Smart Contracts
- Solidity (0.8.x)
- Hardhat & Foundry
- OpenZeppelin upgradeable (UUPS)
- Chainlink VRF & Automation
- ERC-20 / ERC-721 / ERC-1155
Available for new Web3 projects
I build trust-minimized smart contracts & the dApps around them.
I'm Joseph — an independent Web3 developer working at the intersection of Solidity, DeFi, and frontend engineering. I ship audited contracts, clean React interfaces, and production-grade tooling for protocols that actually need to work on mainnet.
- 5+Years building software
- 5Shipped Web3 projects
- 100%On-chain & verified
About
Independent. Focused. Shipping on mainnet.
I work as a one-person team — design, contracts, frontend, deployment, and ops.
Every project I ship is end-to-end my responsibility, from the
SafeERC20 import in a Solidity file to the deploy script that
pushes the dApp behind a CDN.
I focus on reliable, auditable code. The proof is the GitHub history, the verified contract address on BscScan, and the running product you can use today — not slide decks.
When I'm not writing contracts I'm reading post-mortems on DeFiHackLabs, studying real exploits, and turning them into checklists for my own deployments.
Stack
What I work with every day.
DeFi & Protocols
- AMMs & liquidity design
- Lottery / yield / staking primitives
- Memecoin launch mechanics
- Pull-payment patterns
- Front-running mitigation
Frontend
- React / Next.js
- TypeScript
- HTML5 / CSS3 / Tailwind
- ethers.js / wagmi / viem
- WalletConnect & RainbowKit
Security & Tooling
- Slither & Mythril
- Fuzz testing (Echidna, Foundry)
- AI-assisted contract review
- BscScan / Etherscan verification
- Hostinger / VPS deployments
Selected work
Things I built and shipped.
Live · B2B SaaS
SecureFlow
AI-powered smart contract & security questionnaire engine.
SecureFlow continuously monitors Ethereum and Arbitrum for newly deployed contracts and runs them through a multi-layer AI pipeline (GPT-4 / Claude + Slither) to surface 15+ classes of vulnerabilities — reentrancy, access control, oracle manipulation, and more. The same engine powers an enterprise B2B mode that auto-answers vendor security questionnaires from your own docs, with citations.
- Python
- Slither
- OpenAI / Anthropic
- SQLite
- SaaS dashboard
Open source · Reference contract
MeowCoin (MEOW)
Solidity ERC-20 reference: trading gate, anti-whale limits, configurable tax-on-transfer.
A small, deliberately-readable ERC-20 written for interview practice and as a starting point
for memecoin-style launches. Implements three optional, owner-gated features through a single
OpenZeppelin v5 _update hook: a one-way trading flag that blocks sniper bots
until launch, basis-point caps on per-tx and max-wallet balances, and a hardcapped (5%) tax
routed to a treasury — with a 256-run Foundry fuzz suite proving the maxTx invariant holds.
README documents every feature intentionally left out (reflection, anti-MEV, blacklists,
upgradeability) and why.
- Solidity 0.8.24
- Foundry
- OpenZeppelin v5
- ERC-20
- Fuzz testing
Open source · DeFi reference
CatnipFarm
Single-pool ERC-20 staking with constant reward emission (Synthetix pattern).
Solidity reference for the most-copied DeFi primitive on Ethereum — the per-share
reward accumulator. Stake any ERC-20, earn any ERC-20 at a constant per-second emission
rate. Every action (stake, withdraw, claim, top-up) is O(1) regardless of staker count
because each user records the value of the global accumulator at their last interaction
and computes pending reward as stake × (current_index − debt_index).
17-test Foundry suite including a 256-run conservation fuzz that proves total earned
never exceeds total emitted.
- Solidity 0.8.24
- Foundry
- OpenZeppelin v5
- SafeERC20
- ReentrancyGuard
- Fuzz testing
Open source · Token launch primitive
PawClaim
Solidity Merkle-tree airdrop: claim ERC-20 distributions via Merkle proof.
The dominant pattern for token-launch airdrops on Ethereum (Uniswap, ENS, Optimism,
Arbitrum all use this). Each leaf is keccak256(account, amount); the
contract stores only the 32-byte Merkle root and verifies O(log N)
proofs at claim time. Includes hard-coded immutable claim deadline (no rug),
ReentrancyGuard, double-claim protection, and owner-only sweep of
unclaimed balance after the window. 10-test Foundry suite that builds an in-memory
Merkle tree to verify every claim path end-to-end.
- Solidity 0.8.24
- Foundry
- OpenZeppelin v5
- Merkle proofs
- SafeERC20
- ReentrancyGuard
Open source · Token launch primitive
CatVesting
Solidity linear vesting with cliff and optional revoke — for team / investor allocations.
Linear ramp from cliff to end, with an optional revoke() that
snapshots the vested amount at the moment it's called — preventing the
classic vesting bug where pulling unvested tokens out shifts the curve and
silently shortchanges the beneficiary. The README documents every design decision
(no off-schedule top-ups, no upgradeability, immutable beneficiary) and what you
should change before production. 19-test Foundry suite including a 256-run fuzz
proving vestedAmount() is monotonically non-decreasing.
- Solidity 0.8.24
- Foundry
- OpenZeppelin v5
- SafeERC20
- Fuzz testing
FAQ
Common questions.
What kind of Web3 work do you take on?
Smart contract development (Solidity, Hardhat, Foundry), DeFi protocol design, dApp frontends (React / Next.js / wagmi / ethers), audit prep, and full-stack launches. I take on a small number of projects per quarter so I can ship them end-to-end.
Are you available for full-time roles?
Yes. Open to full-time, contract, freelance, or advisory engagements. Remote-first, US-based.
What chains have you shipped on?
Primarily Ethereum, Arbitrum, and BNB Smart Chain (SecureFlow scanning targets). Comfortable with any EVM chain.
Can I see code samples or audit reports?
Yes — verified contract addresses on BscScan, public GitHub repos, and internal audit summaries are all available on request via email.
Do you also do non-Web3 React work?
Yes. 5+ years of React / Next.js / TypeScript experience and regularly take on general frontend or full-stack JavaScript work.
Contact
Have a contract that needs to ship?
I take on a small number of Web3 builds per quarter — protocol design, audit prep, dApp frontends, or full-stack launches. If that sounds like what you need, send me a note.