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
Emir Hammami
Looking for a blockchain developer
Whiteman Air Force Base, USA
Whiteman Air Force Base, USA
Full time
Remote
We are looking for a skilled Full-Stack Blockchain Developer to help maintain, improve, and extend the RaiseHive platform. This role involves working across the frontend, backend, and smart contract layers to ensure a stable, secure, and scalable Web3 application.
The ideal candidate has hands-on experience with React, Node.js, Ethereum smart contracts, and real-world Web3 integrations.
Framework: React 18.2 (Vite 3)
Styling: Tailwind CSS 3.4, NextUI
Animations: Framer Motion
Web3: Thirdweb SDK v4, Ethers.js v5
Routing: React Router DOM v6
State Management: React Context API
Libraries: React Markdown, React Image Gallery, Replyke (comments), React Toastify
Runtime: Node.js
Framework: Express.js
Database: MongoDB Atlas (Mongoose ODM)
Email: Nodemailer
Scheduling: Node-cron
Logging: Pino
Network: Ethereum
Smart Contracts: Solidity ^0.8.19
Development Tools: Hardhat
Libraries: OpenZeppelin, Thirdweb Contracts
Wallet Integration: MetaMask
Frontend
Strong proficiency in React (hooks, context, routing)
Experience with Vite or modern build tools
Solid knowledge of Tailwind CSS and responsive design
Experience using component libraries (NextUI, Material UI, etc.)
Backend
Strong experience with Node.js and Express
Proficiency with MongoDB and Mongoose
REST API design and implementation
Environment configuration and deployment awareness
Blockchain & Web3
Hands-on Ethereum development experience
Solidity smart contract development
Experience with Ethers.js / Thirdweb SDK
Understanding of smart contract security and gas optimization
MetaMask wallet integration and transaction handling
General
JavaScript (ES6+)
Git version control
Async programming and debugging skills
Strong problem-solving ability
The ideal candidate has hands-on experience with React, Node.js, Ethereum smart contracts, and real-world Web3 integrations.
Framework: React 18.2 (Vite 3)
Styling: Tailwind CSS 3.4, NextUI
Animations: Framer Motion
Web3: Thirdweb SDK v4, Ethers.js v5
Routing: React Router DOM v6
State Management: React Context API
Libraries: React Markdown, React Image Gallery, Replyke (comments), React Toastify
Runtime: Node.js
Framework: Express.js
Database: MongoDB Atlas (Mongoose ODM)
Email: Nodemailer
Scheduling: Node-cron
Logging: Pino
Network: Ethereum
Smart Contracts: Solidity ^0.8.19
Development Tools: Hardhat
Libraries: OpenZeppelin, Thirdweb Contracts
Wallet Integration: MetaMask
Frontend
Strong proficiency in React (hooks, context, routing)
Experience with Vite or modern build tools
Solid knowledge of Tailwind CSS and responsive design
Experience using component libraries (NextUI, Material UI, etc.)
Backend
Strong experience with Node.js and Express
Proficiency with MongoDB and Mongoose
REST API design and implementation
Environment configuration and deployment awareness
Blockchain & Web3
Hands-on Ethereum development experience
Solidity smart contract development
Experience with Ethers.js / Thirdweb SDK
Understanding of smart contract security and gas optimization
MetaMask wallet integration and transaction handling
General
JavaScript (ES6+)
Git version control
Async programming and debugging skills
Strong problem-solving ability
Payment in Crypto
Ismail Ahmad
Senior iOS developer for GameDev startup
Full time
Remote
Game Concept: “Reflex Arena”
Genre
Real-time competitive 1v1 / 2v2 skill-based action game
Platform
iOS (iPhone first, iPad optional)
Core Idea
A pure skill game where players compete in short, intense arena matches using precision timing, reflexes, and positioning — no RNG, no pay-to-win.
Each match lasts 60–90 seconds, making it ideal for mobile sessions while supporting competitive depth.
Core Gameplay Loop
Matchmaking
Skill-based MMR
Ranked & unranked queues
Arena Match
Small symmetrical arena
Players control a single character
Objective: score points by outplaying, not overpowering
Score & Progress
Win → rank up
Lose → learn (clear replay & stats)
Cosmetics only progression
Controls (Mobile-First, High Precision)
Left thumb: Movement (virtual joystick)
Right thumb: Aim + action swipe
Tap: Ability activation
Perfect timing windows reward precision (parries, counters)
👉 Designed to feel closer to a fighting game than a casual mobile title.
Mechanics (Skill > Stats)
Core Mechanics
Dash with cooldown (positioning skill)
Timed parry (frame-perfect defense)
Charged shots (risk vs reward)
Combo chaining (execution mastery)
No Randomness
Fixed damage
Fixed cooldowns
No crit chance
No loot boxes
Competitive Depth
Skill Expression
Reaction time
Prediction & mind games
Spacing & arena control
Cooldown tracking
Skill Ceiling
Easy to learn (1 minute)
Hard to master (1000+ matches)
Game Modes
Ranked Duel (Main Mode)
1v1
Best of 3 rounds
Seasonal leaderboard
Team Arena
2v2 coordinated play
Shared objectives
Training / Practice
Frame timing visualizer
Ghost replays of top players
Visual Style
Clean, minimalistic sci-fi arenas
High contrast for readability
60–120 FPS target (ProMotion)
👉 Performance clarity > visual noise.
Monetization (Fair & Competitive)
Skins (characters, arenas, effects)
Emotes / victory poses
Battle pass (cosmetic only)
🚫 No power boosts
🚫 No energy timers
🚫 No loot RNG
Technical Design (iOS-Optimized)
Native Swift
Metal / SpriteKit
Deterministic simulation
Server-authoritative logic
Rollback netcode (if real-time PvP)
Genre
Real-time competitive 1v1 / 2v2 skill-based action game
Platform
iOS (iPhone first, iPad optional)
Core Idea
A pure skill game where players compete in short, intense arena matches using precision timing, reflexes, and positioning — no RNG, no pay-to-win.
Each match lasts 60–90 seconds, making it ideal for mobile sessions while supporting competitive depth.
Core Gameplay Loop
Matchmaking
Skill-based MMR
Ranked & unranked queues
Arena Match
Small symmetrical arena
Players control a single character
Objective: score points by outplaying, not overpowering
Score & Progress
Win → rank up
Lose → learn (clear replay & stats)
Cosmetics only progression
Controls (Mobile-First, High Precision)
Left thumb: Movement (virtual joystick)
Right thumb: Aim + action swipe
Tap: Ability activation
Perfect timing windows reward precision (parries, counters)
👉 Designed to feel closer to a fighting game than a casual mobile title.
Mechanics (Skill > Stats)
Core Mechanics
Dash with cooldown (positioning skill)
Timed parry (frame-perfect defense)
Charged shots (risk vs reward)
Combo chaining (execution mastery)
No Randomness
Fixed damage
Fixed cooldowns
No crit chance
No loot boxes
Competitive Depth
Skill Expression
Reaction time
Prediction & mind games
Spacing & arena control
Cooldown tracking
Skill Ceiling
Easy to learn (1 minute)
Hard to master (1000+ matches)
Game Modes
Ranked Duel (Main Mode)
1v1
Best of 3 rounds
Seasonal leaderboard
Team Arena
2v2 coordinated play
Shared objectives
Training / Practice
Frame timing visualizer
Ghost replays of top players
Visual Style
Clean, minimalistic sci-fi arenas
High contrast for readability
60–120 FPS target (ProMotion)
👉 Performance clarity > visual noise.
Monetization (Fair & Competitive)
Skins (characters, arenas, effects)
Emotes / victory poses
Battle pass (cosmetic only)
🚫 No power boosts
🚫 No energy timers
🚫 No loot RNG
Technical Design (iOS-Optimized)
Native Swift
Metal / SpriteKit
Deterministic simulation
Server-authoritative logic
Rollback netcode (if real-time PvP)
Payment in Crypto
Ahn Nahm
Rust/blockchain
Houston, USA
Houston, USA
Part time
Remote
I am seeking a world-class Systems Engineer / Rust Architect to build a proprietary asset extraction engine on the Solana network. This is not a "Web3 App" or a "DEX UI." This is a purely backend, low-latency machine designed to capture micro-value from market volatility.The system mimics a "digital sluice," using high-precision math to harvest fractional differences that standard rounded-math bots ignore. We are scaling from a prototype to a 30-node distributed network managing 100+ concurrent execution "hands."Core Technical RequirementsLow-Level Rust Mastery: You must be an expert in the Tokio runtime, asynchronous programming, and memory-safe mathematical operations.Solana Network Physics: Deep understanding of the Sealevel runtime, custom WebSocket/Lumen bridges, and avoiding gRPC bottlenecks.Jito & MEV Optimization: Proven experience with Jito Bundles, transaction shredding, and tip-optimization to ensure first-block inclusion.Distributed Orchestration: Ability to architect a master-node system that manages 30+ regional nodes with seamless failover and zero-loss state management.Precision Math: All logic must operate on u64 integers (Lamports) to avoid floating-point rounding errors. We do not "round" to the dollar; we capture the 9th decimal.Key ResponsibilitiesEngine Hardening: Audit and optimize the core Rust logic for 0-latency execution.Node Orchestration: Build the "Master Switch" to deploy, monitor, and update 30 nodes across global regions simultaneously.The "Tax" Logic: Implement a secure, automated "sweeper" protocol that collects fractional value from all child-nodes into a master treasury without interrupting execution.Redundancy: Ensure the system is "Anti-Fragile"—if a validator or node fails, the 50-drop safety protocol must trigger an instant failover.
Payment in Crypto
TA Quant
Frontend Developer
Full time
Remote
Create intuitive, responsive user interfaces that deliver exceptional user experiences across our platform. You'll transform designs into pixel-perfect, performant applications while ensuring smooth interactions and real-time data visualization. We're looking for developers who are passionate about user experience, have an eye for design details, and can build complex web applications that handle large datasets efficiently while maintaining responsive, accessible interfaces across all devices and browsers.
Responsibilities:
Build responsive, performant web applications
Implement designs with attention to UX detail
Integrate with backend APIs and manage application state
Ensure cross-browser compatibility and accessibility
Responsibilities:
Build responsive, performant web applications
Implement designs with attention to UX detail
Integrate with backend APIs and manage application state
Ensure cross-browser compatibility and accessibility
Payment in Crypto
TA Quant
LEAD Backend Engineer
Full time
Remote
Lead the architecture and development of our core backend systems, ensuring scalability, reliability, and performance across all services. You'll be responsible for making critical technical decisions, establishing engineering standards, and building systems that can handle massive scale. This role requires deep expertise in distributed systems, database design, and modern backend technologies, along with strong leadership skills to guide and mentor the engineering team.
Responsibilities:
Design and implement scalable backend architecture
Lead technical decisions and mentor backend team members
Optimize system performance and ensure high availability
Establish best practices for code quality and deployment
Responsibilities:
Design and implement scalable backend architecture
Lead technical decisions and mentor backend team members
Optimize system performance and ensure high availability
Establish best practices for code quality and deployment
Payment in Crypto