BACKEND/BLOCKCHAIN ENGINEER

About COINYEX

COINYEX is building the next generation of financial technology centered around TUX WALLET, a Web3 wallet ecosystem combining digital assets, blockchain, Web3, payment services, AI, and other emerging technologies.

We are looking for a Backend / Blockchain Engineer who can work beyond conventional backend development and contribute to real-world blockchain and Web3 infrastructure.

This is an opportunity to become a core technical contributor to the long-term development of our platform.

? What We’re Looking For

We are looking for someone who:

* Has professional backend development experience

* Has experience designing and developing APIs

* Understands database design

* Has practical blockchain / Web3 knowledge

* Can work confidently in Linux and Git/GitHub environments

* Can communicate technical matters in English

* Is comfortable researching and learning new technologies independently

* Thinks about security, scalability, reliability, and failure scenarios, not just functionality

What You’ll Do

You will be involved in designing, developing, and maintaining backend and blockchain-related systems, including:

* Build and maintain the TUX WALLET backend

* Design and develop REST APIs and WebSocket services

* Work with databases, caching, queues, and asynchronous processing

* Integrate Ethereum and other EVM-compatible blockchains

* Work with RPC providers, blockchain transactions, gas, nonces, and confirmations

* Integrate ERC-20 tokens and smart contracts

* Process and monitor on-chain data and blockchain events

* Contribute to DEX / Swap integrations

* Work with cross-chain and omnichain technologies

* Integrate external APIs including payment, KYC, on/off-ramp, exchange, banking, and card services

* Build secure, scalable, and highly reliable financial infrastructure

* Implement monitoring, logging, authentication, authorization, and security controls

? Technology Stack

Experience with some of the following technologies is highly valued:

Backend

* Node.js / TypeScript

* Python

* NestJS

* PostgreSQL / MySQL

* Redis

* REST / WebSocket APIs

* ⁠PHP

Blockchain / Web3

* Ethereum / EVM

* Solidity

* Ethers.js / Web3.js / Viem

* Smart Contract Integration

* ERC-20

* RPC / On-chain Data

* Transaction Monitoring

* Blockchain Indexing

DEX / Swap

* Uniswap

* 1inch

* KyberSwap

* LI.FI

* 0x

* ParaSwap

* GMX

* ChangeNOW

* LayerZero

* Chainlink CCIP

* Wormhole

* Bridges / Cross-chain Messaging

* Omnichain Architecture

Infrastructure

* AWS

* Docker

* CI/CD / GitHub Actions

* Linux

* Load Balancing

* Monitoring / Observability

? Security Matters

Because TUX WALLET operates in the financial and digital-asset space, security is a major priority.

We value experience with:

* API security

* JWT / OAuth

* Encryption

* Secrets management

* Rate limiting

* OWASP principles

* Access control

* Audit logs

* Private key security concepts

* Multisig

* Smart contract risks

* Token approval risks

* Transaction and signature verification

? AI Experience — Bonus

AI experience is not mandatory, but candidates with experience in the following will have an advantage:

* LLMs

* OpenAI / Claude / Gemini APIs

* AI Agents

* MCP

* Function / Tool Calling

* RAG

* Vector Databases

* Agent Orchestration

* Multi-Agent Systems

We are particularly interested in engineers who understand how AI agents can safely interact with APIs and blockchain functions through appropriate permissions and execution controls.

Please refer to job description.