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.

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.

Job description Corprex builds on-premises AI infrastructure for regulated enterprises. Think sovereign, private AI deployments for manufacturers, utilities, financial firms, and law firms. We keep sensitive data off the cloud entirely. We're a lean, fast-moving startup and we need a senior full stack developer to own a broad scope: our cloud-hosted SaaS portal, customer-facing dashboards, internal platform tooling, and integration work that ties into our on-prem Omega platform. You'll be working directly with the CEO. What you'll work on → Single-tenant cloud SaaS portal (new build) — the hosted version of our on-prem product → Customer-facing dashboards for AI usage, document access, and activity monitoring → REST API development and integration with our backend AI platform → Active Directory / SSO integration work for enterprise deployments → Demo environments and sales-facing tooling used in Fortune 500 prospect demos → Internal ops tooling as needed Requirements → US-based, available during Eastern or Central business hours → 5+ years full stack experience — strong backend required (Node.js, Python, or similar) → React or Next.js on the frontend → Cloud deployment experience — AWS, GCP, or Azure → Comfortable working in a startup environment with minimal oversight → Experience with enterprise auth (Active Directory, LDAP, SAML, or OAuth) is a strong plus → Prior work on AI-integrated products (RAG pipelines, LLM APIs, vector DBs) is a plus Engagement details Scope: Ongoing / retainer Hours: Part-time to full-time Location: US only To apply, answer these in your proposal 1.What's a backend-heavy project you've shipped end-to-end? Briefly describe the stack and your role. 2.Have you worked with enterprise auth (AD, SAML, SSO)? If yes, in what context? 3.What's your availability and hourly rate?

Summary Senior Full-Stack Developer with experience in JavaScript, python, nodeJS, php.

 We are building a multi-tenant AI-powered marketing operating system for SMBs. 

This is NOT an autonomous AI agent project.

 The platform uses deterministic workflow orchestration enhanced with AI services for:

* content generation,
* approvals,
* publishing,
* engagement analysis,
* brand-style learning,
* multi-platform social posting, * social media campaign.

 We need a senior engineer who understands production SaaS architecture, workflow reliability, API integrations, queues/retries, and AI integrations.

 REQUIRED EXPERIENCE:

* Multi-tenant SaaS applications
* Queue/retry systems
* Webhook reliability
* Idempotency / duplicate prevention
* API integrations (multiple social media platforms)
* Structured AI outputs (JSON schema validation)
* Background jobs / async workflows
* Production-grade backend architecture

 YOU SHOULD UNDERSTAND

* deterministic workflow orchestration,
* retries/backoff,
* distributed locks,
* tenant isolation,
* workflow state management,
* structured AI pipelines,
* cost governance,
* approval workflows.

 DO NOT APPLY IF YOUR EXPERIENCE IS MOSTLY:

* autonomous AI agents,
* chatbot-only projects,
* prompt engineering only,
* no backend SaaS experience.

 Project Scope:

* starting with 50 concurrent clients
* AI-generated social content
* approval-gated publishing
* multi-platform posting
* adaptive brand memory
* analytics + engagement tracking * paid social media campaigns

 To apply, please provide:

 1. Relevant SaaS/backend projects
 2. Experience with OpenAI structured outputs
3. Your preferred architecture approach for scalable workflow systems

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

I’m looking for an experienced Full-Stack Web Developer to help build and improve a business website while adding interactive mapping functionality. The ideal candidate should be comfortable with both front-end and back-end development and have experience integrating map-based tools into websites. What I’m Looking For: * Website design and development * Mobile-responsive layouts * Fast-loading, modern user experience * Lead capture forms * Database integration * Interactive maps * Territory or area selection tools * Location-based functionality * API integrations * Ongoing improvements and feature development Preferred Skills: * React, Next.js, or similar frameworks * Node.js or other back-end technologies * Database management * Google Maps API, Mapbox, or similar mapping platforms * UI/UX design experience * Strong problem-solving skills

Looking for a skilled full-stack developer to help build and refine an early-stage SaaS platform currently in MVP development. The platform combines guided workflows, AI-assisted functionality, user dashboards, and subscription-based features within a modern web application experience. We're looking for someone who can help transform an existing concept and partial prototype into a polished, scalable product. Ideal for developers interested in: SaaS platforms AI integrations Scalable web applications Subscription products Startup environments Responsibilities: Frontend and backend development Authentication and user dashboards Stripe/payment integration Database architecture API integrations Responsive UI/UX refinement Scalable application structure Deployment and production setup Preferred Stack: React / Next.js Node.js PostgreSQL Tailwind CSS Stripe REST APIs OpenAI or similar AI integrations Ideal Candidate: Strong full-stack development experience Experience building SaaS products Comfortable working independently Understands scalable architecture Good communication skills Startup mindset Bonus: Experience with AI-powered applications Experience with multilingual platforms Project Stage: Early-stage MVP Potential long-term collaboration Please send: Portfolio or GitHub Relevant projects Preferred stack Hourly rate or project estimate Availability

Need to get a site (already built) up and running on my web server: Able to configure DNS, IIS, ColdFusion, and psbly (not required) NodeJS. Just looking for someone to guide me through a lengthy zoom session to get it done. May involve some configuring in CloudFlare. Minimum time billed: 1 to 3 hours.

Overview I am seeking an experienced full-stack developer to build an MVP (Minimum Viable Product) for a web-based social engagement platform. The application will allow users to create content, interact with other users, participate in community-driven experiences, and view aggregated results and analytics. The project should be designed with scalability in mind, as additional features and monetization options may be added in future phases. Required Features User Accounts * User registration and authentication * Password reset * User profiles * Social login options preferred Core Platform Functionality * User-generated content * Community participation features * Search and discovery tools * Sharing functionality * User dashboards Data & Analytics * User participation tracking * Aggregated result displays * Basic analytics dashboards * Reporting functionality Administration * User management * Content moderation * Platform analytics * Administrative controls Design Requirements * Modern responsive design * Mobile-first experience * Intuitive user interface * Clean and scalable architecture Preferred Technology Stack Open to recommendations, but experience with the following is preferred: * React / Next.js * Node.js * PostgreSQL * AWS, Azure, Supabase, or Vercel * REST API or GraphQL Deliverables * Source code * Documentation * Deployment instructions * Production-ready MVP * Knowledge transfer session * Post-launch support period Proposal Requirements Please provide: 1. Similar applications you have built. 2. Recommended technology stack. 3. Estimated timeline. 4. Fixed-price milestone proposal. 5. Examples of scalable applications you have developed. 6. Experience with authentication, user-generated content, and analytics systems. Additional project details will be shared with shortlisted candidates following execution of a mutual NDA.

I need a backend developer to deploy an already-written Node.js/Express server to Railway, connect it to an existing Supabase project, and complete a third-party OAuth/webhook integration with the Garmin Connect API. This is a deployment and configuration task, not a build task. Expected time: 3–6 hours for someone experienced with this exact stack. What’s already done • Server code is fully written (Express routes for OAuth callback, webhook receiver, token refresh, deregistration) • Supabase database schema is created with tables and RLS policies • Supabase private storage bucket is created • Code runs successfully on localhost What you’ll do 1. Deploy the provided GitHub repo to a Railway project I’ve already created 2. Configure environment variables in Railway 3. Verify the deployed health check endpoint responds correctly 4. Set up a Railway Cron job for hourly token refresh 5. Provide me with three endpoint URLs to register with Garmin (I’ll handle the Garmin portal myself — you won’t need access to it) 6. Run an end-to-end smoke test using Garmin’s API testing tools to confirm the full flow works (webhook received → FIT file downloaded → stored correctly) 7. Document any bugs you find and fix What you’ll be given access to • A standalone GitHub repo (just this server — not my main app codebase) • My Railway project (Member role) • My Supabase project (Developer role) • Environment variable values, shared securely once you’re onboarded What you will NOT need or have access to • iOS app codebase • Garmin Developer Portal login • Any production user data (this is a 5-person alpha test — no real user data exists yet) • Any other part of my systems Requirements • Demonstrated experience deploying Node.js/Express apps to Railway (please share an example or describe a past project) • Experience with OAuth 2.0, ideally including PKCE flow • Experience with Postgres (Supabase or similar) including basic schema/RLS understanding • Comfortable working from a written technical brief with minimal back-and-forth • Available for a short, focused engagement — not looking for ongoing work right now (though that may be possible later if this goes well) Budget & terms • Fixed price for defined scope, paid via Upwork • Budget: $300–500 depending on experience, payable on completion of the smoke test • All access (GitHub, Railway, Supabase) will be revoked/rotated at the end of the engagement — this is standard practice on my end, not a reflection of trust To apply, please answer 1. Have you deployed a Node/Express app to Railway before? Please describe briefly. 2. Have you worked with OAuth 2.0 PKCE flows? In what context? 3. In one or two sentences: how would you handle a webhook that must respond within 30 seconds, but also needs to do slower async work (like downloading a file) afterward? 4. Your availability to start and rough timeline to complete Looking forward to hearing from you.