David Bong C. C., Developer in Tokyo, Japan
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David Bong C. C.

Verified Expert  in Engineering

Blockchain Developer

Tokyo, Japan
Toptal Member Since
September 7, 2022

David is a senior full-stack blockchain engineer with 20 years of experience in software engineering. He has demonstrated vast knowledge and technical skills across various industries such as oil and gas, telecommunications, banking, and enterprise solutions, including developing a large-scale enterprise solution for the global company Royal Dutch Shell. David picked up the latest blockchain technology and skills and is a Certified Blockchain Solution Architect.


Amazon Web Services (AWS), Go, Rust, Solidity, Hedera Hashgraph, Polygon...
Blockchain, Go, JavaScript, Hardhat, Microservices Architecture, Azure...
Deloitte Japan
Azure, Solidity, Ethereum, Consensus Mechanism, Cryptography, Microservices...




Preferred Environment

Windows 10, MacOS, Visual Studio Code (VS Code), Slack, Remix IDE, Rust

The most amazing...

...thing I've done was develop a microinsurance POC solution using the Quorum private blockchain and Solidity smart contracts

Work Experience

CTO | Senior Blockchain Solution Architect

2022 - 2023
  • Delivered several projects successfully, including white-label NFT marketplaces, ESG blockchain solutions, and property tokenization platforms, using leading blockchain protocols such as Hedera, Polygon, and Hyperledger Fabric.
  • Utilized Jira, Lucidchart, Microsoft PowerPoint, Microsoft Project plan, and Notion.
  • Implemented a while-label marketplace with a high volume of transactions.
Technologies: Amazon Web Services (AWS), Go, Rust, Solidity, Hedera Hashgraph, Polygon, Ethereum, Central Bank Digital Currency (CBDC), Azure Kubernetes Service (AKS), Hashgraph

Blockchain Solution Architect and Technical Lead

2020 - 2021
  • Designed and developed various proof of MVP projects using different blockchain protocols, namely Ethereum, Polygon, Hyperledger Fabric, Hedera, and IPFS.
  • Managed and tracked projects and source code using the Visual Studio online portal and Jira.
  • Engaged in user acceptance testing and go-live activities and followed up with customers to build production versions.
Technologies: Blockchain, Go, JavaScript, Hardhat, Microservices Architecture, Azure, Amazon Web Services (AWS), Amazon Quantum Ledger Database (QLDB), Azure Functions, Azure Active Directory, Solidity, Python 3, PostgreSQL, MongoDB, TypeScript

Blockchain Research and Development Lead

2019 - 2020
Deloitte Japan
  • Developed a microinsurance POC solution using the Quorum private blockchain and Solidity smart contracts.
  • Tracked and fixed bugs using the Deloitte tracking system and GitHub.
  • Supervised the POC implementation and demo sessions with the client.
Technologies: Azure, Solidity, Ethereum, Consensus Mechanism, Cryptography, Microservices, Python 2, Node.js, React, Apache Kafka

NFT Marketplace and Metaverse

A project promoting a new building launching in the city. I was the core solution architect and technical lead to design, build, and implement the project until go-live.

The project was to build a metaverse and a non-fungible tokens (NFT) marketplace, promoting the new building in conjunction with blockchain and digital assets. The platform features included a custodial and non-custodial wallet mechanism, secondary marketplace, product redemption, and payment gateway integration.

Health Passport for PwC Japan

A solution built in response to COVID-19 two years ago that allows users to show proof of the PCR test result, permitting them to enter buildings or restaurants. The main architecture design includes an off-chain transaction to store sensitive information and an on-chain transaction to record hash values for verification purposes.

Non-custodial Crypto Wallet Platform

A platform built for the crypto natives to self-custody their digital assets and cryptocurrencies. Its functions include NFT features, a crypto news feed, crypto buy and sell, and crypto send and receive. The features are across multiple major blockchain protocols, notably Bitcoin, Bitcoin Cash, Ethereum, and other ERC-20 tokens.

SmartRent Decentralized Online Property Marketplace

A decentralized platform allowing owners and tenants to sign a tenancy contract online, leveraging the Ricardian contract. The deposits and tenancy agreements or contracts are stored on the public blockchain.

Decentralized Document Control System

A document control system built on top of the well-known public distributed ledger technology protocol called Hedera Hashgraph blockchain to provide high-performance and throughput of transactions with decentralized, consensus, immutability, and integrity.

Certified Ethereum Developer

ConsenSys Academy


Blockchain Security Architect

Blockchain Training Alliance


Blockchain Architect

Blockchain Training Alliance


Certified Blockchain Solution Architect (CBSA)

Blockchain Training Alliance


Node.js, Web3.js, React


Remix IDE, Mocha, Azure Kubernetes Service (AKS), Slack, Azure Active Directory B2C (ADB2C)


Blockchain, Azure, Ethereum, Amazon Web Services (AWS), Azure Functions, Docker, Kubernetes, MacOS, Visual Studio Code (VS Code), Apache Kafka, Hedera Hashgraph


Hardhat, Truffle, Angular, NestJS


JavaScript, C#, Solidity, Python 3, TypeScript, Rust, Go, Java 8, Python 2


Azure Active Directory, PostgreSQL, MongoDB


Microservices Architecture, Microservices


Consensus Mechanism, Cryptography, IPFS, Windows 10, Amazon Quantum Ledger Database (QLDB), Apache Cassandra, Security, Polygon, Central Bank Digital Currency (CBDC), Hashgraph

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