Milestone Escrow
The client locks the full budget up front, split into milestones. Funds move only on release, arbiter decision or cancellation.
Solidity 0.8.28OpenZeppelin v5ETH / ERC-20
Token + Vesting + Staking
Token-launch toolkit: capped ERC-20, cliff + linear vesting and staking rewards
ERC-20EIP-2612OpenZeppelin v5Foundry
What it is
SigmaToken is an ERC-20 with a hard cap, EIP-2612 permit (gasless approvals), burnability and two-step ownership — the owner can mint only up to the cap. TokenVesting holds tokens for many beneficiaries; each schedule has a start, a cliff, a duration and a revocable flag, and is fully funded when it is created.
StakingRewards lets users stake one token and earn another (or the same) at a fixed rate over a reward period. It uses O(1) reward-per-token accounting, so gas costs don't grow with the number of stakers, and rewards are pulled into the contract before they are promised.
The business problem
A token launch needs supply discipline, credible lock-ups for team and investors, and fair holder incentives. Custom, unaudited implementations of these patterns are a common source of exploits — broken reward maths, unfunded reward promises and admin backdoors.
How it works
- 1
SigmaToken is deployed with a hard cap; the owner can mint only up to it.
- 2
The owner creates vesting schedules (start, cliff, duration, amount, revocable). Tokens are pulled into the contract immediately.
- 3
Nothing vests before start + cliff; afterwards tokens vest linearly until the end of the duration. Beneficiaries call
release()at any time. - 4
For revocable schedules,
revoke()keeps the vested part claimable and returns only the unvested remainder. - 5
The owner funds a staking reward period with
notifyRewardAmount(); stakers earn pro rata and can stake, withdraw, claim or exit at any time.
Security measures
- Hard cap enforced in _update, so it applies to every mint path
- Two-step ownership on all three contracts
- Vesting fully collateralised; invariant balance == allocated − released checked by fuzzing
- Fair revocation: vested tokens can never be clawed back
- Rewards pulled on notify — no unfunded promises; solvency invariants
- recoverERC20 can never withdraw the staking or reward token
- nonReentrant on value-moving functions, SafeERC20 throughout
Features
- Capped ERC-20 with EIP-2612 permit
- Cliff + linear vesting for many beneficiaries
- Per-schedule revocable flag
- Synthetix-style staking rewards with O(1) maths
- Reward-period rollover
Typical use cases
- Token generation events for DAOs, games and loyalty programmes
- Transparent team, advisor and investor vesting
- Staking-reward and liquidity campaigns
Known limitations
Reward duration can only be changed between reward periods.
Other showcase contracts
SigmaNFT Collection
A fair NFT launch: allowlist and public phases, per-wallet limits, immutable max supply, ERC-2981 royalties and a delayed reveal.
ERC-721ERC-2981Merkle proofs
Gold-Backed Token (RWA)
Backing becomes a precondition of minting: tokens can only be minted if the reported gold reserve covers the new total supply.
ERC-20AccessControlProof of reserve
Standards: Solidity 0.8.x, OpenZeppelin, Foundry tests with fuzzing, Slither static analysis, verified source. 223 tests · 100% coverage · Slither-analysed.
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