SolWill - Decentralized Dead Man's Switch for Crypto Inheritance

A Solana smart contract that enables trustless crypto inheritance using a dead man's switch mechanism. Owners deposit SOL, designate beneficiaries with percentage shares, and check in periodically. If the owner stops checking in past a configurable timeout + grace period, beneficiaries can claim their designated share on-chain — no lawyers, custodians, or centralized services required.

Live Demo

	Link
Frontend	https://solwill.pages.dev
Program (Devnet)	4bfagECyGUMHaaQF9mfTvJBpmyxTVFhzPNhb3xfTPMfF
Network	Solana Devnet

Try it out

1. Visit https://solwill.pages.dev
2. Switch your wallet (Phantom/Solflare) to Devnet
3. Get devnet SOL from sol-faucet.com or solana airdrop 2
4. Connect wallet and create your first will

How It Works

1. Owner creates a will with a timeout period (e.g., 90 days) and grace period (e.g., 7 days)
2. Owner deposits SOL into a program-controlled vault
3. Owner adds beneficiaries with percentage shares (in basis points, 10000 = 100%)
4. Owner checks in periodically to reset the dead man's switch timer
5. If the owner stops checking in and timeout + grace period elapses, beneficiaries can claim their share
6. Each beneficiary claims independently — no coordination required

Architecture

Account Structure

┌─────────────────────────────────────────────┐
│                Will Account (PDA)           │
│  seeds: ["will", owner_pubkey]              │
├─────────────────────────────────────────────┤
│  owner: Pubkey                              │
│  timeout_seconds: u64                       │
│  grace_period: u64                          │
│  last_checkin: i64                          │
│  created_at: i64                            │
│  total_deposited: u64                       │
│  total_withdrawn: u64                       │
│  total_claimed: u64                         │
│  is_paused: bool                            │
│  is_closed: bool                            │
│  bump: u8                                   │
│  vault_bump: u8                             │
│  beneficiaries: Vec<Beneficiary>            │
│    ├── address: Pubkey                      │
│    ├── share_bps: u16                       │
│    └── has_claimed: bool                    │
└─────────────────────────────────────────────┘

┌─────────────────────────────────────────────┐
│              Vault Account (PDA)            │
│  seeds: ["vault", will_pubkey]              │
├─────────────────────────────────────────────┤
│  Holds deposited SOL                        │
│  Controlled by program via PDA signature    │
└─────────────────────────────────────────────┘

Instructions (13 total)

Instruction	Caller	Description
initialize	Owner	Create a new will with timeout and grace period
deposit	Owner	Deposit SOL into the vault
add_beneficiary	Owner	Add a beneficiary with share in basis points
remove_beneficiary	Owner	Remove a beneficiary from the will
update_beneficiary	Owner	Update a beneficiary's share percentage
checkin	Owner	Reset the dead man's switch timer
withdraw	Owner	Withdraw SOL (only if not timed out)
update_timeout	Owner	Update timeout and/or grace period
pause_will	Owner	Pause the will (blocks all operations)
unpause_will	Owner	Unpause the will and reset timer
transfer_ownership	Owner	Transfer will ownership to another address
close_will	Owner	Close the will and reclaim all funds + rent
claim	Beneficiary	Claim share after timeout + grace period

Events

All instructions emit events for off-chain indexing:

• WillInitialized — Will created
• SolDeposited — SOL deposited into vault
• BeneficiaryAdded — New beneficiary added
• BeneficiaryRemoved — Beneficiary removed
• BeneficiaryShareUpdated — Beneficiary share changed
• OwnerCheckedIn — Owner performed check-in
• SolWithdrawn — SOL withdrawn from vault
• ShareClaimed — Beneficiary claimed their share
• WillPausedEvent — Will paused
• WillUnpausedEvent — Will unpaused
• WillClosed — Will closed
• TimeoutUpdated — Timeout period changed
• GracePeriodUpdated — Grace period changed
• OwnershipTransferred — Ownership transferred

Error Codes

Error	Description
NotAuthorized	Non-owner calling owner-only instruction
ShareOverflow	Total shares would exceed 100% (10000 bps)
TimedOut	Owner tries to withdraw after timeout elapsed
TooEarly	Beneficiary claims before timeout + grace period
NotBeneficiary	Caller not in beneficiaries list
AlreadyClaimed	Beneficiary already claimed their share
BeneficiaryAlreadyExists	Duplicate beneficiary address
MaxBeneficiariesReached	Maximum 10 beneficiaries
ZeroDeposit	Deposit amount is zero
ZeroWithdraw	Withdrawal amount is zero
InsufficientBalance	Vault balance too low for withdrawal
ZeroShare	Share basis points is zero
TimeoutTooShort	Timeout less than 1 day (86400s)
GracePeriodTooShort	Grace period less than 1 hour (3600s)
WillPaused	Action attempted while will is paused
WillClosed	Action attempted on a closed will
WillNotPaused	Unpause attempted while will is not paused
BeneficiaryNotFound	Beneficiary address not found in will
UnclaimedSharesExist	Cannot close will with unclaimed shares after timeout
CannotUpdateAfterTimeout	Cannot modify settings after timeout
SameOwner	Transfer ownership to same address

Access Control

Owner only:           initialize, deposit, add_beneficiary, remove_beneficiary,
                      update_beneficiary, checkin, withdraw, update_timeout,
                      pause_will, unpause_will, transfer_ownership, close_will

Listed beneficiary:   claim (only after timeout + grace period)

Tech Stack

Component	Technology
Smart Contract	Rust, Anchor v0.31.1
Frontend	Next.js 16, React 19, TypeScript
Styling	Tailwind CSS v4, Framer Motion
Wallet Integration	Solana Wallet Adapter
Deployment	Cloudflare Pages (frontend), Solana Devnet (program)

Prerequisites

• Rust (stable toolchain + solana toolchain)
• Solana CLI v2.x
• Anchor v0.31.x
• Node.js v18+
• Yarn

Setup

# Clone the repository
git clone <your-repo-url>
cd solwill

# Install dependencies
yarn install

# Build the program
anchor build

# Run tests
anchor test

Frontend Development

cd app

# Install frontend dependencies
npm install

# Run development server
npm run dev

# Build for production
npm run build

Configuration

The will supports the following configurable parameters:

Parameter	Minimum	Description
timeout_seconds	86400 (1 day)	How long before the dead man's switch activates
grace_period	3600 (1 hour)	Additional buffer after timeout before claims open
share_bps	1	Beneficiary share in basis points (10000 = 100%)
Max beneficiaries	—	10 per will

Project Structure

solwill/
├── programs/solwill/src/
│   ├── lib.rs                          # Program entry point
│   ├── errors.rs                       # Custom error codes
│   ├── events.rs                       # Event definitions
│   ├── state/
│   │   ├── mod.rs
│   │   └── will.rs                     # WillAccount and Beneficiary structs
│   └── instructions/
│       ├── mod.rs
│       ├── initialize.rs               # Create will
│       ├── deposit.rs                  # Deposit SOL
│       ├── add_beneficiary.rs          # Add beneficiary
│       ├── remove_beneficiary.rs       # Remove beneficiary
│       ├── update_beneficiary.rs       # Update beneficiary share
│       ├── checkin.rs                  # Owner check-in
│       ├── withdraw.rs                 # Withdraw SOL
│       ├── claim.rs                    # Beneficiary claim
│       ├── close_will.rs              # Close and reclaim
│       ├── update_timeout.rs           # Update timeout/grace
│       ├── pause_will.rs              # Pause/unpause
│       └── transfer_ownership.rs       # Transfer ownership
├── app/                                # Next.js frontend
│   ├── src/
│   │   ├── app/                        # Pages and layout
│   │   ├── components/                 # UI components
│   │   ├── hooks/                      # useSolWill hook
│   │   └── utils/                      # Constants, IDL, types
│   └── package.json
├── tests/
│   └── solwill.ts                      # Integration tests (55 tests)
├── Anchor.toml
├── Cargo.toml
└── package.json

Testing

# Run all tests
anchor test

# Run tests with logs
anchor test -- --features "anchor-debug"

Test Coverage (55 tests)

• Initialize — Will creation with valid parameters
• Deposit — SOL deposits, total tracking, zero amount rejection
• Add Beneficiary — Adding with shares, duplicate prevention, overflow prevention, zero share rejection
• Update Beneficiary — Share updates, overflow validation, non-existent beneficiary
• Remove Beneficiary — Removal, non-existent beneficiary
• Update Timeout — Timeout/grace period updates, minimum validation
• Check In — Timer reset verification
• Pause/Unpause — State toggling, 10 blocked operations while paused (deposit, add/remove/update beneficiary, withdraw, checkin, update timeout, transfer ownership)
• Withdraw — SOL withdrawal, zero amount, insufficient balance
• Claim — Pre-timeout rejection, non-beneficiary rejection
• Transfer Ownership — Same-address rejection, zero address rejection
• Close Will — Will closure with fund recovery, re-initialization, deposit-after-close rejection
• Authorization — Non-owner rejection for all 7 owner-only operations
• Max Beneficiaries — Adding 10 beneficiaries, 11th rejected
• Account State — Full field verification, vault balance check

Deployment

# Configure for devnet
solana config set --url devnet

# Airdrop SOL for deployment
solana airdrop 2

# Build and deploy
anchor build
anchor deploy --provider.cluster devnet

# Verify deployment
solana program show 4bfagECyGUMHaaQF9mfTvJBpmyxTVFhzPNhb3xfTPMfF --url devnet

Security Considerations

• PDA-controlled vault: No individual can withdraw without meeting program conditions
• Basis point validation: Total shares cannot exceed 10000 (100%)
• Double-claim prevention: has_claimed flag per beneficiary
• Time-based access control: Claims only after timeout + grace period
• Pause mechanism: Owner can freeze operations in emergencies
• Pause-blocking: All state-changing operations blocked when paused
• Overflow protection: saturating_add used for cumulative counters
• Zero address validation: Ownership cannot be transferred to zero address
• Rent-exempt protection: Withdrawals and claims preserve minimum rent balance
• CPI with PDA signer: Vault transfers use system program CPI with PDA seeds

License

MIT