Senior Blockchain Engineer – Carbon Tokenization

Location: Remote (Preference for GMT+2 ±3 hours)
Employment: Contract (20–30 hours/week) with long-term potential
Rate: USD $90–$120/hour (depending on experience)

About the Role
We're rebuilding our Carbon Credit System—a blockchain-powered platform for issuing, certifying, trading, holding, and retiring tokenized environmental assets.
Our existing blockchain infrastructure is built on Polygon and Ethereum, where NFTs are used as digital carbon certificates and are currently integrated with OpenSea for visibility and marketplace compatibility.
As part of this rebuild, we're modernizing the platform using a more advanced Layer 2 network such as Arbitrum, while expanding it into a scalable TCU Marketplace that enables organizations, project developers, and partners to issue, trade, and retire verified carbon assets securely and transparently.

We're looking for a Senior Blockchain Engineer who can lead the blockchain architecture, rebuild the smart contract ecosystem, and continue maintaining and improving the platform after deployment.

What You'll Do
-Design and develop secure Solidity smart contracts.
-Rebuild the blockchain architecture for scalability, security, and maintainability.
-Implement ERC-721 and ERC-20/ERC-1155 token standards.
-Design the carbon token issuance and retirement mechanism.
-Maintain and improve the existing OpenSea integration for NFT-based carbon certificates.
-Design and implement the next-generation TCU Marketplace.
-Support migration from Polygon/Ethereum to a modern Layer 2 ecosystem such as Arbitrum.
-Collaborate closely with backend, frontend, and product teams.
-Optimize smart contracts for gas efficiency and security.
-Maintain, monitor, and continuously improve the blockchain system after launch.

Requirements
-Strong experience with Solidity and EVM development.
-Experience using Foundry, Hardhat, or similar frameworks.
-Deep understanding of Ethereum, Polygon, and Layer 2 ecosystems.
-Experience developing ERC-20, ERC-721, and ERC-1155 smart contracts.
-Experience integrating NFTs with marketplaces such as OpenSea.
-Strong understanding of smart contract security and audit best practices.
-Experience integrating blockchain applications with backend systems.
-Knowledge of wallet integrations (MetaMask, WalletConnect, etc.).
-Strong system architecture and problem-solving skills.

Nice to Have
-Experience with carbon markets, tokenized real-world assets (RWAs), or environmental assets.
-Experience designing NFT marketplaces or asset trading platforms.
-Knowledge of liquidity models, tokenomics, and pricing mechanisms.
-Experience with Layer 2 migration and scaling strategies.
-Familiarity with account abstraction, Zero-Knowledge technologies, or cross-chain interoperability.

What We Offer
-Competitive hourly compensation.
-Fully remote with flexible working hours.
-Opportunity to build a real-world blockchain platform with environmental impact.
-Ownership of core blockchain architecture and technical decisions.
-Long-term collaboration with an experienced engineering team.

If you're passionate about blockchain infrastructure, NFTs, tokenized environmental assets, and building scalable Web3 applications, we'd love to hear from you.