Web3 / DeFi

DeFi Yield Protocol: $2.1M TVL in 30 Days, Audit Passed with 0 Critical Findings

8-week build
Anonymized — details changed to protect the client

$2.1M

TVL in first 30 days

0

Critical or high audit findings

$750K

Seed round secured

8 wks

Idea to production

The Founder's Problem

“Marcus” (name changed) had a clear vision: a yield optimization protocol that automatically routes user deposits into the highest-yielding liquidity pools across Arbitrum, rebalancing daily using on-chain price feeds. He understood DeFi mechanics deeply — he had been a liquidity provider and yield farmer for two years — but had zero Solidity experience.

Two blockers stood in his way: cost and risk. He had been quoted $200K–$280K by other agencies with 6–9 month timelines. More critically, he knew that a smart contract bug in DeFi isn't just embarrassing — it can result in total loss of user funds. He needed a team that understood both the economics and the security implications.

“I needed someone who understood both the Solidity and the DeFi side. Most dev shops could write the code. Very few understood why certain design choices would be exploitable. Idea to MVP got both.”

— Marcus, DeFi Founder (anonymized)

Our Solution

We built a production-grade DeFi protocol using the ERC-4626 tokenized vault standard, which gave the protocol instant composability with the wider Arbitrum DeFi ecosystem. The vault accepts USDC deposits, routes capital to yield strategies, and issues share tokens that represent the depositor's proportional claim.

Smart Contract Architecture

  • ERC-4626 compliant vault contract with deposit, withdraw, and redeem functions
  • Strategy contracts per yield source (Aave v3, GMX GLP, Camelot LP) with allocation weights
  • Chainlink Data Feeds integration for real-time price oracle — no reliance on manipulatable spot prices
  • Emergency pause mechanism and withdrawal queue for adverse market conditions
  • Role-based access control (OpenZeppelin) with timelock on strategy rebalances
  • 100% test coverage with Hardhat — 143 unit and integration tests

Frontend dApp

  • Next.js 14 app with wagmi + viem for wallet connection (MetaMask, WalletConnect, Coinbase Wallet)
  • Real-time TVL, APY, and yield breakdown dashboard using The Graph subgraph
  • Transaction history with on-chain proof links to Arbiscan
  • Mobile-responsive design with dark mode

Tech Stack

Solidity 0.8.23HardhatOpenZeppelinChainlink Data FeedsThe GraphNext.js 14wagmi / viemTailwind CSSArbitrum OneIPFS (metadata)Vercel

Timeline (8 Weeks)

Week 1

DeFi Architecture Design

Mapped the yield strategy logic, chose ERC-4626, designed the strategy contract interface, set up Hardhat environment with forked Arbitrum for testing.

Week 2

Core Vault Contract

Built and tested the ERC-4626 vault. Implemented deposit, withdraw, redeem flows. 43 unit tests passing.

Week 3

Strategy Contracts & Chainlink

Built Aave v3 and GMX strategy contracts. Integrated Chainlink Data Feeds for price validation. Added rebalance logic with timelock.

Week 4

Security Hardening & Test Suite

Added reentrancy guards, emergency pause, role-based access. Built integration tests simulating flash loan attacks and oracle manipulation. 100 tests total.

Week 5

Audit Preparation & Frontend Start

Prepared audit documentation (natspec comments, architecture diagram, threat model). Started dApp frontend with wallet connection.

Week 6

dApp Development

Built TVL dashboard, deposit/withdraw flows, transaction history. Deployed The Graph subgraph on Arbitrum.

Week 7

Audit & Fixes

Smart contract audit conducted by external firm. Received 0 critical, 0 high, 2 medium, 4 low findings. Fixed all medium findings, documented low-risk acceptances.

Week 8

Mainnet Deploy & Launch

Deployed to Arbitrum mainnet. Listed on DeFiLlama. Launched with founder's community — $200K TVL in 48 hours.

Results (90 Days Post-Launch)

$2.1M

TVL reached within 30 days of mainnet launch

0

critical or high severity findings in smart contract audit

$750K

seed round secured — investors cited audit result and TVL traction

DeFiLlama

listed within 48 hours of launch, driving organic discovery

143

automated tests — 100% smart contract coverage

2 medium

audit findings — both fixed before launch; 0 incidents in 90 days

What Made This Work

Choosing ERC-4626 was the right call. It meant the protocol was immediately compatible with aggregators like Yearn and Beefy, giving it instant distribution without additional integration work. DeFiLlama listing was automatic because they support ERC-4626 natively.

The Chainlink oracle decision — over using a DEX spot price — was also pivotal. It eliminated the single largest attack vector in DeFi yield protocols: price manipulation via flash loans. The auditors specifically flagged this as a strength, which contributed to the clean audit result.

Building a DeFi Protocol or Web3 Product?

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