Summary
Overview
Work History
Skills
Websites
Timeline
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Constantin Zemelman

Summary

Experienced Engineering Director and fintech leader with 20+ years of hands-on programming experience and a proven track record in building global payment solutions. Expert in payment processing systems with extensive experience in developing fiat payment channels across multiple currencies and countries. Strong technical background in DLT/Blockchain technology including Ethereum, Solidity, and Hedera Hashgraph. Selected as Hedera Hashgraph 2020 MVP. Take-charge professional delivering executive support and team leadership to business operations. Dependable and detail-oriented to manage multiple tasks and priorities. Broad experience includes office management, accounting, accounts receivable, invoicing, dispatching, database management, vendor negotiations and contract management. Recognized for exemplary customer service and team collaboration. Methodical director with several years of comprehensive experience overseeing daily operations of company or organization. Hardworking and versatile professional well-versed in executing business strategies, preparing and implementing business plans and overseeing financial performance. Thorough knowledge of market changes and trends paired with strong grasp of corporate finance and performance measures.

Overview

26
26
years of professional experience

Work History

Engineering Director, Payment Channels

OKX
San Jose
01.2022 - Current
  • Lead a global team responsible for creating and maintaining payment infrastructure that processes transactions across multiple currencies and countries.
  • Expanded team from 4 to 10 engineers while maintaining high performance standards
  • Architected and implemented a comprehensive payment channels integration layer for global fiat on-ramp and off-ramp solutions
  • Developed robust payment infrastructure supporting multiple currencies across numerous countries
  • Streamlined payment processing workflows resulting in improved transaction success rates

Staff Wallet Engineer

GEMINI
New York
01.2020 - 01.2022
  • Expanded wallet subsystems to incorporate new digital assets, increasing platform capabilities
  • Optimized signature workflow architecture, reducing on-chain transaction failures by 30%
  • Engineered new subsystem utilizing multi-signature MPC protocol for enhanced security
  • Led vulnerability validation for smart contracts using formal verification techniques
  • Managed Ethereum forks readiness, ensuring platform stability during network changes
  • Technologies: Scala, Play, Solidity, OpenEthereum, Hardhat, Ganache, Manticore, PostgreSQL, Slick

Blockchain/DLT Software Technical Lead

OPENCROWD
New York
12.2017 - 11.2020
  • Led US-based and offshore development teams in building Hedera Hashgraph Services
  • Spearheaded multi-team implementation of a highly scalable value transfer platform using Hedera Hashgraph
  • Successfully integrated EVM to enable Solidity smart contracts on Hedera Hashgraph network
  • Designed and implemented multiple proof-of-concept projects utilizing Hedera Hashgraph services
  • Represented Hedera Services technology team in client meetings and technical discussions
  • Technologies: Hedera Hashgraph, Ethereum, Java, Spring Boot, GRPC, REST API, MongoDB, Solidity, ethereumj, ethereum-harmony

Global Payments Software Engineer Project Lead

FINASTRA
New York
04.2013 - 10.2017
  • Developed multi-tenant SaaS version of GPP SP Payment platform with modules for FedWire, Fed Securities, SWIFT, and NACHA
  • Enhanced reporting through OBIEE integration, implementing Oracle BI Dashboard and Oracle BI Publisher
  • Created token-based OFAC compliance search module using Oracle and IBM eXtreme Scale in-memory caching
  • Rapidly prototyped student loans marketplace on Ethereum blockchain using Solidity and ethereumj
  • Technologies: Java EE, Spring, Oracle database, WebLogic, OBIEE, IBM MQ, MongoDB, Angular, Web Services (REST, SOAP), Junit, Maven, Jenkins, ethereumj, ethereum-harmony, Solidity

Software Engineer - Project Leader

FUNDTECH
Jersey City
12.2001 - 04.2013
  • Developed and supported PayPlus USA payment system for electronic processing of principal payment types
  • Created SQL-based OFAC compliance search module using Accuity watch list data
  • Integrated Vasco authentication devices into PayPLUS USA for enhanced security
  • Modernized legacy fax system by implementing RightFax server integration
  • Provided high-level support for multiple financial institutions
  • Technologies: Visual C++, Visual Basic, SQL Server, Java, SSIS, Crystal Reports

Senior Software Engineer

FUNDTECH
12.1998 - 12.2001
  • Designed and deployed Client/Server system for correspondent bank account management
  • Created automated reconciliation engine for transaction matching via customized rules
  • Supported sales team with technical presentations and RFP response development
  • Technologies: VB/VC++, XML, SQL Server, Crystal Reports, Oracle

Skills

  • Java
  • Scala
  • Solidity
  • C
  • Visual Basic
  • Ethereum
  • Hedera Hashgraph
  • Smart Contracts
  • EVM
  • FedWire
  • SWIFT
  • NACHA
  • Payment Processing
  • Wallets
  • Oracle
  • SQL Server
  • MongoDB
  • PostgreSQL
  • Spring
  • Play
  • Angular
  • OBIEE
  • WebLogic
  • IBM MQ
  • IBM eXtreme Scale
  • Jenkins
  • Maven
  • Git

Websites

Timeline

Engineering Director, Payment Channels

OKX
01.2022 - Current

Staff Wallet Engineer

GEMINI
01.2020 - 01.2022

Blockchain/DLT Software Technical Lead

OPENCROWD
12.2017 - 11.2020

Global Payments Software Engineer Project Lead

FINASTRA
04.2013 - 10.2017

Software Engineer - Project Leader

FUNDTECH
12.2001 - 04.2013

Senior Software Engineer

FUNDTECH
12.1998 - 12.2001
Constantin Zemelman