Serkan Kaplan
Verified Expert in Engineering
Software Engineer and Developer
Stuttgart, Baden-Württemberg, Germany
Toptal member since March 4, 2021
Serkan is a seasoned software engineer with 17 years of experience in consultancy and in-house development. For the last three years, he's been helping clients develop and improve their products all around the world. Previously, Serkan worked as a consultant for different companies and projects. As a software consultant, he led development teams of up to ten developers and worked on fintech, employee relations, learning management, and eCommerce applications.
Portfolio
Experience
- Java - 13 years
- Software Architecture - 12 years
- Spring Boot - 8 years
- Smart Contracts - 7 years
- Blockchain - 7 years
- Solidity - 6 years
- Kotlin - 4 years
- Corda - 4 years
Preferred Environment
MacOS, IntelliJ IDEA, Rust
The most amazing...
...thing I've achieved in seven years of my freelancing career is managing to sustain a 100% customer return rate.
Work Experience
Freelance Blockchain Developer
Toptal Client
- Developed a front-runner trading bot for a private investor with Solidity and Node.js.
- Handled different SSI projects and helped design a new product from the beginning.
- Constructed a payment gateway to integrate an existing payment platform with the Ethereum network.
Blockchain Developer
Harvey Nash
- Developed an SSI project from scratch, participating in all phases since its conception and architecture implementation with Hyperledger Indy and Aries to exchange master data and industrial certificates between two big German companies.
- Set up an agile mindset while working with conservative customers.
- Implemented a price and order negotiation system on Corda for low-trust and volatile price businesses.
DLT Software Developer
The Debtvision
- Contributed to a successful startup in its founding era.
- Designed and developed a decentralized system to manage multi-million euro loans and documents related to the loan.
- Oversaw external development and consulted the team on security issues.
Software Engineer
Harvey Nash
- Developed a loan transaction platform between Daimler AG and LBBW on the Proof of Authority (PoA) Ethereum network.
- Developed an environmental reward coin for Mercedes-Benz cars and a mobile application with a gamification aspect.
- Contributed to establishing a new team, forming an outstanding team culture, and hiring new colleagues.
Co-founder | Software Developer
Bal Yazilim Limited
- Managed a team of six. The team was first formed with junior developers, but after some time and long training sessions, I was proud of the team and their capacity.
- Collaborated with a large number of different customers for over seven years, with a 100% return rate among customers.
- Led the core team on an online training platform for the biggest GSM operator in Turkey.
Experience
Debtvision DLT Schuldscheindarlehen Platform
Education
Bachelor of Science Degree in Computer Science and Engineering
Yıldız Technical University - Istanbul, Turkey
Certifications
Corda Certified Developer
R3
Professional Scrum Master 1
Scrum.org
Skills
Libraries/APIs
Web3.js, Node.js, REST APIs, Claude API, React, JasperReports
Tools
IntelliJ IDEA, Ganache, Helm, GitHub, Amazon Elastic Container Service (ECS), Claude, Claude Code, Hyperledger Indy, Terraform, Geth (go-ethereum), Etherscan, Apache Tomcat, Gradle, GitLab CI/CD, Git
Languages
Java, Kotlin, Solidity, JavaScript, SQL, TypeScript, Solidity Assembly, XML, Python, GraphQL, PHP, PHP 5, Rust
Frameworks
Truffle, Spring Boot, Spring Security, Spring MVC, NestJS, Next.js, Angular, Hardhat, AngularJS, JBoss Seam, Spring, Express.js
Paradigms
Agile, REST, DevOps, Microservices Architecture, Scrum, Microservices, Fuzz Testing, Back-end Architecture, Database Design, Model Context Protocol (MCP), Requirements Analysis
Platforms
MacOS, Corda, Kubernetes, Blockchain, Ethereum, Docker, R3 Corda, Avalanche, Chainlink, Jakarta EE (Java EE or J2EE), AWS Lambda, Apache Kafka, Linux, Hyperledger, Amazon Web Services (AWS), Azure, Google Cloud Platform (GCP), Android, Hyperledger Sawtooth, Rancher, Amazon EC2
Storage
PostgreSQL, MySQL, Spring Data JPA, Amazon DynamoDB, JSON, NoSQL, MongoDB, Oracle 12c, Oracle 11g, DB
Industry Expertise
Project Management, Binance Cryptocurrency Exchange
Other
Software Engineering, IT Project Management, Software Architecture, Smart Contracts, Ethereum Smart Contracts, Cryptocurrency, Self-sovereign Identity (SSI), Team Management, Team Leadership, DApps, Prototyping, System Architecture, Customer Success, ERC-20, Distributed Ledgers, Distributed Ledger Technology (DLT), Architecture, Back-end, Technical Leadership, Leadership, BNB Smart Chain, Auditing, Security, Tokenomics, Ethereum Virtual Machine (EVM), Cryptocurrency Wallets, CTO, Web3, Vendor Management, Tokenization, Blockchain & Cryptocurrency, APIs, Foundry, Security Audits, Protocol Design, SQL Server, Artificial Intelligence (AI), Performance Optimization, Amazon MSK, Distributed Systems, Multithreading, Large-scale Distributed Systems, API Backwards Compatibility, SSH, ECS, Serverless, Learning Management Systems (LMS), API Integration, Fintech, AWS Cloud Architecture, Authentication, Authorization, Back-end Development, Payment Processing, SaaS Architecture, Hyperledger Aries, Digital Signatures, Zero-knowledge Proofs, ERC-721, TypeORM, Decentralized Finance (DeFi), Full-stack, Polygon, Crypto, ÐApp, Trading, Solana, Decentralized Autonomous Organizations (DAO), Apps, Offline Data Synchronization, Quarkus, Decentralized Applications, Product Design, Startups, Ethers.js, Non-fungible Tokens (NFT), Bitcoin
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