | ECDSA secp256k1 | ethers.js v6 / viem |
| Bitcoin | 0' | UTXO (SegWit/Taproot) | ECDSA secp256k1 | bitcoinjs-lib |
| Solana | 501' | Account-based | EdDSA Ed25519 | @solana/web3.js |
| Tron | 195' | Account-based | ECDSA secp256k1 | TronWeb |
| Cosmos/IBC | 118' | Account-based | ECDSA secp256k1 | CosmJS |
| Polkadot | 354' | Account-based | Sr25519 / Ed25519 | @polkadot/api |
Use a unified balance indexer — Alchemy Portfolio API or self-hosted Covalent — to aggregate ERC-20, SPL, and native balances into a single API response. For Bitcoin UTXO balance, use Electrum server or Blockstream Esplora REST API. Cache aggressively: balance calls are the #1 RPC cost driver in production wallets. Use Redis for hot cache (60 second TTL) and PostgreSQL for historical balance snapshots used in portfolio analytics.
WalletConnect v2 Integration
WalletConnect is the standard protocol for connecting wallets to dApps across any chain. v1 was fully deprecated in November 2023 — v2 is mandatory for all new wallet builds. Failing to support WalletConnect v2 means users cannot connect to Uniswap, OpenSea, or any major dApp.
Pairing Protocol
Wallet scans QR code containing a WalletConnect URI (wc:... format). Establishes an encrypted relay session via WalletConnect Cloud (relay.walletconnect.com). Symmetric encryption key derived from ECDH over secp256k1. Session stored locally with topic + symmetric key.
Session Management
Sessions are persistent and survive app restarts. Session proposal includes required namespaces (chains, methods, events). Wallet approves namespaces it supports or rejects the connection entirely. Sessions expire after 7 days and must be renewed by the dApp. Show active sessions list with one-tap disconnect per dApp.
dApp Integration (Web3Modal v3)
On the dApp side: @walletconnect/web3wallet SDK with wagmi v2 or ethers.js adapters. Web3Modal v3 (WalletConnect's own modal) or RainbowKit handle wallet selection UI. Supports multi-chain switching (wallet_switchEthereumChain), personal_sign, eth_sendTransaction, and EIP-712 typed data signing.
Deep Link Flow (Mobile)
dApp opens universal link → wallet app opens via deep link (wc:// scheme) → user signs inside wallet → wallet returns to dApp via configured redirect URI. Register universal links in App Transport Security (iOS) and App Links (Android). Use Linking.openURL() in React Native.
DeFi & NFT Integration
A modern crypto wallet is not just a balance viewer — it is a full DeFi front-end. Wallets that only send and receive lose users to MetaMask, Coinbase Wallet, and Rabby within weeks. Here are the integrations users expect in 2026.
Token Swaps
Integrate 0x Protocol or 1inch for EVM chains (quote aggregation across Uniswap, Curve, Balancer). Jupiter for Solana. Fetch quotes with price impact, minimum received, and route visualization. MEV protection via Flashbots Protect. Never custody user funds during swap — always use atomic contract execution.
NFT Gallery
Alchemy NFT API v3 returns metadata, images, floor prices, rarity, and collection info in a single call. Group by collection. Support ERC-721, ERC-1155, and Solana Metaplex. Filter spam NFTs using Alchemy's isSpam flag. Allow users to hide individual NFTs. Enable direct listing to OpenSea via seaport SDK.
Token Price Feeds
CoinGecko API (free: 30 req/min) for token prices in USD and 50+ fiat currencies. Cache prices for 60 seconds to avoid rate limits. For real-time DeFi-grade prices: Pyth Network on-chain oracle or CoinGecko Pro. Show 24h price change with green/red indicator.
Gas Estimation
eth_estimateGas for gas limit. eth_maxFeePerGas from node for EIP-1559 fee data. Show Low / Market / Fast tiers with estimated confirmation time and USD cost. For gasless UX, integrate an ERC-4337 paymaster (Biconomy Paymaster, Pimlico, or StackUp).
Staking & Yield
Lido SDK for liquid stETH staking. Rocket Pool for decentralized rETH. Aave V3 SDK for lending / borrowing positions. Show APY prominently from DeFi Llama yields API. Always display risk disclosures: smart contract risk, slashing risk, liquidity risk.
Portfolio Analytics
Portfolio USD value, daily PnL, and asset allocation. Transaction history with fiat value at time of tx. Zerion API or Zapper API provide pre-calculated DeFi positions (LP, staking, lending). For full control, build on top of Alchemy Transfers API and your own event indexer.
Security Considerations & Hardening
Crypto wallets are the highest-value attack targets in mobile software. A single vulnerability can drain every user who approved a token. These are the non-negotiable security requirements you must implement before launch.
Encryption at Rest
- AES-256-GCM encryption for all key material
- Biometric or PIN-derived key for encryption
- Never store seed phrase or private key in plaintext
- Use iOS Keychain with kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly
- Android Keystore with setUserAuthenticationRequired(true)
Biometric & PIN Auth
- Face ID / Touch ID via react-native-biometrics
- Fallback PIN with bcrypt/argon2 hashing
- Auto-lock after 5 min inactivity or app background
- Re-authenticate before every signing operation
- Limit PIN retry attempts — lock after 10 fails
Phishing Protection
- Show full domain in dApp connection screen
- Warn on unknown dApps not in trusted registry
- Require explicit confirmation for PERMIT / APPROVE
- Show human-readable tx simulation (Blowfish, Pocket Universe)
- Flag unlimited token approvals with prominent warning
Clipboard Hijacking
- Detect clipboard address replacement on paste
- Show first + last 6 chars of address prominently
- Highlight any address change after paste
- Require manual re-confirmation if address changed
- Add verified address book with ENS resolution
Address Poisoning
- Never auto-populate from transaction history
- Display full address — never truncated only
- Filter zero-value spam tokens from history display
- Flag addresses visually similar to known saved addresses
- Add one-tap address verification via QR scan
App & Runtime Security
- Root / jailbreak detection (react-native-jail-monkey)
- Screenshot prevention on seed phrase screens
- SSL certificate pinning for all backend API calls
- Disable USB debugging detection on Android
- No analytics SDK with access to keypresses or clipboard
No crypto wallet should go to production without a third-party security audit. Budget $15K–$50K for a mobile security audit (Trail of Bits, Halborn, Cure53) covering key storage, signing flows, and network communications. For custodial wallets, also audit your backend infrastructure and HSM integration. Publish the audit report publicly — it is a trust signal that attracts users.
Crypto Wallet Development Process: 6 Phases
Building a production crypto wallet is not a single sprint — it is a disciplined engineering process spanning discovery through post-launch hardening. Here is how Codazz structures every wallet engagement.
Recommended Tech Stack (2026)
The battle-tested stack for production multi-chain wallets in 2026. Every library listed is actively maintained and used in production wallets with $1B+ in assets.
ethers.js v6 is the established choice with wider documentation and community examples. viem is newer, fully TypeScript-typed, more modular, and performs better in bundle-size-sensitive contexts (web wallets). For mobile React Native, ethers.js v6 is more mature. For web-based wallet UI, viem + wagmi is the preferred 2026 stack.
web3.js v4 (ChainSafe rewrite) is actively maintained again after years of stagnation. However, ethers.js v6 has a larger community, better TypeScript types, and more third-party integrations in the wallet space. New wallets should default to ethers.js v6 or viem. web3.js makes sense only if integrating with legacy Truffle tooling.
Compliance: FinCEN, MiCA & Travel Rule
Non-custodial wallets have minimal regulatory burden globally. Custodial wallets and exchange wallets face significant licensing requirements that vary by jurisdiction. Getting this wrong can result in FinCEN enforcement actions, fines, and forced shutdown.
| Jurisdiction | Custodial License | Non-Custodial | KYC Required | Regulator |
|---|---|---|---|---|
| USA | FinCEN MSB Registration + state MTLs | No license required | Yes (>$3,000 wire) | FinCEN / state regulators |
| EU (MiCA) | CASP Registration (2024+) | No license required | FATF Travel Rule >€1,000 | National NCAs (ESMA oversight) |
| Canada | FINTRAC MSB Registration | No license required | Yes (>$10,000 CAD) | FINTRAC |
| UAE (ADGM/DIFC) | FSRA / DFSA Virtual Asset License | No license required | Yes | FSRA / DFSA |
| Singapore | MAS PSA (Major/Standard) | No license required | Yes (CDD required) | MAS |
| UK | FCA Cryptoasset Registration | No license required | Yes | FCA |
FinCEN MSB Registration
US custodial wallets must register as Money Services Businesses with FinCEN before launching. Registration is free but requires a BSA compliance program, AML officer appointment, employee training, and ongoing SAR/CTR reporting. 49 states also require separate Money Transmitter Licenses (MTLs) — budget $50K–$200K and 12–18 months for full US rollout.
EU MiCA (Markets in Crypto-Assets)
MiCA took full effect in December 2024. Custodial wallet providers operating in the EU must register as Crypto-Asset Service Providers (CASPs) with their national competent authority (NCA). MiCA harmonizes requirements across all 27 EU member states — one license covers the entire EU. Key obligations: whitepaper disclosure, capital requirements (€50K–€150K), and segregated client assets.
FATF Travel Rule
Transfers above $1,000 (US) or €1,000 (EU MiCA) between VASPs require originator and beneficiary information to travel with the transaction. Technical implementation via Notabene, Sygna Bridge, or Travel Rule Protocol (TRP). Critical for any custodial wallet allowing withdrawals to external addresses. FATF member countries are progressively enforcing this — non-compliance blocks correspondent banking relationships.
KYC/AML Integration
For custodial wallets: integrate Sumsub, Jumio, or Onfido for document verification + selfie liveness check. Target onboarding completion rate: 70%+ (Sumsub reports industry average of 68%). Chainalysis KYT or Elliptic for blockchain transaction monitoring. Set risk thresholds for automated blocking vs manual review.
OFAC Sanctions Screening
Screen all wallet addresses against OFAC's SDN list before allowing any transaction. Use Chainalysis Sanctions API or TRM Labs for real-time address screening. Block transactions to/from flagged addresses. Log all screening decisions for compliance audit trail. False positive rate must be below 0.1% to avoid user friction.
Transaction Monitoring
Screen incoming and outgoing transactions for exposure to high-risk categories: mixing services, darknet market funds, ransomware wallets, and sanctioned entities. Chainalysis Reactor or Elliptic Investigator for manual investigation. Alert compliance team for transactions above risk threshold. File SARs with FinCEN within 30 days of detection.
Crypto Wallet Development Cost 2026
Development cost ranges from $50K for a simple single-chain wallet MVP to $300K+ for a full-featured multi-chain wallet with compliance infrastructure. Custodial builds cost 2–4× more than non-custodial due to HSM, KYC/AML, and regulatory obligations.
- ✓iOS + Android (React Native)
- ✓Single chain (ETH or Solana)
- ✓Send / receive / balance
- ✓Biometric auth
- ✓Basic transaction history
- ✓QR code send/receive
- ✓Multi-chain (ETH + BTC + Solana + L2s)
- ✓WalletConnect v2
- ✓NFT gallery + DeFi
- ✓In-wallet token swap
- ✓Push notifications
- ✓Security audit included
- ✓All non-custodial features
- ✓HSM key management
- ✓KYC/AML integration
- ✓Admin dashboard
- ✓Compliance reporting
- ✓FinCEN MSB setup support
| Component | MVP | Non-Custodial Full | Custodial |
|---|---|---|---|
| React Native app (iOS + Android) | $15K–$25K | $25K–$45K | $25K–$45K |
| Backend API + database | $8K–$15K | $15K–$25K | $35K–$60K |
| Multi-chain integration | $5K–$10K | $15K–$25K | $15K–$25K |
| HSM / MPC key management | — | — | $30K–$80K |
| KYC/AML integration | — | — | $15K–$30K |
| WalletConnect + DeFi + swap | — | $15K–$25K | $15K–$25K |
| Security audit | $10K–$20K | $15K–$30K | $25K–$50K |
| Compliance / legal fees | $3K–$8K | $5K–$15K | $20K–$60K |
The most common mistake is over-engineering on day one. Start with a non-custodial MVP ($50K–$90K) to validate product-market fit. If you hit traction, you can layer on custodial features (KYC, HSM, compliance) in a Phase 2. Non-custodial wallets ship faster, have zero regulatory overhead at launch, and are often preferred by crypto-native users anyway. Coinbase Wallet, Rainbow, and MetaMask all started non-custodial.
Account Abstraction (ERC-4337): The Future of Wallet UX
ERC-4337 enables smart contract wallets without changing the Ethereum core protocol. It unlocks gasless transactions, social recovery, session keys, and passkey signing — finally making crypto UX competitive with Web2 apps. Vitalik Buterin has called account abstraction "the most important UX improvement in Ethereum history."
Gas Abstraction (Paymaster)
A Paymaster smart contract sponsors gas fees on behalf of users. Your app pays ETH; users transact with zero gas. Integrate via Biconomy, Pimlico, or StackUp paymaster APIs. Sponsor selectively — first 5 transactions per user, or only swaps over a minimum value. ERC-20 gas payment (users pay gas in USDC) is also available via Pimlico.
Session Keys
Authorize a temporary signing key for a specific dApp with limited permissions: max spend amount, allowed contract addresses, and expiry time. Users approve once; subsequent in-game or DeFi actions happen silently without pop-ups. Essential for gaming wallets and automated DeFi strategies.
Social Recovery
Users designate guardians: trusted friends, a hardware wallet address, or an email-gated recovery service. If the phone is lost, guardians vote to rotate the signing key. No seed phrase to lose. Argent pioneered this in 2020; Safe{Core} and Kernel implement it modularly in 2026.
Multi-Sig Without Hardware
Smart contract enforces M-of-N owner signature requirements programmatically. Safe (Gnosis) is the dominant implementation with $100B+ secured. New Safe{Core} Protocol adds modular plugins for custom signing policies. No physical device required — great for DAOs and team treasuries.
Transaction Batching
Execute multiple contract calls in a single atomic UserOperation. Approve + swap in one transaction. No more approve-then-swap two-step flows. Eliminates 50% of DeFi UX friction. Also enables multi-token airdrops and complex DeFi strategies in a single click.
Passkey / WebAuthn Signing
Use Face ID or TouchID as the wallet signing key via WebAuthn hardware credential. No seed phrase. No private key visible to the user. Fully supported in modern iOS and Android browsers. Providers: Privy, Dynamic, Turnkey. The dominant passkey wallet primitive of 2026.
Biconomy — most popular paymaster + bundler SDK, battle-tested in production. Pimlico — advanced paymaster with ERC-20 gas payment support. Alchemy Account Kit — end-to-end AA stack with LightAccount smart wallet. Privy — embedded wallets with social auth, passkey, and AA — ideal for consumer apps that want to abstract wallets entirely. ZeroDev — Kernel smart account with modular plugin system and the widest chain support.
Frequently Asked Questions
Build Your Crypto Wallet with Codazz
From non-custodial mobile wallets to institutional MPC custody and ERC-4337 smart accounts — Codazz has shipped production wallets across 10+ chains. Get a free architecture review and cost estimate within 48 hours.