Eric Johnson

eric.johnson.dev123@gmail.com | https://Eric-Johnson-1.github.io/Portfolio | https://github.com/Eric-Johnson-1

Summary

Web3 Full-Stack Software Engineer who has architected 30+ Solidity smart contracts and shipped 4+ production-grade dApps across DeFi, NFT, DAO governance, and healthcare. Backed by strictly enforced security standards, establishing 100% on-chain core mechanics verification via comprehensive Foundry test suites (650+ invariant and fuzz tests). 4+ years of remote Web3 experience spanning EIP-7201 UUPS-upgradeable contract systems, ERC-4337 Account Abstraction with gasless onboarding, and ERC-5192 Soulbound Token architectures, plus 2 years of Web2 full-stack development. Deep expertise in building censorship-resistant systems (Merkle proof + IPFS anti-censorship), on-chain governance (Governor + Timelock + quadratic funding), and gas-optimized storage layouts. Seeking to bring end-to-end blockchain engineering depth to a team building impactful, user-centric decentralized infrastructure.

Technical Skills

Blockchain & Smart Contracts: Solidity, Foundry, OpenZeppelin, UUPS Proxy (EIP-7201 Namespaced Storage), ERC-4337 (Account Abstraction — Smart Account + Paymaster + Factory), ERC-5192 (Soulbound Tokens), ERC-7821 (Batched Execution), ERC-1271 (On-chain Signature Validation), ERC-721A, EIP-712 (Typed Data Signatures), ERC-1155, ERC-20, Create2 Deterministic Deployment, Merkle Proof Verification, Quadratic Funding (CLR), DAO Governance, Gas Optimization, NFT Marketplace Architecture

Frontend & Wallet Integration: TypeScript, Next.js (App Router), React, Wagmi, Viem, RainbowKit, ConnectKit, Tailwind CSS, Radix UI, Framer Motion, Zustand, TanStack Query

Backend & Infrastructure: Bun, Hono, Node.js, Express.js, Drizzle ORM, PostgreSQL, MongoDB, The Graph (Subgraph), IPFS, Upstash Redis, Docker, Zod (Schema Validation)

Tools & DevOps: Turborepo (Monorepo), Git, GitHub Actions (CI/CD), Satori + Sharp (Dynamic SVG → PNG/WebP Rendering)

Experience

Web3 Full-Stack Software Engineer | Remote - Bianjie.AI

2023.02 - present
Core developer on a production enterprise-grade IDO (Initial DEX Offering) platform with staking-based allocation, LP yield farming, and on-chain token vesting. Turborepo monorepo across 4 workspaces (web, api, contracts, subgraph) running on Bun.
  • Architected 5 UUPS-upgradeable Solidity smart contracts (SalesFactory, Sale, AllocationStaking, FarmingNBL, Vesting) with EIP-7201 namespaced storage layouts, ReentrancyGuard, and Pausable emergency circuit-breakers — enabling upgrade-safe infrastructure with zero storage collision risk.
  • Engineered a Create2 deterministic clone deployment system via `Clones.cloneDeterministic`, enabling predictable Sale contract addresses before deployment and gas-efficient factory-pattern IDO launches.
  • Designed a Merkle proof + IPFS anti-censorship whitelist architecture: backend generates Merkle trees, uploads complete whitelist JSON to IPFS, and stores roots on-chain. Frontend implements TanStack Query dual-source fallback (API → IPFS + on-chain root), ensuring 100% trustless participation even if the centralized backend goes offline.
  • Built a MasterChef V2-style LP farming contract (`FarmingNBL`) with multi-pool support, time-weighted reward accumulation, external `IRewarder` plugin interface, duplicate LP token detection, and balance-capped safe distribution.
  • Implemented per-user Vesting contract deployment on token claim: Sale contract dynamically deploys individual `Vesting` contracts with configurable linear release schedules, SafeERC20 transfers, and owner-recoverable `recoverERC20` for accidentally sent tokens.
  • Developed the Hono + Drizzle ORM backend (TypeScript/Bun) with RESTful project CRUD, IPFS upload pipeline, Zod schema validation, and PostgreSQL persistence with `onConflictDoUpdate` upsert resolution for atomic snapshot updates.
  • Implemented on-chain safety invariant checks: Sale contract verifies `IERC20.balanceOf(address(this)) >= tokensSold + tokensToBuy` (C5), and `withdrawLeftoverTokens` uses **`min(unsold, balance)` safe withdrawal pattern** (H2).
  • Deployed a Graph Protocol subgraph indexing 4 entity types with `@derivedFrom` reverse-lookup relationships — replacing expensive on-chain enumeration with real-time event-indexed queries.
  • Built the Next.js frontend with Wagmi / Viem for type-safe contract interactions, reactive on-chain state updates, and managed Docker Compose for PostgreSQL and environment-driven chain configuration.

Web3 Full-Stack Software Engineer | Remote - TheOne.art

2022.02 - 2023.02
  • Engineered a high-performance NFT marketplace supporting primary issuance and secondary trading, leveraging ERC721A to achieve gas-optimized batch minting operations.
  • Architected a decentralized order book using EIP-712 typed data signatures, enabling gasless off-chain maker order placements with atomic on-chain taker matching.
  • Developed comprehensive Subgraph (The Graph) indexing for complex marketplace events (listings, bids, sales), reducing frontend query latency by removing on-chain RPC bottlenecks.
  • Designed an automated hybrid storage pipeline utilizing IPFS for decentralized metadata pinning combined with a robust Node.js/Express.js backend.
  • Implemented diverse wallet standard support with Ethers.js, driving strict security patterns including `ReentrancyGuard` and pull-over-push fund distribution mechanisms.

Personal Projects

💚 HopeDAO — Decentralized Mutual Aid Crowdfunding DAO

GitHub
A full-stack DAO platform on Base L2 enabling transparent, community-governed mutual aid crowdfunding with milestone-based fund release and quadratic funding matching.
  • Architected 14 Solidity source files across 5 modules: core campaign management, DAO governance, ERC-20 governance token, ERC-1155 Soulbound NFTs, and an ERC-4337 Account Abstraction system.
  • Engineered a full ERC-4337 smart account stack: `HopeAccount` (UUPS + ERC-7821 batched execution + ERC-1271 off-chain signature validation) + Factory (Create2) + Paymaster (per-user daily limits, exact `postOp` gas refunds).
  • Implemented quadratic funding (CLR matching) algorithm in a Solidity library using Babylonian-method integer `sqrt` with 1e18 fixed-point precision.
  • Designed a verifier staking & reputation system (`VerifierRegistry`) with automated cooldowns, governance slash functions, and on-chain reputation scoring.
  • Built milestone-based fund release with IPFS evidence submission, DAO vote verification, and treasury fee deduction (max 10%).
  • Achieved 249 tests passing (10 suites, including invariant and fuzz tests) with Foundry, covering Governor proposals, Paymaster validation, and slashing scenarios.
  • Tech: Solidity · Foundry · ERC-4337 · Next.js · Wagmi · Viem · Hono · Drizzle ORM · PostgreSQL · Bun

💉 MedBadge — Blockchain Vaccination Record SBT System

GitHub
A decentralized vaccination record management platform turning immunization records into tamper-proof Soulbound Tokens (ERC-5192) on Base L2 with GDPR-compliant privacy architecture.
  • Engineered a storage-slot-optimized `VaccinationRecord` struct packing 5 fields into 35 bytes / 2 EVM storage slots, achieving ~60% gas savings versus naïve `uint256` implementations.
  • Designed a hybrid on-chain/off-chain architecture with AES-256-GCM encryption for PII on IPFS, fully GDPR-compliant via unpin + key destruction for the right to erasure.
  • Implemented ERC-5192 Soulbound semantics by overriding `_update()` to block transfers, emitting `Locked` events, achieving ERC-721 compatibility without transferability.
  • Built a two-tier institution-based registrar management system (`Ownable2Step`): Phase 2 delegates to admins with automatic registrar deactivation via cascading `active` flags.
  • Engineered batch revocation (up to 200/tx) utilizing `delete revocationReason` to reclaim storage slots and earn Gas refunds, maintaining a full on-chain audit trail.
  • Built dynamic badge rendering via Satori + Sharp (SVG → PNG/WebP). Integrated The Graph, intentionally omitting ERC-721 Enumerable to save ~20,000 gas per mint.
  • Achieved 119 tests passing (unit + invariant + fuzz) with Foundry.
  • Tech: Solidity · Foundry · ERC-5192 · ERC-721 · Next.js · Wagmi · Hono · Bun · The Graph · IPFS

Community & Interests

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