Backend-Focused Full-Stack Engineer for Consumer Web3 Wallet Operations and Development
Tokyo-based Japanese blockchain and Web3 company focused on non-custodial wallets, stablecoin payments, NFT services, and enterprise blockchain solutions.
Funding history
Investors
Projects
About HashPort Inc.
HashPort Inc. develops and operates blockchain products and services for consumers, businesses, financial institutions, and public-sector organizations. Its current core offering is HashPort Wallet, a non-custodial digital-asset wallet inherited from the EXPO2025 Digital Wallet, alongside HashPort Wallet for Biz stablecoin payments, enterprise wallet and blockchain solutions, SBT loyalty services, RWA tokenization, and HashPort Market | αU, an NFT marketplace supporting JPYC and credit-card payments.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
You will operate and improve a consumer wallet, tracing issues across interfaces, APIs, databases, and blockchain networks. You will investigate alerts and user reports, quantify impact, execute reversible releases, adapt to infrastructure and integration changes, and develop backend-led features including chain support, swaps, staking, notifications, and fiat gateways.
Requirements
- Have experience planning and executing production releases, including procedures, advance rehearsals, and post-release verification
- Have experience determining incident causes from logs and code and quantitatively reporting affected users, records, and periods
- Have experience designing and implementing failure-path tests for external API failures, interrupted processing, and duplicate execution
- Have experience changing production databases or configuration reversibly through transactions, backups, or staged application
- Have approximately three or more years of professional backend development experience
- Be able to read existing React interfaces in TypeScript and implement small changes or defect fixes
- Have experience quickly understanding and modifying an existing codebase written by others
- Have foundational knowledge of EVM-compatible chain integrations, including transaction submission, receipt confirmation, and event retrieval
- Have experience using coding agents such as Claude Code to investigate and modify existing code and create tests
- Have experience independently validating and correcting AI-generated changes
Responsibilities
- Investigate monitoring alerts, user inquiries, app reviews, and social media reports
- Trace issues across interfaces, APIs, databases, and blockchain networks
- Determine root causes from logs and code
- Quantify affected users, records, and time periods
- Fix confirmed defects across backend services and smaller frontend changes
- Create release procedures
- Rehearse releases in staging
- Apply production changes through reversible procedures
- Perform post-release verification
- Adapt systems to RPC, node, smart contract, and external API changes
- Develop support for new blockchain networks
- Develop swap and staking integrations
- Develop notification infrastructure
- Develop on-ramp and off-ramp integrations
- Use coding agents to investigate code, implement fixes, and create tests
- Validate AI-generated changes and establish testing, push, and review safeguards
Benefits
- Remote work on Tuesdays and Thursdays
- Claude Code Team Premium seat, with an individually contracted Max plan when needed
- Free drinks in the office
- Recreation subsidy of JPY 8,000 once per quarter
- Company social events approximately twice per year
