Senior Software Engineer
Barcelona, Spain
Full time
Office
Compensation is not specified
Role
Software Engineer
Description
About Keyfactor
Our goal is to create a connected society built on trust, with a focus on identity-first security for both machines and humans. Keyfactor is dedicated to helping organizations quickly establish and maintain digital trust at scale. With over 1,500 trusted clients globally, we are consistently recognized as a Best Place to Work, thanks to our exceptional team nurturing our culture as we expand. We invite you to consider a future with Keyfactor!
Location: Spain; Barcelona
Experience Requirements: IC4 – Advanced
Job Function: Engineering
Employment Type: Full-Time
Industry: Computer & Network Security
Brief Overview
As a Senior Software Engineer at Keyfactor, you will be responsible for developing and maintaining software applications, implementing new features, and ensuring quality code. This role also involves collaborating with team members to design and troubleshoot complex solutions.
Key Responsibilities
- Develop, implement, and maintain software features and functions
- Conduct code reviews, pull requests, and ensure coding standards compliance
- Collaborate with cross-functional teams to solve complex problems
- Contribute to enhancing software development processes and practices
- Identify and resolve technical issues and performance bottlenecks
- Support and guide junior engineers
- Work closely with Quality Assurance teams when needed
- Participate in both internal and external product support
- Assist in technical documentation and project reporting
- Engage in Agile ceremonies and contribute to iterative development processes
Minimum Qualifications, Education, and Skills
- Bachelor’s degree in Computer Science, Engineering, or related field, or equivalent experience
- Strong background in software engineering or related field
- Strategic thinking, strong problem-solving skills, and proficiency in relevant tools and technologies
- Proficiency in design patterns, strong architectural skills, and advanced debugging capabilities
- Experience leading complex projects and driving strategic initiatives
- Ability to mentor team members, take on complex tasks, and encourage technical improvements
- Deep understanding of industry trends, company strategy, and cross-functional processes
- Extensive knowledge of software architecture principles, code optimization, and continuous integration practices
Compensation
Salary is based on experience and will be commensurate.
Culture, Career Opportunities, and Benefits
At Keyfactor, we continually strive to improve and offer opportunities for personal and professional growth. We provide a balance of autonomy and structure to foster an entrepreneurial environment that encourages creativity and innovation. Our initiatives support our special culture:
- Second Fridays (company-wide day off on the second Friday of every month)
- Comprehensive benefit coverage for you and your dependents
- Generous paid parental leave
- Employee-focused initiatives like Key Contributors & Culture Committees
- DIVERSE Commitment for inclusivity and diversity promotion
- Wellbeing resources, mindfulness app membership, Wellness Wednesdays
- Global Volunteer Day, volunteer time off, and company non-profit matching
- Unlimited time off (US) and competitive paid time off globally
- Monthly talent development and Cross Functional meetings for professional growth
- Regular All Hands meetings with group gatherings
Core Values
Our core values are central to how we operate and what we look for in every team member. They are:
- Trust is paramount
- Customers are core
- Innovation never stops, it only accelerates
- We deliver with agility
- United by respect
- Teams make "it" happen
Keyfactor is an equal opportunity employer, including veterans and individuals with disabilities.
Reasonable Accommodation: Applicants with disabilities can contact the People team for accommodation arrangements.
Stay Safe. Be Kind. Brush your hair before the Zoom call!
Skills Required
Keyfactor
Website
www.keyfactor.comCompany size
Not specified
Location
United States
Description
Not specified
Hannah Bayaras
AI-Native Full-Stack Product Engineer
Tallinn, Estonia +9
Tallinn, Estonia +9
Full time
Remote
About Us
We are an AI & Blockchain company building the financial infrastructure for the AI age. We have customers in 19 countries, and our team is an international mix of remote talents with two core locations in Singapore and Dubai.
We raised $2.8M in funding and are expanding our team, with new products across SaaS and retail. By joining now, you’ll have the unique opportunity to work directly with founders who have made multiple exits, and build the future of AI and finance.
About You
You are a full-stack product engineer who can turn ideas into products from 0 to 1, using modern agentic coding tools without losing engineering judgment. This is not a simple vibe-coding role. You need to know how to code, reason about systems, identify poor abstractions, avoid AI-generated slop, and ship software that is readable, maintainable, and useful. You should be able to sit with a product idea, identify the core user flow, design the first version, build the front end, wire up the back end, leverage AI tools aggressively, and still have the engineering judgment to know when the code is wrong.
Your Profile
Full-stack engineer with real product taste.
AI-native, but not AI-dependent.
Comfortable shipping across front end, back end, database, infra, and third-party APIs.
Able to use coding agents deeply while maintaining control over architecture and quality.
Good at detecting slop: messy code, fake abstractions, weak tests, security gaps, bad UX, and hidden complexity.
Independent, fast, curious, and comfortable with ambiguity.
Your Work
Build products and tools from scratch.
Use AI coding tools to materially increase shipping speed.
Work across React/Next.js, Node/Python, databases, APIs, authentication, cloud platforms, and similar technologies.
Turn product ideas and UX concepts into useful software with minimal direction.
We are an AI & Blockchain company building the financial infrastructure for the AI age. We have customers in 19 countries, and our team is an international mix of remote talents with two core locations in Singapore and Dubai.
We raised $2.8M in funding and are expanding our team, with new products across SaaS and retail. By joining now, you’ll have the unique opportunity to work directly with founders who have made multiple exits, and build the future of AI and finance.
About You
You are a full-stack product engineer who can turn ideas into products from 0 to 1, using modern agentic coding tools without losing engineering judgment. This is not a simple vibe-coding role. You need to know how to code, reason about systems, identify poor abstractions, avoid AI-generated slop, and ship software that is readable, maintainable, and useful. You should be able to sit with a product idea, identify the core user flow, design the first version, build the front end, wire up the back end, leverage AI tools aggressively, and still have the engineering judgment to know when the code is wrong.
Your Profile
Full-stack engineer with real product taste.
AI-native, but not AI-dependent.
Comfortable shipping across front end, back end, database, infra, and third-party APIs.
Able to use coding agents deeply while maintaining control over architecture and quality.
Good at detecting slop: messy code, fake abstractions, weak tests, security gaps, bad UX, and hidden complexity.
Independent, fast, curious, and comfortable with ambiguity.
Your Work
Build products and tools from scratch.
Use AI coding tools to materially increase shipping speed.
Work across React/Next.js, Node/Python, databases, APIs, authentication, cloud platforms, and similar technologies.
Turn product ideas and UX concepts into useful software with minimal direction.
David Rutkovsky
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.
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
Tristika Criss
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
Merklio
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
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
Milos Bogdanov
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
But specially, candidate should be native in English.
Team communication is very important.
Please bid US only
Thank you
Payment in Crypto