Job Description:
 
We are looking for an experienced Crypto Custody Engineer to join our Wallex B2B engineering team and help build secure, scalable, and reliable digital asset infrastructure.

 

In this role, you will design and develop components responsible for managing cryptocurrency custody operations, blockchain connectivity, wallet services, and transaction processing.

 

You will work on systems that require:

●        High Security

●        Strong Reliability

●        Transaction Integrity

●        Operational Transparency

●        Auditability

You will collaborate with Backend Engineers, Security Teams, DevOps, Infrastructure, and Product teams to transform blockchain technology into reliable financial products.
 
Key Responsibilities:
 
●        Design, develop, and maintain Crypto Custody services and blockchain infrastructure.

●        Build and maintain secure wallet management systems.

●        Implement blockchain integrations with different networks and digital assets.

●        Develop transaction lifecycle management including:

○        Transaction Creation

○        Validation

○        Broadcasting

○        Confirmation Tracking

○        Failure Handling

●        Design and implement secure deposit and withdrawal workflows.

●        Build blockchain monitoring and event-processing systems.

●        Integrate and maintain blockchain nodes, APIs, and third-party blockchain services.

●        Develop backend services supporting digital asset operations.

●        Improve transaction reliability through:

○        Retry Mechanisms

○        Failure Recovery

○        Reconciliation Processes

○        Monitoring

●        Participate in architecture decisions for custody systems and blockchain infrastructure.

●        Implement security best practices for:

○        Private Key Protection

○        Access Control

○        Transaction Authorization

○        Secure Communication

●        Perform Code Reviews and contribute to engineering standards.

●        Investigate and resolve blockchain-related production incidents.

●        Collaborate with Security, DevOps, Infrastructure, and Product teams.

●        Maintain technical documentation for blockchain services and operational processes.
 
Key Requirements:
 
●        5+ years of professional software engineering experience.

●        2+ years of practical experience working with blockchain or digital asset systems.

●        Strong backend development experience with:

○        Python

○        Django

○        REST API Development

●        Strong understanding of:

○        Blockchain Architecture

○        Transaction Lifecycle

○        Wallet Systems

○        Blockchain Networks

○        Digital Asset Management

●        Experience working with one or more blockchain ecosystems:

○        Bitcoin

○        Ethereum

○        EVM-Compatible Networks

○        Other Layer 1 / Layer 2 Networks

●        Experience with:

○        Blockchain APIs

○        Node Integration

○        Transaction Monitoring

○        Smart Contract Interaction

●        Strong understanding of cryptographic concepts:

○        Public / Private Keys

○        Digital Signatures

○        Address Management

○        Key Security Principles

●        Experience designing secure backend systems with:

○        Authentication

○        Authorization

○        Access Control

○        Audit Logging

●        Strong experience with:

○        PostgreSQL

○        Redis

○        Message Queues

○        Distributed Systems

●        Experience with:

○        Docker

○        Git

○        CI/CD Pipelines

○        Production Deployment

●        Ability to design systems requiring:

○        High Availability

○        Security

○        Reliability

○        Fault Tolerance

●        Strong debugging and problem-solving skills for complex technical issues.
 
Key Competencies:
 
Bachelor's degree or higher in:

●        Computer Engineering

●        Software Engineering

●        Electrical Engineering

●        Cryptography

●        Related fields

*Graduating from top-ranked universities is a plus.

Previous experience working in:

●        Crypto Exchanges

●        Digital Asset Custody Providers

●        Blockchain Infrastructure Companies

●        Fintech Platforms

●        Payment Systems

●        Large-scale Technology Companies

Experience building production systems requiring:

●        High Security

●        Asset Protection

●        High Availability

●        Scalability

●        Operational Reliability

●        Regulatory Awareness