## Senior Blockchain Engineer – Payments, Stablecoins & Smart Contract Security
We’re looking for an experienced blockchain engineer to help design and build secure Web3 payment infrastructure with a strong focus on stablecoins, smart contract security, and reliable transaction flows.
This is not a simple token or NFT project. We need someone who understands how production blockchain payment systems behave under real-world conditions, including failed transactions, contract vulnerabilities, wallet interactions, gas management, permissions, reconciliation, and multi-chain considerations.
### What You’ll Work On
* Design and implement stablecoin payment flows using assets such as USDC/USDT
* Develop and review Solidity smart contracts
* Build secure deposit, withdrawal, settlement, and payment logic
* Integrate wallets and blockchain RPC/API infrastructure
* Implement transaction monitoring and confirmation handling
* Design authorization, signing, and permission systems
* Review contracts for security vulnerabilities and attack vectors
* Handle failed, duplicated, delayed, or reverted transactions safely
* Integrate backend services with on-chain contracts
* Improve reliability, testing, logging, and monitoring of blockchain operations
* Help define the architecture for a production-ready payment system
### Core Skills We Need
Strong experience with:
* Solidity and EVM-compatible chains
* Stablecoin integrations, especially USDC/USDT
* Web3 payments or financial transaction systems
* Smart contract security
* ethers.js / viem / Web3 libraries
* Wallet integration and transaction signing
* Node.js / TypeScript
* Blockchain RPC providers and event monitoring
* Smart contract testing with Foundry or Hardhat
* Gas optimization and transaction lifecycle management
You should understand security topics such as:
* Reentrancy
* Access-control vulnerabilities
* Signature/replay attacks
* Front-running and MEV risks
* Integer/precision issues
* Approval/allowance risks
* Upgradeable contract security
* Private-key and signer management
### Strong Plus
Experience with any of the following is valuable:
* Circle / USDC infrastructure
* Account abstraction / ERC-4337
* Safe multisig
* EIP-712 signatures
* Chainlink
* OpenZeppelin
* Cross-chain payments or bridges
* MPC or institutional wallet infrastructure
* Payment reconciliation systems
* Security audits
* DeFi protocols or fintech products
### What We’re Looking For
We prefer an engineer who has already shipped real blockchain products rather than someone whose experience is limited to tutorials or small token contracts.
When applying, please include:
1. 1 blockchain projects you personally worked on
2. Your specific responsibility on those projects
3. Links to GitHub, deployed contracts, audits, or technical work if available
4. Your experience with stablecoin/payment systems
5. One example of a serious smart contract or transaction-security problem you solved
### Engagement
We’re open to starting with a focused paid technical task and expanding into a longer-term collaboration if there’s a strong fit.
Please begin your proposal with **“Stablecoin Security”** so we know you read the full description.
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