Senior Java Developer

Zielona Góra, Poland
Full time
Office
Compensation is not specified
Role
Backend Engineer
Description

About us:

B2C2 is a leading player in the digital asset space, spearheading the development of the future ecosystem. The firm has facilitated institutional access to cryptocurrency by ensuring reliable liquidity in various market conditions.

Built on cutting-edge crypto-native technology and a culture of continuous innovation, B2C2 has become the preferred partner for diverse institutions worldwide. Established in 2015 and acquired by the Japanese financial group SBI in 2020, B2C2 operates independently. We are headquartered in the UK, with additional offices in the US and Japan. B2C2 OTC Ltd. is authorized and regulated by the UK’s Financial Conduct Authority (FRN 810834).

At B2C2, we take pride in our exceptional company culture and our ability to attract not just top talent, but the right individuals for our team. If you're seeking a challenging role in a thriving industry at a dynamic company, please continue reading.

SCOPE OF THE ROLE

This is an exciting opportunity for successful candidates to join one of our Java development teams.

Role and Responsibilities

  • Develop and maintain Java-based applications and components efficiently, ensuring high-quality code and adherence to coding standards.
  • Enhance in-house shared libraries, ensuring their reliability and efficacy.
  • Write robust, well-documented, and thoroughly-tested code to meet project objectives and deadlines.
  • Troubleshoot software defects and technical issues to minimize disruption in revenue-generating processes.
  • Collaborate with cross-functional teams to define and implement new features.
  • Engage in code reviews and incorporate feedback.
  • Maintain and enforce comprehensive internal documentation.

Skills Required

  • 8+ years of Java software development experience.
  • Profound understanding of object-oriented programming concepts and advanced design patterns.
  • Proficient in writing clean and efficient code.
  • Experienced in writing automated tests and expanding test coverage.
  • Demonstrated ability to take ownership of projects from inception to delivery.

Opportunity:

  • Rapid career growth opportunities with a focus on pushing individuals to perform at their best.
  • Exposure to the latest technologies and products to enhance productivity.
  • Excellent career advancement possibilities within a growing company.
  • Involvement in shaping the future of financial technology with a meaningful impact on B2C2's future.
  • Engaging work environment balancing hard work with fun.
  • Bi-annual performance reviews and discretionary bonuses.
  • Ability to create a difference and contribute meaningfully.
  • Forward-thinking and dynamic organizational culture.

Desired Skills:

  • Experience with asynchronous event-driven network applications based on Netty.
  • Proficiency in low GC techniques in Java.
  • Knowledge of relational databases, SQL, web technologies, and protocols.
  • Exposure to technologies such as PostgreSQL, Kafka, Redis, gRPC, Linux, Docker, Kubernetes, AWS, and Python.
  • Interest in cryptocurrency and trading.

A strong culture underscores the success of leading companies, and at B2C2, we pride ourselves on being values-driven.

  • Ambition: Striving for historic achievements through excellence.
  • Innovation: Forward-thinking in solutions for clients and employees.
  • Meritocracy: Recognizing positive contributions organization-wide.
  • Teamwork: Achieving goals through collaboration and a positive environment.
  • Risk Awareness: Making informed decisions and practicing thoughtful risk management.

Equal Employment Opportunities Policy:

B2C2 upholds a policy of equal employment opportunity for all applicants and employees, regardless of background. Discrimination based on race, color, religion, sex, national origin, age, disability, genetic information, marital status, or other protected factors is not tolerated. We are committed to an inclusive environment that attracts, engages, promotes, and retains top talent and will consider flexible working arrangements for all roles.

Skills Required
Avatar
B2C2
Company size
Not specified
Location
United States
Description
Not specified

More Full-time Jobs

Show more

Startup

Chamoli Gopeshwar, India
Chamoli Gopeshwar, India
Part time
Office
Thank you for giving me the job. If I get a job in the future, I will get a chance to gain experience of working in the world. Thank you.
Payment in Crypto

Senior Software Engineer (Blockchain)

Mumbai, India +3
Mumbai, India +3
Full time
Remote
About MentTech
MentTech is a forward-thinking technology company dedicated to transforming how mentoring and learning are delivered in the digital age. By combining advanced tools, intelligent systems, and a human-first approach, MentTech helps individuals, teams, and organizations harness the power of mentorship to unlock potential, build skills, and achieve lasting growth.
The Role
We are seeking a Smart Contract Developer responsible for ensuring that game listings within MentTech work properly and ensuring compliance with all game store policies.
Key Responsibilities:
 • Architect, implement, and deploy secure smart contracts for an on-chain Play-to-Earn GameFi ecosystem
 • Lead contract design decisions with a focus on robustness, auditability, gas efficiency, and resilience to attack vectors
 • Mentor/junior developers: perform code reviews, establish standards, best practices in security & testing
 • Collaborate cross-functionally with game designers, backend, QA, and security teams to align smart contract features with product roadmap
 
Qualifications:
 • 2+ years hands‐on experience developing & deploying smart contracts (Solidity / EVM or equivalent) in production environments
 • Track record of writing secure contracts, familiarity with common vulnerabilities (reentrancy, integer over/underflow, front-running, flash loans, etc.)
 • Experience with audits, formal verification, fuzz testing, or other advanced contract assurance methods
 • Strong test suite / CI workflow skills; comfortable using tools like Hardhat, Foundry, Truffle etc.
 • Solid understanding of GameFi mechanics and how on-chain economics work
 
Bonus Points:
 • Experience on multiple EVM chains or Layer-2 / sidechains
 • Knowledge of cross-chain bridges, oracles, NFTs, tokenomics design
 • Contributions to open-source security tooling or prior audit reports or published code you’re proud of
 
Why join MentTech?
At MentTech, we cultivate a culture of flexibility, autonomy, and the freedom to make a real impact on the broader Web3 ecosystem. Experience the advantages of a fully remote working environment where your expertise and contributions are rewarded with competitive compensation tailored to your role and project influence.
Ment Tech Labs
 • Employee Equity & Incentives: Unlock future growth with equity and other potential incentives.
 • Entrepreneurial Culture: Join a collaborative environment where we innovate together as partners.
 • Cutting-edge Innovation: Work at the forefront of gaming and blockchain.
 • Key Strategic Projects: Be part of transformative initiatives that are redefining the gaming landscape.
 • Remote Flexibility: Enjoy a truly flexible, fully remote work setup that supports your lifestyle.
 • Talented Team: Collaborate with a team of passionate, driven, and skilled professionals.
 • Community Impact: Contribute to the growth and success of the Web3 and gaming communities.
 • Flexible Payment Options: Receive payments in crypto or fiat, tailored to your preference.
 • Growth Opportunities: Access valuable learning experiences and development paths.
 
MentTech Labs, Inc. is an equal opportunities workplace that doesn’t discriminate based on race, ethnicity, gender, ancestry, national origin, religion, sex, sexual orientation, gender identity, age disability, veteran status, genetic information, marital status, or any other legally protected status.
Payment in Crypto
4,000-6,000
Monthly
See details

Senior web3 engineer

Treynor, USA
Treynor, USA
Part time
Remote
About the Project:
We’re building a SocialFi platform combining real estate and DeFi. After launching our MVP, we’re now progressing to version 2.
 
Role:
Join our remote team to develop website, smart contracts, integrate blockchain features, and ensure platform security.
 
Responsibilities:
- Develop and deploy smart contracts on Ethereum or Layer 2.
- Integrate wallet connect and decentralized features.
- Collaborate and direct contribute with frontend/backend teams.
- Conduct security audits.
 
Requirements:
- Experience with React, Ethers.js, Web3.js.
- Familiarity with wallet extensions and DeFi protocols.
- Ability to fix errors within 1 hour during tests.
- Comfortable working independently in a remote setup.
 
Nice to Have:
- Knowledge of cross-chain protocols or cryptography.
- Experience in social finance or real estate blockchain projects.
 
Application:
Send your resume and Linkedin profile. Selected candidates will do a quick coding test.
 
Contact: contact@hubsai.net
 
Join us to help shape the future of SocialFi!
 
Payment in Crypto
19,000-22,000
Monthly
See details

Junior / Middle Metaverse Developer (Unity / Web3 / VR)

Manzhouli, China
Manzhouli, China
Full time
Remote
We are looking for a Metaverse Developer to help build interactive virtual environments and immersive digital experiences. The role involves developing 3D worlds, integrating Web3 technologies, and working with modern tools for real-time applications.
You will work with Unity, WebGL, and blockchain technologies to create engaging metaverse features and optimize them for performance across different devices. The developer will collaborate with designers and backend engineers to deliver scalable and stable products.
Requirements include experience with Unity and C#, understanding of 3D development, Web3 or blockchain basics, and familiarity with Git and API integration. Experience with VR/AR, NFTs, or multiplayer systems is a plus.
We offer remote work, flexible hours, crypto payments, and the opportunity to build innovative metaverse products.
Payment in Crypto
1,500-3,500
Monthly
See details

Web3 Fullstack Developer

Part time
Remote
🌐 About Us
Neonflick is a tech organization specializing in Web3 development.
We believe Web3 solutions are not as popular as they could be — mainly due to complexity. Our mission is to simplify the user experience and make decentralized technology more accessible and easy to use for everyone.
🚀 About the Role
We are looking for a Web3 Fullstack Developer who is passionate about decentralized technologies and excited to contribute to building meaningful Web3 products. You will work on developing new products, improving existing ones, and fixing bugs, all while proposing innovative ideas to enhance our platform.
🔹 Responsibilities
Develop functional and user-friendly Web3 products
Improve and optimize existing products and features
Identify and fix bugs or issues in the system
Propose and implement new ideas for product development
Collaborate with the team to ensure high-quality software delivery
🔹 Requirements
Strong interest in Web3 / blockchain / decentralized technologies
Fullstack development experience (frontend + backend)
Experience with smart contracts and decentralized frameworks is a plus
Problem-solving skills and attention to detail
Ability to work independently and proactively
🔹 What You Get
Early-stage involvement in a Web3 tech organization
Influence over product development and feature design
Opportunity to build experience and a portfolio in the Web3 space
Potential long-term collaboration and future compensation as the project grows
A chance to contribute to making Web3 simpler and more accessible
⚠️ Important
This is an unpaid position. We are looking for someone motivated by vision, learning, and long-term impact rather than immediate salary.
If you are passionate about Web3 and building meaningful decentralized products, we’d love to hear from you.