Quality Assurance Engineer (Mid - Senior)
About us:
B2C2 is a digital asset pioneer focusing on building future-proof ecosystems. The firm enables institutional access to crypto through reliable liquidity services regardless of market conditions. Its success stems from utilizing crypto-native technology, continuous product innovation, and serving as a trusted partner for various institutions globally. Established in 2015, and acquired by SBI, a Japanese financial group in 2020, B2C2 operates independently. Headquartered in the UK, with additional offices in the US and Japan, B2C2 OTC Ltd. holds authorization and regulation by the UK’s Financial Conduct Authority (FRN 810834).
We take pride in our company culture and knack for attracting top talent aligned with our values. If you seek a role in a dynamic company within a burgeoning industry, continue reading.
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B2C2 stands out as a leading cryptocurrency trading firm, acting as a principal risk market maker to both exchanges and OTC clients. The mission is to enhance transparency and operational efficiencies within this evolving asset class.
By bridging traditional financial and cryptocurrency markets, B2C2 is the trusted liquidity provider for brokerages, exchanges, banks, and fund managers, with a globally dispersed team possessing extensive expertise in conventional financial and crypto markets.
Emphasizing company culture and the ability to bring in not only top-tier talent but the right individuals, we welcome those looking to be part of an exciting industry at a vibrant company.
Overview of Team:
The Quality Assurance team is dedicated to offering engineer-focused testing services with a skilled, small team covering all front and middle office systems and process testing utilizing automation for efficient testing and enhanced quality.
Collaborating across technology, trading, and various business units, we develop tools and processes essential for B2C2 to sustain innovation swiftly and create industry-leading systems for both clients and internal use.
Scope of Role:
As a quality assurance engineer, your duties will involve contributing to constructing strategic functional and non-functional test frameworks and tools while prioritizing release and project testing requirements.
Additionally, as part of multiple agile teams and the QA horizontal, close collaboration with developers and business stakeholders is essential. This role will work towards satisfying internal quality assurance objectives as well as meeting the visibility testing needs of both internal and external stakeholders such as the risk team and regulators.
Key Responsibilities:
- Maintain and review regression test packs
- Contribute to developing tooling and test frameworks for functional and non-functional testing
- Take ownership of testing and quality assurance for one or more project teams concurrently
- Deliver system and system integration testing for releases
- Support user acceptance testing (UAT) for high-risk projects
- Create automated tests to evaluate new and existing systems and developments
- Present testing reports to project stakeholders to facilitate testing sign-off and project conclusion
- Aid the support and development teams in diagnosing and investigating production issues and testing subsequent fixes
- Assist the head of QA in organizing and managing business-focused manual test cases and maintaining automated test cases
The list above does not include all responsibilities, and tasks can change based on evolving roles within the company and broader business objectives of B2C2.
Mandatory Skills:
- Designing test automation frameworks for intricate systems
- Java proficiency and developing Java-based test automation frameworks
- Establishing and utilizing tooling for non-functional testing
- Analyzing tests and creating test cases with a risk-focused approach
- Investigating complex issues across a system stack
Preferred Skills:
- Conducting test automation using Cucumber to define test cases, including UI automation
- Proficiency in Python and Rust, adaptable to learning and working with other languages
- Applying test analysis to high-frequency trading systems with focus on functionality and non-functionality
- Proficiency in KDB, Q, AWS, and Kubernetes
- Understanding of trading and middleware protocols and technologies, such as Redis, FIX protocol, REST APIs, and Websockets
- Keen interest in trading systems and cryptocurrency
At B2C2, a strong culture underpins our success. We are an ambitious, innovative, meritocratic, collegiate, and risk-aware organization, striving for excellence in all aspects.
Equal Employment Opportunities Policy:
B2C2 upholds a commitment to equal employment opportunities for applicants and employees across various backgrounds. Discrimination based on race, color, religion, gender, national origin, age, disability, genetic information, marital status, or any other protected category is strictly prohibited. The company fosters an inclusive environment to attract, engage, promote, and retain the best talent by offering flexible working arrangements for its employees.
Chief Technology Officer (CTO) / Senior Full-Stack Developer (Web3)
We are building a next-generation Web3 social platform designed to redefine how digital communities connect, collaborate, and grow.
Backed by years of experience within the cryptocurrency, blockchain, and digital asset ecosystem, our team has developed deep insights into how founders, developers, investors, creators, and communities interact. This understanding inspired us to create a platform that goes beyond financial applications and focuses on empowering meaningful social engagement.
Our mission is to build a transparent, community-driven social network where users can share ideas, collaborate on projects, discover opportunities, and create lasting relationships. We believe the next evolution of social media will be powered by decentralized technologies while maintaining an exceptional user experience, simplicity, and long-term sustainability.
We are seeking an experienced Chief Technology Officer (CTO) or Senior Full-Stack Developer who is passionate about Web3 and capable of leading the technical vision, architecture, and execution of our platform from the ground up.
Responsibilities
Lead the technical strategy and product architecture.
Design and build scalable backend systems and modern frontend applications.
Develop high-performance APIs and real-time features.
Integrate blockchain technologies, wallets, and Web3 authentication where appropriate.
Build secure, reliable, and maintainable infrastructure.
Collaborate closely with product, design, and leadership teams.
Establish engineering best practices, code quality standards, and development workflows.
Mentor engineers and help grow the technical organization.
Evaluate emerging technologies and implement solutions that improve scalability, security, and user experience.
Requirements
5+ years of professional software development experience.
Strong experience with modern JavaScript/TypeScript ecosystems.
Experience with React, Next.js, Node.js, or similar technologies.
Solid understanding of system architecture, cloud infrastructure, databases, and API design.
Experience building scalable consumer-facing products.
Familiarity with blockchain technologies, Web3 infrastructure, wallets, smart contracts, or decentralized applications.
Strong knowledge of security best practices and application performance optimization.
Excellent problem-solving and communication skills.
Ability to work independently in a fast-paced startup environment.
Preferred Qualifications
Experience building Web3 or crypto products.
Understanding of decentralized identity, token ecosystems, or on-chain social applications.
Experience leading engineering teams or serving in a technical leadership role.
Background in DevOps, CI/CD, Docker, Kubernetes, or cloud platforms such as AWS or GCP.
Experience with real-time messaging, social platforms, or community products.
What We Offer
Competitive full-time compensation.
Opportunity to build a product from an early stage with significant technical ownership.
Flexible and remote-friendly work environment.
Collaborative team focused on innovation and long-term impact.
Work on cutting-edge Web3 technologies and help shape the future of digital communities.
Opportunity for career growth and leadership as the platform scales.
If you are excited about building the next generation of Web3 social experiences and want to make a meaningful impact from the earliest stages, we'd love to hear from you.
ZK-Infrastructure Engineer
Expectations:
Design and implement circuits for merkle membership and signature aggregation
Optimize witness generation and prover memory usage
Build a distributed prover system with load balancing
Reduce proving time from 30s to <5s using GPU acceleration
Collaborate with researchers on new polynomial commitment schemes
Write performance benchmarks and regression tests
Deploy provers as microservices on Kubernetes
Maintain a devnet for testing with real transaction data
Contribute to open-source ZK libraries (e.g., gnark, arkworks)
Nice to have:
Experience with MPC (multi-party computation)
Knowledge of TLSNotary or ZKEmail
Published papers or talks at ZK conferences
Chinese+English language proficiency
Smart Contract Engineer (Solidity / Rust)
Expectations:
Design and deploy upgradeable proxy contracts (UUPS)
Write high-assurance tests with invariant testing (Foundry)
Implement access control (Ownable2Step, roles)
Integrate with Chainlink Automation and CCIP
Write Natspec docs and deployment scripts
Participate in internal security reviews and bug bounties
Optimize storage layouts to reduce gas costs by >15%
Collaborate with the research team on novel staking mechanisms
Nice to have:
Experience with LayerZero or Hyperlane
Published audit reports or contest wins (Code4rena / Sherlock)
Knowledge of ZK-proofs (basic)
Chinese language proficiency
Director of BD & Strategic Partnerships
You will work closely with the founding team to develop and execute global BD and fundraising strategies, expand and maintain relationships with projects, exchanges, funds, family offices, high-net-worth individuals, and other key ecosystem participants, and continuously drive business partnerships, capital introduction, and long-term strategic value creation. This role is ideal for someone with strong execution, mature business judgment, and a solid understanding of capital markets, who can thrive in a fast-paced, high-autonomy, crypto-native environment.
Responsibilities
Develop and execute business development, strategic partnership, and fundraising plans across Klein Labs’ business lines, driving revenue growth, partnership conversion, and capital introduction.
Build and maintain long-term relationships with exchanges, projects, DAOs, market makers, funds, family offices, HNWIs, and other key ecosystem participants.
Design and implement partnership models across market-making, OTC, treasury, ventures, and fund-related business lines to improve conversion efficiency and long-term value creation.
Support institutional fundraising and LP relationship management, including investor outreach, investor communication, due diligence coordination, subscription processes, and capital onboarding.
Clearly communicate Klein Labs’ business model, fund strategy, return profile, risk framework, and differentiated strengths to external partners and investors, building trust and improving conversion.
Manage and continuously optimize external materials, including company introductions, business decks, fundraising decks, one-pagers, FAQs, DDQs, and investor update materials, ensuring professionalism and consistency in external messaging.
Represent Klein Labs in key business negotiations, industry events, important external meetings, and strategic partnership discussions.
Work cross-functionally with management, research, trading, legal, and operations teams to drive partnership execution, fundraising progress, and long-term relationship management.
Support the expansion and management of the global BD team as the business grows, including KPI setting and performance culture development.
Requirements
3+ years of experience in business development, strategic partnerships, institutional fundraising, investor relations, sales, or related functions, with prior crypto industry experience preferred.
A clear and verifiable track record in driving business growth, partnership conversion, or fundraising outcomes, with the ability to independently move initiatives forward.
Strong understanding of the Web3 ecosystem, crypto market structure, token economics, and strategic partnership dynamics.
Familiarity with how to engage and build trust with projects, exchanges, funds, family offices, HNWIs, institutional investors, and crypto-native LPs.
Strong communication, relationship-building, material preparation, and process management skills, with the ability to coordinate across multiple stakeholders in complex situations.
Highly execution-oriented, results-driven, and capable of building systems and processes in a fast-paced, high-ownership environment.
Professional working proficiency in English.
Candidates based in Singapore or Dubai are strongly preferred.
Existing relationships with institutions, family offices, HNWIs, crypto-native LPs, exchanges, or project teams are a strong plus. Experience in liquidity management, trading services, funds, asset management, primary markets, or related market structure is also preferred.
What We Offer
A key role with direct exposure to Klein Labs’ core business growth, strategic partnerships, and capital network development.
Close collaboration with the founding team and senior leadership, with direct involvement in shaping business direction, fundraising strategy, and external positioning.
Competitive compensation, performance-based incentives, and long-term upside.
Direct access to high-quality deal flow, institutional relationships, and primary market opportunities.
Deep involvement across CEX, DEX, and both on-chain and off-chain collaboration ecosystems.
A highly flexible, low-hierarchy, and deeply crypto-native working environment.
Senior blockchain and frontend developer
There are 7 developers in our team right now.
We just started Front-UI development but our current progress is getting slowly so we are looking for developers who has experience in Blockchain development.
For this project, you need to have proven experience in React, TypeScript, Node.js and Web3.js for Front-end Development or Solidity for Smart Contracts Development.
If you are interested, then we can discuss more details.
Thanks Regards.