Senior Full Stack Engineer – Ruby /React (460)
Full time
Remote
Compensation is not specified
Role
Full-Stack Engineer
Description
Senior Full Stack Engineer (Ruby / Ruby on Rails / React)
Location: Remote
Employment Type: Full-time
About Ubiminds
Ubiminds is a GPTW-certified, people-first company that partners with American software product companies to scale their development footprint. We specialize in custom-curating Brazil’s top 5% talent to support LATAM strategies through a unique blend of staff augmentation and employer-of-record services.
We are currently supporting a U.S.-based company in broadening its engineering team with a skilled Senior Full Stack Engineer adept at working on both backend and frontend components to deliver scalable, secure, and high-quality software solutions.
Primary Responsibilities
- Develop full stack applications using Ruby, Ruby on Rails, and React.js.
- Design and implement backend services with a focus on scalability and clean architecture.
- Enhance user-facing features utilizing React.js.
- Collaborate within agile teams across the entire software development lifecycle (SDLC).
- Design and consume RESTful APIs and GraphQL services.
- Establish and maintain CI/CD pipelines leveraging tools like Docker, CircleCI, and GitHub Actions.
- Write and manage unit and integration tests.
- Implement optimal security practices, including authentication and authorization.
- Deploy, monitor, and maintain applications on cloud platforms such as AWS, Azure, or GCP.
- Work closely with cross-functional teams on project planning, design, and delivery.
Qualifications
- Minimum of 4 years of software engineering experience.
- Proficiency in Ruby, Ruby on Rails, and React.js.
- Strong grasp of full stack development principles and modern SDLC practices.
- Experience in system design and architecture emphasizing maintainability.
- Knowledge of SQL databases (PostgreSQL, MySQL) and cloud platforms (AWS, Azure, or Google Cloud).
- Familiarity with REST APIs, GraphQL, MVC architecture, and DevOps/CI/CD tools.
- Solid testing and debugging capabilities.
- Adept at implementing security best practices.
- Proficient with Git and workflows like GitFlow.
- Excellent written and verbal communication skills in English at a C1 level.
Preferred Qualifications
Experience in consumer credit, lending, loans, or insurance domains.
Perks @Ubiminds
- Collaborate with U.S.-based product teams.
- Enjoy a remote-first culture along with a provided MacBook.
- Access English lessons, referral bonuses, tech talks, and learning programs.
- Benefit from full back-office support including HR, career development, and admin services.
Apply now to advance your career as a Senior Full Stack Engineer, creating end-to-end solutions using cutting-edge technologies.
We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.
Skills Required
Ubiminds
Website
Not specified
Company size
Not specified
Location
United States
Description
Not specified
lucas martin
Senior Web3 / Crypto Trading Platform Developer
Full time
Remote
PumaPulse is launching a new standalone domain focused on building professional-grade crypto trading platforms and on-chain trading tools. We are seeking an experienced freelance Web3 developer to help design, build, and evolve a scalable trading product with commercialization potential.ResponsibilitiesDevelop crypto trading tools, bots, or SaaS platformsIntegrate with DEXs and on-chain protocols (e.g., Solana, Ethereum)Implement real-time blockchain data monitoring and trade executionEnsure security, performance, and MEV-aware designCollaborate on product roadmap, strategy, and future featuresRequirementsStrong experience in Web3 and DeFi developmentProven work with crypto trading bots or on-chain trading systemsExperience with at least one major blockchain ecosystemSolid understanding of smart contract interaction and security best practicesAbility to deliver production-ready code and communicate clearlyNice to HaveExperience productizing tools into SaaS platformsBackground in advanced trading strategies or MEVPrior work with VC-backed or early-stage Web3 projectsEngagementFreelance / contract roleCompetitive compensation based on experiencePotential for long-term collaborationApply with relevant Web3 projects, GitHub links, and availability.
Payment in Crypto
Austin Smart
Fullstack Developer Needed for Web3 Prediction Market Platform
Brooklyn, USA
Brooklyn, USA
Full time
Remote
Summary
We're looking for an experienced Blockchain / Full-Stack Developer to help build a production-ready MVP for a Web3 prediction marketplace.
We’ve already built a basic UI prototype using vibe coding. The goal now is to turn this prototype into a functional, scalable dApp with clean architecture and solid Web3 fundamentals.
This is not a tutorial or experimental project — We’re looking for someone who has real experience shipping blockchain/web3 products.
What You’ll Do
Review and improve an existing UI prototype
Build smart contract logic for a prediction marketplace MVP
Integrate blockchain functionality with the frontend
Develop backend / API logic as needed
Ensure clean, maintainable, production-ready code
Collaborate on product decisions and MVP scope
Tech Stack (Preferred)
Frontend: Next.js / React
Backend: Node.js
Blockchain: Solidity / Rust
Experience with non-EVM chains is a plus (open to discussion)
What We're Looking For
- Strong experience in Blockchain & Web3 development
- Proven ability to build production-ready dApps
- Proficiency in Next.js, React, and Node.js
- Experience designing and shipping MVPs
- Good communication and ability to work independently
Nice to Have
- Previous work on prediction markets, DeFi, or marketplaces
- Experience taking projects from prototype to launch
- Performance, security, and scalability mindset
How to Apply
Please include:
- A brief summary of your Web3 experience
- Links to previous dApps or blockchain projects
- Your preferred tech stack and availability
If you’re an expert in blockchain and Web3 and enjoy building real products from early prototypes, We’d love to hear from you.
We're looking for an experienced Blockchain / Full-Stack Developer to help build a production-ready MVP for a Web3 prediction marketplace.
We’ve already built a basic UI prototype using vibe coding. The goal now is to turn this prototype into a functional, scalable dApp with clean architecture and solid Web3 fundamentals.
This is not a tutorial or experimental project — We’re looking for someone who has real experience shipping blockchain/web3 products.
What You’ll Do
Review and improve an existing UI prototype
Build smart contract logic for a prediction marketplace MVP
Integrate blockchain functionality with the frontend
Develop backend / API logic as needed
Ensure clean, maintainable, production-ready code
Collaborate on product decisions and MVP scope
Tech Stack (Preferred)
Frontend: Next.js / React
Backend: Node.js
Blockchain: Solidity / Rust
Experience with non-EVM chains is a plus (open to discussion)
What We're Looking For
- Strong experience in Blockchain & Web3 development
- Proven ability to build production-ready dApps
- Proficiency in Next.js, React, and Node.js
- Experience designing and shipping MVPs
- Good communication and ability to work independently
Nice to Have
- Previous work on prediction markets, DeFi, or marketplaces
- Experience taking projects from prototype to launch
- Performance, security, and scalability mindset
How to Apply
Please include:
- A brief summary of your Web3 experience
- Links to previous dApps or blockchain projects
- Your preferred tech stack and availability
If you’re an expert in blockchain and Web3 and enjoy building real products from early prototypes, We’d love to hear from you.
Payment in Crypto
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