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
xelora S
senior solidity developer
New York, USA
New York, USA
Part time
Remote
We're currently building CritiQ, an innovative insurance platform.
It's an on-chain, parametric-first insurance solution designed to deliver fast, fair, and fully transparent coverage.
Our initial offerings include Flight Delay, Smart Contract Risk, and Commercial Property insurance, with plans to expand as oracle infrastructure develops.
It's an on-chain, parametric-first insurance solution designed to deliver fast, fair, and fully transparent coverage.
Our initial offerings include Flight Delay, Smart Contract Risk, and Commercial Property insurance, with plans to expand as oracle infrastructure develops.
Payment in Crypto
SADR B
Founding Technical Partners for Oferli – Elite Web & Mobile Development Team🌐
Remote, USA
Remote, USA
Part time
Remote
I am Sadr, CEO of Oferli. We are building a high-performance, elite technical team, and I am looking for 5 to 10 dedicated founding technical partners to join me in this mission.
The Vision:
Oferli is a 100% decentralized ecosystem. While we are rooted in Web3, our expertise spans across professional web and mobile application development. We are not just another agency; we are crafting the next generation of digital solutions. Our goal is to set a new standard for excellence, transparency, and decentralization.
What I am looking for:
I am building a professional, senior-level "Elite Team." I am looking for partners who are truly passionate about the vision—not just short-term gains. By combining our individual expertise and portfolios, we will establish Oferli’s collective professional reputation.
Requirements:
Proven Expertise: You must be a senior-level professional. Please provide your portfolio showcasing your best work in web and mobile development.
Commitment: This is a founding partnership. We are looking for those who believe in the mission and are ready to tackle complex challenges together.
Professionalism: We operate with high standards. Communication and efficiency are key.
How We Work:
Collaboration: We use professional, secure channels for all communications. Qualified candidates will be contacted via email to be invited to our private workspace on Notion to align on our roadmap and launch our upcoming projects.
Decentralized Operations: We leverage Web3 tools for collaboration and compensation, maintaining a fully decentralized environment.
Growth: We are launching with a core team of at least 5 founding partners, scaling to 10, to deliver high-impact results for our clients.
Application Process:
If you are a senior professional ready to build a world-class, decentralized ecosystem, apply here on LaborX. Qualified candidates will be contacted via email for further professional vetting and onboarding.
Let’s build the future, together.
Sadr B
CEO, Oferli
The Vision:
Oferli is a 100% decentralized ecosystem. While we are rooted in Web3, our expertise spans across professional web and mobile application development. We are not just another agency; we are crafting the next generation of digital solutions. Our goal is to set a new standard for excellence, transparency, and decentralization.
What I am looking for:
I am building a professional, senior-level "Elite Team." I am looking for partners who are truly passionate about the vision—not just short-term gains. By combining our individual expertise and portfolios, we will establish Oferli’s collective professional reputation.
Requirements:
Proven Expertise: You must be a senior-level professional. Please provide your portfolio showcasing your best work in web and mobile development.
Commitment: This is a founding partnership. We are looking for those who believe in the mission and are ready to tackle complex challenges together.
Professionalism: We operate with high standards. Communication and efficiency are key.
How We Work:
Collaboration: We use professional, secure channels for all communications. Qualified candidates will be contacted via email to be invited to our private workspace on Notion to align on our roadmap and launch our upcoming projects.
Decentralized Operations: We leverage Web3 tools for collaboration and compensation, maintaining a fully decentralized environment.
Growth: We are launching with a core team of at least 5 founding partners, scaling to 10, to deliver high-impact results for our clients.
Application Process:
If you are a senior professional ready to build a world-class, decentralized ecosystem, apply here on LaborX. Qualified candidates will be contacted via email for further professional vetting and onboarding.
Let’s build the future, together.
Sadr B
CEO, Oferli
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
Marcus Lindberg
Senior Blockchain Engineer - Low-Latency Execution Infrastructure (HyperEVM / Hyperliquid)
Full time
Remote
we’re looking for a senior blockchain engineer to build low-latency execution infrastructure around hyperevm and hyperliquid-related trading systems.
this is not a frontend or dapp role. the focus is on real-time execution systems, chain-native infrastructure, and market-aware backend engineering where latency, ordering, and state correctness directly impact execution outcomes.
you will work on systems that operate under noisy, adversarial, and highly dynamic conditions, including delayed or missing websocket events, rpc inconsistencies, transaction lifecycle complexity, state desynchronization, retries, and recovery logic.
core responsibilities include building and maintaining realtime blockchain data pipelines, websocket and rpc streaming systems, execution orchestration layers, liquidity-aware routing logic, transaction lifecycle management, and integration with orderbook and market data systems.
we are specifically looking for engineers who think in systems rather than features. meaning understanding how data flows through pipelines, how state evolves over time, how failures propagate, and how to design systems that recover automatically without manual intervention.
areas of work include:
- realtime blockchain data ingestion
- mempool-aware execution flows
- transaction lifecycle handling
- execution sequencing and routing
- websocket and rpc infrastructure
- state synchronization systems
- liquidity and orderbook integration
- performance and latency optimization
you should be comfortable working with distributed systems, asynchronous event processing, and latency-sensitive backend architectures.
strong experience in one or more of the following areas is highly relevant:
- exchange infrastructure
- trading systems
- execution engines
- blockchain indexers
- realtime event systems
- arbitrage systems
- rpc/node infrastructure
- defi backend systems
- low-latency backend engineering
preferred technical stack:
- typescript / node.js
- go
- rust
- python
- postgres
- clickhouse
- redis
- kafka or similar messaging systems
- docker
- linux environments
- evm rpc internals
- websocket infrastructure
ecosystem familiarity:
- ethereum, arbitrum, base, optimism, bsc
- hyperliquid / hyperevm
- foundry
- ethers.js / viem
- geth / erigon / nethermind
- dex and amm mechanics
- liquidity math, slippage, gas strategy, routing logic
this role is not suitable for:
- frontend-only developers
- nft or basic dapp experience only
- tutorial-level web3 developers
- candidates without production systems experience
we value engineers who have built real systems where correctness, latency, and reliability matter under load. we care less about buzzwords and more about concrete systems you have personally built and operated.
ideal candidates can clearly explain:
- system architecture decisions
- bottlenecks and tradeoffs
- failure modes and recovery strategies
- latency considerations in real systems
- production debugging experience
working style:
- remote
- async-first
- low bureaucracy
- high ownership
- engineering-driven team
- direct technical communication
we strongly prefer practical engineering depth over polished presentation. if you have built or worked on systems involving realtime data, trading infrastructure, blockchain execution, or latency-sensitive backend systems, please include details of those systems when applying.
Payment in Crypto