Mid Java Developer

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

About us:

B2C2 is a pioneering digital asset company shaping the future ecosystem.

The company facilitates institutional access to cryptocurrencies by ensuring reliable liquidity regardless of market conditions.

Built on crypto-native technology and continuous product innovation, B2C2 is the preferred partner for diverse institutions globally. Established in 2015 and later acquired by Japanese financial group, SBI, in 2020, B2C2 operates as an independent entity. With headquarters in the UK and additional offices in the US and Japan, B2C2 OTC Ltd. holds authorization and regulation from the UK’s Financial Conduct Authority (FRN 810834).

We take pride in our company culture and our ability to attract not just top talent, but the right individuals who align with our values. If you are seeking a role in a dynamic and cutting-edge industry, please continue reading.

SCOPE OF THE ROLE

This presents an exciting opportunity for successful candidates to work within one of our Java teams.

Role and Responsibilities

  • Develop and maintain efficient Java-based applications and components, ensuring high-quality code and adherence to coding standards
  • Enhance and maintain in-house shared libraries to guarantee their reliability and effectiveness
  • Produce robust, well-documented, thoroughly-tested, and maintainable code to meet project objectives and deadlines
  • Identify and resolve software defects and technical issues promptly to minimize disruption to revenue-generating processes
  • Collaborate with cross-functional teams to define and implement new features
  • Participate in code reviews, incorporating feedback to enhance code quality
  • Ensure good quality internal documentation is maintained and adhered to

Skills Required

  • 5+ years of software development experience in Java
  • Strong grasp of object-oriented programming concepts and some design patterns
  • Demonstrated ability to write clean, efficient code
  • Proficiency in writing automated tests and expanding test coverage for existing code
  • Experience in full project lifecycle ownership, from inception to delivery
  • Background in providing production support for mission-critical services
  • Strong sense of ownership, autonomy, and ability to work collaboratively across all levels of an organization
  • Excellent communication skills in both Polish and English at B2/C1 level

Skills Desired

  • Experience with asynchronous event-driven network applications based on Netty
  • Proficiency in a variety of low GC techniques in Java
  • Knowledge of relational databases, SQL, and understanding of web technologies and protocols such as HTTP and Websocket
  • Familiarity with technologies like PostgreSQL, Kafka, Redis, or gRPC
  • Some experience with Linux, Docker, Kubernetes, and/or AWS
  • Proficient in coding with Python
  • Interest in the crypto industry and/or trading

Opportunity:

  • Rapid personal growth with constant encouragement to deliver your best
  • Exposure to cutting-edge technologies and products for enhanced productivity
  • Abundant career advancement prospects within a growing organization
  • Contributing to the future of finance technology, with the chance to make a meaningful impact
  • Enjoy a dynamic work environment that balances hard work with fun
  • Biannual performance reviews and potential for discretionary bonuses
  • Empowerment to create positive changes
  • Forward-thinking and vibrant corporate culture

A strong organizational culture is a key element in the success of companies, and at B2C2, we pride ourselves on being a values-driven company. Our core values include:

  • Ambitious - Aspiring to make groundbreaking achievements
  • Innovative - Forward-thinking in solutions for clients and employees
  • Meritocratic - Recognizing and rewarding positive contributions throughout the organization
  • Collegiate - Fostering teamwork in a collaborative environment
  • Risk-Aware - Making informed decisions and practicing considered approaches

Equal Employment Opportunities Policy:

B2C2 is dedicated to promoting equal employment opportunities for all applicants and employees. We welcome individuals from diverse backgrounds. It is our commitment to conduct recruiting, hiring, training and rewards practices without discrimination based on race, color, religion, gender, national origin, age, disability, genetic information, marital status, or any other characteristic protected under relevant laws. Discrimination against any employee based on membership in a protected category is not tolerated at B2C2. We strive to foster an inclusive environment to attract, engage, promote, and retain top talent. Flexible working arrangements may be considered for any position.

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

More Full-time Jobs

Show more

Chief Technology Officer (CTO) / Senior Full-Stack Developer (Web3)

London, UK
London, UK
Full time
Remote
About the Role
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.
Payment in Crypto
7,500-11,000
Monthly
See details

Backend Engineer with hands-on blockchain experience

Full time
Remote
We are building a modern hotel booking platform enhanced with Web3 capabilities, includingtoken-based payments, on-chain verification, and decentralized identity/ownership features.We’re looking for a Backend Engineer to design and build scalable backend systems andintegrate them with blockchain infrastructure. You’ll work closely with frontend and Web3engineers to deliver a seamless and reliable platform. 
Payment in Crypto
13,000-17,000
Monthly
See details

Senior Blockchain Engineer (Cosmos SDK & IBC)

Hong Kong
Hong Kong
Full time
Remote
Merklio is expanding its cross-chain orchestration layer. We are building a sovereign app-chain (Rollup-style) that aggregates liquidity from multiple L1s via IBC. We need a Blockchain Engineer to design, implement, and maintain our Cosmos-based chain.
Expectations:
Design custom modules (x/staking, x/rewards, x/merkl)
Implement IBC light clients and relayers
Optimize block time and state pruning
Write comprehensive unit & integration tests (Go test)
Build CLI tools for validators and delegators
Monitor node health and network upgrades
Collaborate with the research team on MEV-resistant ordering
Maintain chain upgrades (v1 → v2) with migration scripts
Write technical documentation for external validators
Nice to have:
Experience with Avalanche Subnets or Polkadot Substrate
Knowledge of HSM and key management
Open-source contributions to Cosmos SDK or related repos
Chinese+English language proficiency
Payment in Crypto
7,000-10,000
Monthly
See details

Senior Mobile application developer

Full time
Remote
I am looking for a developer who has much experience in Mobile application development.
But specially, candidate should be native in English.
Team communication is very important.
Please bid US only
Thank you
Payment in Crypto
300-1,000
Monthly
See details

Web Developer

New York City, USA
New York City, USA
Full time
Remote
Hi,
I need a custom ebay like site for bitcoins or using stock credit on it. I need it to let you pay the user verbally, like an agreement you agree on that's it. I need the site fixed so it can be upgraded in the future.
I need it to be fixed so you can upload something to the site and sell it.
All I ask is keep the buying and selling part verbal agreements only. Like sending the user stock credit virtually.
Bid on things on the website 
Sell things on the website
Buy things on the website
All I ask is keep the programming simple and the website in a simple form.
I need a website for the web browser and one for the phone web browsers.
If you can put in a custom user admin for it also, then that will be great.
Thank you,
Chris Clark (666 Encryption, CEO)
 
Payment in Crypto
10,000-100,000
Monthly
See details