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.