SORAMITSU is the developer of and major contributor to the open-source blockchain platform Hyperledger Iroha, which is tailored for enterprise and public-sector use. Hyperledger Iroha, a project of Hyperledger Foundation, part of the Linux Foundation, has a permissions system that is scalable and performant.

Utilizing blockchain, SORAMITSU has developed a digital currency for the National Bank of Cambodia, a CBDC Proof-of-Concept with the Bank of the Lao PDR, a closed-loop payment system for the University of Aizu in Japan, an identity verification system prototype for Bank Central Asia in Indonesia, we were finalists in the Monetary Authority of Singapore CBDC Challenge, and are currently participating in Asia-Pacific's first proof-of-concept test of a cross-border, multi-currency security settlement system using distributed ledger technology with the Asian Development Bank. We have also conducted proof-of-concept tests for several major Japanese enterprises, and are active contributors to open source projects, such as Klaytn, South Korea's leading Layer-1 blockchain, KAGOME, the C++ Polkadot Host implementation, the SORA crypto-economic system, the Polkaswap DEX, and the DeFi wallet, Fearless Wallet

Based on these experiences, SORAMITSU aims to deploy cutting-edge technology on a global level in order to expedite financial inclusion and health, mitigate economic inefficiencies, and contribute to the fulfilment of the Sustainable Development Goals.

You can find out more by visiting our homepage at soramitsu.co.jp or check out our Twitter profile.

We are seeking a highly skilled blockchain developer with deep expertise in blockchain technologies and smart contract development, focusing on Solidity, Ethereum, and various Layer 1 and Layer 2 protocols. This role will involve designing, implementing, and optimizing secure and scalable blockchain solutions.

You will be responsible for:

• Develop, deploy, and maintain secure, efficient, and scalable smart contracts on Ethereum and other blockchain networks.
• Architect decentralized systems and define smart contract standards for new projects and features.
• Lead code reviews and provide mentorship to junior and mid-level developers.Optimize smart contract code for gas efficiency, performance, and security.
• Collaborate with cross-functional teams including frontend developers, product managers, and security experts.Identify and mitigate security risks within smart contracts.
• Stay up-to-date with the latest trends, tools, and best practices in Solidity and blockchain development.
• Perform rigorous testing and auditing of contracts, and ensure all code is secure and bug-free.

Requirements:

• 3+ years working specifically with Solidity and Ethereum-based development.
• Deep understanding of Ethereum's architecture, smart contracts, and related technologies.
• Proficient in Solidity, Web3.js, and Ethers.js.Experience with deploying and interacting with smart contracts on Ethereum, Binance Smart Chain, or other EVM-compatible blockchains.
• Familiarity with common design patterns (e.g., ERC-20, ERC-721, ERC-1155) and decentralized protocols.Expertise in smart contract security practices, including common vulnerabilities (e.g., reentrancy, overflow/underflow, front-running).
• Knowledge of decentralized finance (DeFi) protocols and their smart contract ecosystems.
• Experience with testing frameworks (e.g., Truffle, Hardhat, Foundry).
• Experience with CI/CD pipelines and blockchain-specific deployment strategies.
• Ability to communicate complex technical concepts effectively to both technical and non-technical stakeholders.
• Strong problem-solving, debugging, and optimization skills.
  Preferred:
• Experience in developing for Layer 2 networks or alternative blockchain protocols (e.g., Optimism, Arbitrum, Polygon).
• Familiarity with cross-chain technologies and bridging protocols.
• Experience with smart contract auditing tools like Slither, MythX, and others
• Experience with Polkadot ecosystem (Rust, Substrate)

General Skills:

• Programming Languages: Solidity, JavaScript, Python, with knowledge of Rust considered a plus.
• Blockchain Platforms: Ethereum, Binance Smart Chain, Polygon, Arbitrum, Optimism, etc.
• Frameworks & Libraries: Truffle, Hardhat, Foundry, Web3.js, Ethers.js.
• Security Best Practices: Smart contract auditing, vulnerability mitigation, best practices for gas optimization.
• Collaboration Tools: Git, GitHub/GitLab, JIRA, Slack, etc.
• Soft Skills: Strong communication in English, problem-solving, and analytical thinking.

Additional Requirements:

• Please include a link to your GitHub profile showcasing examples of your code or repositories where you’ve contributed.

What we offer:

• A relaxed remote-first (work from anywhere) work environment with flexible working hours
• A permanent, full-time role with a rapidly growing international team of professionals
• An educational budget to support your continued growth and development
• Opportunities to attend global meetups and conferences for learning and/or speaking engagements
• An opportunity to be a part of an award-winning team designing a better world through decentralized technologies

This is a remote position. Our distributed team is mostly spread across Europe and Asia. Team meetings are held generally during European working hours, and it is expected that you would adapt if necessary and be available accordingly.

If you have the required qualifications and are passionate about the Web3 industry, we encourage you to apply for this exciting opportunity.

SORAMITSU values diversity and is committed to providing equal opportunities for all applicants and employees. Our employment decisions, such as hiring, promotion, discipline, and termination, are based solely on an individual's qualifications, performance, and business needs. We do not discriminate against anyone on the basis of their race, color, religion, marital status, age, national origin, ancestry, physical or mental disability, medical condition, pregnancy, genetic information, gender, sexual orientation, gender identity or expression, veteran status, or any other protected status under federal, state, or local law.

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Pond is pioneering blockchain’s foundational models by leveraging graph deep learning to predict on-chain behaviors and accelerate the development of AI-powered, crypto-native applications. Its solutions target key sectors including DeFi, social networks, trading, MEV, and security, utilizing an innovative, decentralized AI development process.

The technical team brings extensive expertise from leading graph AI companies such as WeChat, TigerGraph, and Yuga Labs. With a remarkable track record of over 40 publications in prestigious journals and conferences—such as IEEE, Nature, Harvard Business Review, ICML, NeurIPS, CVPR, and PNAS—the team is at the forefront of cutting-edge AI research and application.

Our $7.5M seed round is led by Archetype, with participation from Cyber Fund (Lido founder’s fund, which rarely invests directly, backed Solana pre-seed and Ethereum pre-ICO), Coinbase Ventures, Delphi Digital and Anagram (the fund of Solana’s president and former president of Polychain).

We have a 30+ wide range of angels in DeFi, MEV, social, security, and more including the co-founder of Near, the co-founder of ENS, CTO of Exo Labs, co-founders of Plume Network, COO of Matrixport, the Head of Market Research of Flashbots, the founder of Mamori, the founder of SEDA, former GP of Variant—Spencer Noon, the founder of Zerion, the founder of Nuffle, the founder of OpenGradient, and others.

For more:

• Website
• Twitter

The role:

We are seeking a skilled and passionate Smart Contract Engineer to join our innovative blockchain team. The ideal candidate will have proven experience in developing and deploying smart contracts and be deeply familiar with blockchain technologies. As a Blockchain Smart Contract Engineer, your main task is to develop, test, and maintain smart contracts on different blockchains according to business needs.

Key Responsibilities:

• Design, develop, test, and deploy smart contracts on blockchain platforms such as Ethereum, Base, or Solana.
• Collaborate with the development team to create and implement decentralized applications (DApps).
• Write high-quality, secure, and sustainable code for blockchain applications.
• Perform code reviews and provide constructive feedback to peers.
• Maintain and optimize existing blockchain applications and smart contracts.
• Work closely with project managers and other stakeholders to define and achieve project goals.
• Stay updated with the latest blockchain technologies and cryptographic methods.
• Contribute to the architecture and design decisions for blockchain systems.

Required Skills and Qualifications:

• Bachelor’s degree in Computer Science, Engineering, or a related field.
• 2+ years of experience in blockchain development.
• Strong proficiency in Solidity and other smart contract languages.
• Experience with blockchain development frameworks and tools (e.g., Truffle, Hardhat, Remix).
• Understanding of consensus algorithms and blockchain protocols.
• Knowledge of front-end technologies (e.g., HTML, CSS, JavaScript) for DApp integration.
• Experience with version control systems, preferably Git.
• Excellent problem-solving skills and ability to work under pressure.

Preferred Skills:

• Familiar with Solidity language, and preferably have some understanding of Rust.
• Familiarity with off-chain storage solutions and integrations (IPFS, The Graph).
• Understanding of Layer 2 scaling solutions (e.g., Optimism, Arbitrum).
• Contributions to open-source blockchain projects.
• Prior experience in a fintech environment.

About The Role:

The Engineering team at Shardeum is responsible for delivering the Shardeum Mainnet and developing critical components such as the smart contract platform, consensus layer, and protocol layer. As part of this team, the SDET (Software Development Engineer in Test) will play a key role in ensuring the quality, reliability, and performance of Shardeum’s decentralized platform through robust test automation, debugging, and validation processes.

This role is ideal for engineers who have a passion for test automation, load testing, and identifying root causes of bugs to enhance blockchain performance and scalability. If you’re excited about solving unique challenges in the Web3 space and driving innovation in blockchain testing methodologies, we want to hear from you!

What You'll Be Doing:

• Analyze bug tickets, debug code, and identify the root cause of errors across the Shardeum platform.
• Design, develop, and maintain test automation frameworks and reusable test scripts to validate core functionality, including nodes, consensus mechanisms, smart contracts, and blockchain transactions.
• Develop and execute load testing scripts to validate system performance under high transaction loads and varying node configurations.
• Create comprehensive test coverage through functional, integration, system, and regression testing while optimizing test suites and identifying performance bottlenecks.
• Develop end-to-end (E2E) test cases for complex workflows, ensuring reliability of consensus protocols and smart contract execution.
• Collaborate closely with development teams to integrate testing into CI/CD pipelines, improve testing workflows, and troubleshoot dependency failures.
• Build and maintain internal tools to improve developer experience, productivity, and test efficiency.
• Troubleshoot highly complex automated testing failures using industry-standard frameworks and custom tools, working with developers and backend partners to triage issues and improve E2E reliability.
• Develop monitoring tools and utilities to track blockchain-specific performance metrics and test results.
• Participate actively in agile ceremonies, including sprint planning, stand-ups, and retrospectives, to drive testing best practices.
• Continuously research and adopt innovative tools, frameworks, and testing methodologies to improve quality, scalability, and efficiency of testing processes.

What We're Looking For:

• 5+ years of experience in Software Engineering or SDET roles with a focus on automated testing.
• Strong expertise in designing and maintaining test automation frameworks (e.g., Jest, Playwright) and load testing tools (e.g., k6, JMeter).
• Proficiency in programming languages like TypeScript/JavaScript or Node.js, with the ability to develop robust and reusable test scripts.
• Proven ability to analyze and debug complex codebases, troubleshoot multi-tier web architecture issues, and identify root causes of failures.
• Experience integrating automated tests into CI/CD workflows (e.g., GitHub Actions, Jenkins).
• Expertise in defining and implementing release, regression, and smoke testing strategies for large, multi-team applications.
• Experience with white-box testing methodologies to ensure deep validation of internal components.
• Strong problem-solving and critical-thinking skills, particularly in analyzing blockchain-specific issues.
• You have a tester mindset, are curious, and excel at designing innovative and interesting test scenarios.
• You are creative in applying proven tools/test frameworks as well as crafting new solutions to challenging problems.
• Knowledge of Agile/Scrum methodologies and the software development lifecycle.
• Excellent verbal and written communication skills for clear bug reporting and collaboration across teams.

We'd Love If You Have:

• Experience with testing decentralized applications (dApps), consensus protocols, or blockchain platforms.
• Experience in running nodes within blockchain networks and monitoring performance metrics.
• Familiarity with blockchain tools and frameworks (e.g., Web3.js, Hardhat, Truffle).
• Contributions to open-source projects related to testing, automation, or blockchain.
• A passion for emerging technologies, including Web3, AI, and distributed systems.
• Experience using or contributing to the Shardeum open-source repos.
• Familiarity with blockchain performance benchmarks and profiling tools.
• Knowledge of the Bitcoin and Ethereum whitepapers.

Apply Now: