- Hourly
- Expert
- Est. time: Less than 1 month, Less than 30 hrs/week
Looking for a veteran full-stack developer with 15+ years of experience to consult on an AI integration project. Requirements: - Deep expertise in React.js and Node.js architecture. - Proven experience integrating AI/LLM APIs (OpenAI, Claude, or similar). - Ability to audit existing code and recommend scalable infrastructure. Scope: Initial consulting session with potential for ongoing development. Please share your portfolio or past AI implementation examples in your proposal.
- Hourly: $70.00 - $85.00
- Expert
- Est. time: 3 to 6 months, 30+ hrs/week
OVERVIEW We are a technical advisory firm that partners with VC-backed companies to design, build, and scale their engineering foundations. We embed with our clients as a core part of their technical team, not as outside consultants handing over a document, but as engineers who own the outcome alongside them. Our current client is a VC-backed company operating in the auto logistics space. They're at an exciting and critical stage: they have product-market fit, they have backing, and now they need to build the production infrastructure to match their ambitions. We've been brought in to lead that build, and we're looking for a senior full stack engineer to join us for it. This is a greenfield backend API platform built in TypeScript on Node.js with Express or Fastify, and you'd be involved from the very beginning. That means shaping the architecture, setting the patterns, and building something that will need to handle real production load in a fast-moving, operationally complex industry. The backend we're building needs to be reliable, well-structured, and built to grow. If you want to do meaningful backend work on a greenfield codebase, in a real industry with real complexity, working with a team that has high standards, this is the opportunity. WHAT YOU'LL BE BUILDING A production-grade backend API platform in TypeScript on Node.js, using Express or Fastify. Because we're starting from scratch, the early decisions carry significant weight and you'll be part of making them. API architecture, project structure, middleware conventions, authentication approach, error handling, observability, data access patterns: these are all on the table and we want engineers who have opinions about them informed by experience. Day-to-day you'll be writing and reviewing TypeScript, contributing to architecture and design discussions, collaborating with the team on Slack, and joining at least one Zoom sync per week with the broader team and client stakeholders. WHAT WE'RE LOOKING FOR - 5 to 10 years of professional software engineering experience with a strong backend or full stack background. Specifically: - Fluent in TypeScript with a solid working knowledge of the Node.js runtime, including async patterns, error propagation, and performance characteristics, not just the surface API - Hands-on Express and/or Fastify experience with real APIs built using them, a clear understanding of their trade-offs, and the ability to make informed structural decisions without needing to be guided - A track record of shipping and operating production systems, having been accountable for something running live, having handled production incidents, and thinking seriously about reliability, logging, and failure modes. - Comfort operating in a greenfield environment with some ambiguity, able to ask the right questions, help define what isn't yet defined, and take ownership of outcomes rather than waiting for a fully formed spec. - Strong English communication skills, written and spoken. We're a distributed team, async-first on Slack, and we interface directly with a client whose business is moving fast. Clear communication is as important as clean code US-based strongly preferred with meaningful overlap with US business hours required for team and client collaboration NICE TO HAVE - Cloud infrastructure experience (AWS, GCP, or Azure) - Familiarity with authentication protocols (OAuth 2.0, OIDC) - API versioning strategy experience - CI/CD pipeline experience - Domain familiarity with logistics, fleet management, or supply chain systems is a genuine bonus HOW WE WORK We are a tight team with high standards and low tolerance for vague communication or dropped balls. Slack is our primary channel, async-first with responsiveness expected during working hours. We sync on Zoom at least weekly, more often during active design and planning phases. We use Jira for our ticket management. You'll receive a Microsoft 365 account on hire for SSO access to all internal and client tooling from day one. We don't micromanage. What we do expect is proactive communication, early flagging of blockers, and the kind of ownership that comes naturally to engineers who treat a codebase as something worth getting right, not just getting done. On a greenfield project with a client at a pivotal growth stage, that distinction matters. HIRING PROCESS - Intro call (15 min) - the firm, the client, the project, your background, and your questions - Technical screen (if applicable, via Coderbyte) - Background check - standard criminal background check required for all hires, no exceptions - Offer and onboarding - Microsoft 365 account and full tooling access provisioned before day one HOW TO APPLY We read every proposal that makes a genuine effort. Please include: - A description of a production backend system you've built, including what it did, the scale it operated at, your specific contributions, and what decisions you made that you're proud of or would revisit today - Your honest assessment of your TypeScript and Node.js depth. We value specifics and self-awareness over a list of buzzwords Links to code, whether GitHub, open source contributions, a portfolio, or anything else that shows us how you think and work We work with companies at inflection points and we hold ourselves and the engineers we bring in to a high standard. If this project sounds like the kind of work you want to do, make that clear in your proposal and tell us why this domain, this stage, and this type of build appeals to you specifically.
- Hourly
- Expert
- Est. time: 1 to 3 months, Less than 30 hrs/week
We are looking for a senior engineer/consultant with experience building Next.js and Node.js applications hosted with AWS. The ideal candidate has worked on high-traffic sites with very large route/page counts and understands production performance, reliability, memory usage, caching, load testing, and cloud infrastructure. Experience required: Next.js / React Node.js AWS production hosting Docker/containerized deployments MongoDB OpenSearch or Elasticsearch Large-scale public sites with millions of pages We need help reviewing the application and infrastructure, identifying performance and reliability risks, diagnosing production issues, and recommending or implementing fixes. Please only apply if you have direct experience with this technology stack and websites at this scale.
- Hourly: $70.00 - $95.00
- Expert
- Est. time: More than 6 months, 30+ hrs/week
We're looking for a senior full-stack engineer to take on hands-on work across our web platform, architecting features, building APIs, and delivering polished, performant UI. Looking for someone that can do full stack but is heavy UI developmenet leaning. You'll be doing: Building full-stack features end-to-end (dashboards, booking, payments, admin tools, etc.) Modernizing existing code and reducing technical debt Node.js services, REST APIs. Performance optimization across front-end and backend CI/CD, automated testing, container-based deploys You should have: 8+ years building production web apps Strong TypeScript across a modern framework (React) Solid Node.js / Express backend experience AWS or GCP, Docker, and CI/CD experience Comfort with PostgreSQL Automated testing (Jest, Vitest, or similar) Bonus: AdonisJS, Golang
- Hourly
- Intermediate
- Est. time: 1 to 3 months, Less than 30 hrs/week
Seeking proven and Node.js development experience to build a production-ready REST API backend that will authenticate to Microsoft Power BI via Azure AD service principal, generate time-limited embed tokens for secure dashboard rendering, and retrieve real-time operational metrics from Power BI datasets using DAX queries. The system will integrate with the Anthropic Claude API using healthcare-specific system prompts, persist all analyses and audit logs in PostgreSQL with immutable compliance tracking, and deploy to Azure App Service with robust error handling, logging, and monitoring. The engagement includes full integration testing and a comprehensive security review prior to launch. ⚠️ All data in the Lovable frontend is currently generated by React components using hardcoded mock objects. There is no backend API, no database persistence, and no real data sources. This is the scope of work for your backend engineer. The primary objective for the data engineer is to deliver a secure, multi-tenant backend, replace all mocked page data with live API responses, embed Power BI dashboards with row-level security, and stand up a Claude-driven analytical agent that operates over a governed semantic model. SUCCESS CRITERIA 1. All 3 endpoints deployed and tested 2. Frontend Dashboard.tsx renders real Power BI embed 3. Frontend AIInsights.tsx displays Claude analysis 4. ActionPlanContext replaced with server-backed CRUD 5. PostgreSQL audit log captures all API calls 6. Security review passed 7. Load test: 50 concurrent users, less than 300ms p95 8. Power BI RLS verified between test orgs 9. Documentation + runbooks delivered 10. Zero unhandled errors in production 11. Launch in mid-June 2026
- Fixed price
- Expert
- Est. budget: $15,000.00
We are seeking an elite, senior-level Full-Stack Developerto engineer a high-velocity, real-time horse racing web platform from the ground up. The core application loop revolves around a fast-paced snake draft for individual horse races, complete with an integrated, synchronized sub-second live video stream of the race. Following official track results, the platform automatically executes structured financial payouts to users using Venmo/PayPal Payout rails. The entire tech stack must be built utilizing a unified all-JavaScript environment (MERN stack) optimized to eliminate database race conditions and handle volatile real-time traffic spikes. Core Key Milestones & Project Deliverables: Milestone 1: Backend Infrastructure & User Security (15%) Set up a Node.js/Express.js application environment and establish a scalable MongoDB Atlas architecture. Implement user registration, secure JWT/bcrypt authentication, profile management, and verified phone-number registration and/or email registration. Milestone 2: Sports Data Ingestion & Automation (25%) Establish integration with a third-party commercial horse racing API (e.g., Equibase or Sportradar). Build persistent background workers (using BullMQ, Redis, or Node-Cron) to automatically ingest daily race cards, scratches, gate changes, and final official race metrics. Milestone 3: Real-Time Draft & WebRTC Video Integration (40%) Develop an interactive React.js draft dashboard utilizing Socket.io for live, synchronized state management. Implement our custom mathematical snake draft logic featuring a strict 20-second user-pick countdown timer. Build server-side automatic timeout handlers to auto-assign choices if a user disconnects or freezes. Embed an ultra-low latency HTML5 video canvas layer leveraging WebRTC (via WHIP/WHEP protocols) to ingest an RTMP stream from a media server (e.g., Ant Media or Wowza) ensuring sub-500ms video playback. Milestone 4: Venmo Payout Integration & Compliance Guardrails (20%) Seamlessly integrate the official PayPal/Venmo Payouts API to programmatically distribute money from our platform wallet directly to users' accounts and/or phone numbers. This can be worked around using a p2p format, if necessary due to compliance and regulation. Code a reliable system ledger that deducts a custom platform percentage rake prior to finalizing winner distributions. Implement an IP geo-fencing gateway (such as MaxMind GeoIP2) to block real-money contest entry from illegal jurisdictions. Technical Stack Requirements: Frontend: React.js (Next.js preferred), Tailwind CSS, Socket.io-client. Backend: Node.js, Express.js, Socket.io, Node-Cron or BullMQ.Database & Memory: MongoDB (Mongoose), Redis (for lightning-fast leaderboard and timer caching). Streaming Protocols: WebRTC, WHIP/WHEP, RTMP stream handling. Integrations: PayPal/Venmo Payouts SDK, REST/JSON Sports Data APIs, GeoIP lookup utilities. Strict Operational Code Quality Terms: 1. Repository Ownership: All codebase code and architectural modules must be pushed to our private company GitHub repository at least three times a week. Milestone releases will only be approved after clean local compilation and inspection. 2. IP Assignment: By applying for and accepting this position, you acknowledge that 100% of the developed application logic, system schemas, and code components represent a dedicated Work-for-Hire owned exclusively by the client. 3. ACID Database Transactions: You must guarantee and demonstrate via unit testing that the MongoDB schema handles marketplace swaps and concurrent drafting selections via absolute ACID Transaction Sessions to totally prevent double-spend or double-draft race conditions. To Apply, Please Answer the Following 3 Screening Questions: 1. How do you plan to structure the server environment and React architecture to keep a 30-second live countdown timer perfectly synced down to the millisecond for 4 or more different players concurrently browsing via WebSockets? 2. Please share a summary or a live link of a project you built from scratch that handled live WebRTC ultra-low-latency video delivery or complex stream handshakes. 3. What is your specific experience with financial ledger architectures? Explain how you intend to protect the MongoDB operations against multi-user transactional conflicts.
- Hourly: $40.00 - $50.00
- Expert
- Est. time: More than 6 months, Less than 30 hrs/week
We’re looking for an experienced full-stack React / React Native developer to help maintain and grow our B2B SaaS platform. Yelli is a web and mobile platform used by restaurants and hospitality businesses for training, onboarding, communication, testing, and operational documentation. The platform is already live with paying customers, and we are currently focused on improving the product, shipping new features, and scaling the platform. This is not a greenfield project. You'll be stepping into an existing codebase and working directly with the founder to improve, maintain, and evolve the product. Tech Stack: - Node.js - TypeScript - React - React Native - MySQL - AWS (EC2, S3, CodeDeploy) - Firebase - GitLab CI/CD What You'll Be Doing: - Maintaining and improving an existing web and mobile application - Fixing bugs and troubleshooting production issues - Shipping new features and enhancements - Reviewing existing architecture and suggesting improvements - Participating in weekly planning and progress meetings - Communicating progress and blockers proactively - Taking ownership of assigned projects from start to finish What We're Looking For: - 5+ years of professional full-stack development experience - Strong experience with React and React Native - Strong Node.js and TypeScript experience - Experience working with AWS-hosted applications - Experience with MySQL and relational database design - Comfortable working within an existing codebase - Strong debugging and problem-solving skills - Excellent written and verbal English communication - Reliable, responsive, and self-directed Bonus Points - SaaS startup experience - Hospitality or restaurant technology experience - UI/UX experience - Experience leading projects or mentoring developers - DevOps or infrastructure experience !!Important!! Communication is extremely important for this role. We are looking for someone who can communicate clearly, participate in weekly video meetings, explain technical decisions in plain English, and provide consistent updates on progress and blockers. Engagement Details: - Part-time freelance to start - Approximately 10–20 hours per week - Long-term opportunity for the right person - Direct relationship with the company (no agencies or subcontracting) When applying, please include: - A brief summary of your React Native experience - A SaaS product you've worked on that is currently live - Your availability (hours per week) - Your hourly rate - Why you think you'd be a good fit for this role Please do not use AI-generated proposals. We are looking for thoughtful, personalized responses that demonstrate relevant experience.
- Fixed price
- Intermediate
- Est. budget: $100.00
I'm looking for a freelancer to build a small web page where users can submit a recipe and browse recipes shared by others. Nothing complex — just a clean way to add and view recipes. Requirements: Mobile-friendly, works well on phones A submission form: recipe title + ingredients + short instructions + optional photo A page that displays all submitted recipes in a simple card layout Clean, simple, easy-to-read design Preferred stack: React (frontend) Node.js (backend) Any cloud storage for the photos Small project with a clear scope. Please share similar work, your estimated timeline, and your price.
- Fixed price
- Expert
- Est. budget: $300.00
Important: Our website consists of JavaScript-rendered pages, and we are implementing Prerender.io to serve pre-rendered HTML versions to search engine crawlers for improved indexing and SEO performance. We are only interested in candidates who have direct, hands-on experience successfully installing and configuring Prerender.io in a production environment. Project Overview We operate a large content-driven website containing approximately 300,000 pages. We need an experienced developer to implement, configure, test, and optimize Prerender.io within our AWS infrastructure. Responsibilities Install and configure Prerender.io Configure crawler detection and prerendering rules Set up and optimize caching strategies Configure AWS infrastructure to support prerendering at scale Ensure proper indexing by Google, Bing, and other search engines Test and validate rendered output across page types Optimize performance and minimize rendering costs Document implementation and deployment processes Troubleshoot rendering and indexing issues Current Tech Stack Infrastructure AWS CloudFront Route 53 EC2 / ECS S3 CloudWatch Backend Node.js Express.js REST APIs Frontend React JavaScript / TypeScript Data MongoDB PostgreSQL Required Experience Must have previously installed and configured Prerender.io in production Strong AWS architecture and deployment experience Experience supporting large websites (100,000+ pages preferred) Technical SEO expertise related to JavaScript-rendered websites Experience with React and Node.js applications Knowledge of CloudFront caching and CDN optimization Strong troubleshooting and performance optimization skills To Apply Please provide: Details of your Prerender.io implementation experience Links or examples of websites where you implemented it Relevant AWS experience Your proposed implementation approach Estimated timeline and availability Applications without prior Prerender.io implementation experience will not be considered.
- Hourly: $40.00 - $60.00
- Intermediate
- Est. time: 3 to 6 months, Less than 30 hrs/week
I’m looking for a developer to help me build a platform that predicts World Cup match results and refines those predictions with real-time data. The project will involve leveraging AI algorithms, machine learning models, historical match data, player stats, and live performance metrics to create accurate match predictions. The platform will need to continuously update and vet these predictions based on new data as the tournament unfolds. If you're passionate about soccer, AI-driven solutions, and real-time systems, this could be an exciting challenge for you. The role will involve developing a scalable platform using technologies like React, Node.js, and possibly Python for data analysis and machine learning. You'll integrate real-time data through APIs to pull match stats and player performance information. AI will be central to the prediction system, with algorithms that analyze historical trends and live data to improve accuracy. You’ll also create a vetting process to ensure predictions remain sharp and reliable as the tournament progresses. The platform must be able to handle high traffic during live events while offering a seamless user experience. I’m looking for someone with experience in AI-based prediction systems, strong web development skills (React, Node.js), and familiarity with working with APIs for real-time data integration. If you have a background in machine learning, real-time data processing, and sports analytics, that would be a major plus.