Backend development support connecting a web application’s API to Stripe for usage-based billing. Scope includes configuring API authentication, setting up Stripe checkout for paid access tiers, and testing the payment-to-access flow

Project Overview I have a fully functional React prototype of a proprietary web-based business tool. The prototype has been built, tested, and validated. I need a skilled developer to build the production-ready hosted version. This is a precise execution job. A detailed Developer Brief (provided after NDA) specifies every feature, field, validation rule, output format, and architectural requirement. Your job is to build exactly what is described. The Job The prototype UI is built and working. The primary work is: 1. Replacing local/browser storage with a proper cloud database 2. Building the API layer connecting the UI to the database 3. Implementing the data model, cascade logic, and validation server-side 4. Deploying to a hosted environment at my domain 5. Importing default data at launch 6. Transferring all source code and IP to me This is not a design job. The UI exists. This is a data layer and infrastructure build. Technical Requirements Frontend: React (existing prototype is React/JSX) Backend: REST API or GraphQL connecting to a cloud database Database: Cloud-hosted, persistent (Supabase preferred; alternatives considered) Hosting: Vercel or equivalent (fully documented and transferable to client) Responsive: Desktop and mobile Non-Negotiables No AI features of any kind No third-party analytics, tracking, or data collection No unapproved external dependencies Daily commits to a private GitHub/GitLab repository I own and control — from day one Fixed-price, milestone-driven contract — no hourly billing NDA required before receiving the Developer Brief or prototype IP Assignment Agreement required before work begins All work product belongs to me from the moment it is created What I’m Looking For Strong React experience Solid Supabase or equivalent backend experience Someone who reads specs carefully and builds what is written Clear communicator who flags questions early US-based preferred, but open to others with strong English and relevant experience Proposal Requirements Please submit your proposal with: Your relevant experience (React, Supabase or similar, web app builds) Examples of similar projects Your estimated price range for this type of engagement Your availability and estimated timeline Note: The Developer Brief and prototype are provided only after NDA is signed.

Job Description: We are seeking a highly experienced developer to convert a completed Figma design into a production-ready web application that can be embedded via iframe. This is an insurance quoting platform with a multi-step user flow, so performance, reliability, and clean architecture are critical. The application must support a seamless end-to-end experience from quote intake through binding and confirmation. This is a fast-turn, high-priority project with a strict 7-day deadline. Technical Scope: Convert Figma designs into a responsive, pixel-perfect front-end Build a modular, responsive, scalable front-end architecture Develop backend to call APIs to support quoting workflow Implement multi-step form flow with validation, state management, and error handling Enable iframe embedding with proper handling of: Responsive resizing within iframe PostMessage communication (if needed) Optimize performance (fast load times, minimal bundle size) Deploy to production Core Functionality Requirements: Multi-step quote intake form Data capture + storage (database or structured backend) Quote summary / confirmation page Ability to expand into bind + payment flow (if not fully implemented, structure should support it) Admin/back-end access to view submitted quotes (light dashboard or database access is acceptable) Technical Requirements: Strong experience with React / Next.js (or similar modern framework) Backend/API development experience (Node.js, Express, serverless functions, etc.) Experience building embedded applications (iframe environments) Understanding of CORS, security best practices, and session handling Experience with form-heavy applications and user workflow optimization Ability to structure code for scalability and future API integrations Nice to Have: Experience with insurance, fintech, or quoting systems Experience integrating third-party APIs (rating engines, payments, CRM) Project Details: Timeline: 7 days (strict, non-negotiable) Start: Immediate Budget: Flat fee – please include total cost in your proposal Communication & Process: Daily progress updates required Ability to collaborate quickly and make real-time adjustments Clear documentation and clean code expected Next Steps / Application Requirements: Please include the following in your proposal: Relevant project examples (especially embedded apps or iframe-based tools) Your proposed flat fee Confirmation you can meet the 7-day deadline Your availability over the next 7 days We would like to get on a call to discuss the project immediately upon reviewing your proposal.

We are looking for a highly experienced senior full-stack developer to take over and continue building an existing custom web platform. This is a takeover + completion role, not a ground-up build. We need someone who can understand a complex system quickly, interpret product vision accurately, and deliver fully functional features the first time with minimal back-and-forth. About the role We are building a multi-user digital platform ecosystem with: role-based user dashboards content and discovery systems saved content / collections functionality marketplace-style interactions between users search and filtering systems structured user profiles and matching logic A significant portion of the platform is already built. The current challenge is not design — it is true functionality, system completion, and reliability. What you will do Take over an existing codebase from a previous developer Understand the full platform quickly without extensive hand-holding Identify what is incomplete, broken, or not functioning correctly Fix and complete core platform functionality Improve search, filtering, and marketplace discovery logic Ensure all features actually work end-to-end (not just UI) Double-check your own work before submission Build with stability, accuracy, and production readiness in mind Key focus areas Marketplace functionality between multiple user types Search and filtering system (accuracy + relevance are critical) Role-based dashboards and permissions User discovery / matching logic Content feed and engagement features Saved content / collections system Messaging or interaction systems between users Admin/owner control features Must-have experience We are ONLY looking for senior-level developers with proven experience in: Full-stack web application development Marketplace platforms OR multi-user systems Search / filtering / discovery systems Working inside existing codebases (not just building from scratch) Backend + frontend integration Database design and structured data systems Debugging and completing incomplete platforms Ideal candidate You are a strong fit if you: Can quickly understand large, complex platforms Have built or improved marketplaces, SaaS tools, or social platforms Think in systems and workflows, not just individual pages Take ownership of functionality (not just code delivery) Test and verify your own work before submitting Prefer fixing and improving over rebuilding from scratch Can translate non-technical vision into real working systems Important expectations This is NOT a simple website build This is NOT a design-focused project This is NOT a rebuild from scratch You must be comfortable inheriting existing work You must ensure features are fully functional before delivery Accuracy and reliability are more important than speed alone We are looking for someone who can own the functionality layer of a complex platform. Please include in your proposal Examples of marketplace, SaaS, or multi-user platforms you have built or improved Examples of projects where you inherited an existing codebase How you approach understanding a large unfamiliar system How you ensure your work is fully functional before delivery Your experience with search, filtering, or discovery systems Your availability for the next 4–6 weeks Bonus (strongly preferred) Experience improving search or ranking systems Experience with marketplace discovery flows Strong backend architecture experience Startup experience working under fast timelines Strong attention to detail and QA mindset

About the Role We are a funded fintech startup building a first-of-its-kind platform at the intersection of digital banking and social media intelligence. Think credit scoring — but for creators and entrepreneurs. Our platform combines financial tools, OAuth-connected social data, and a proprietary scoring engine into a seamless product used by creators, small business owners, and entrepreneurs. We are looking for a Senior Full-Stack Developer to own our entire technical stack — from server infrastructure to front-end experience — and help us scale from beta into a full product launch. This is not a freelance gig. This is a full-time salaried role with real equity potential at an early-stage company that is actively raising its seed round. You will be the technical backbone of the company. You will work directly with the founding team. What You Will Be Working On A PHP/Laravel API backend serving a multi-app ecosystem across production, staging, and demo environments A vanilla JS + HTML/CSS front-end for a consumer-facing creator dashboard, public profile pages, and a verification system A proprietary scoring engine that processes consented, first-party OAuth data from platforms including X/Twitter, Instagram, TikTok, LinkedIn, and YouTube A digital banking portal for investor and user financial management (Mercury, Dwolla, Stripe integrations) A server infrastructure running on a dedicated Hetzner bare-metal server (Ubuntu 24, Plesk, Apache, MySQL, Redis) that you will own end to end An admin dashboard for internal team operations — user management, lending, capital, communications Upcoming work: CI/CD pipeline implementation, Redis migration to internal infrastructure, TikTok and Meta OAuth API wiring, mobile-responsive passes, and banking partner integration The Stack Backend: PHP 8.x / Laravel, MySQL, Redis Front-End: Vanilla JavaScript, HTML5, CSS3 (no framework — clean component-based architecture) Infrastructure: Ubuntu 24.04, Plesk Obsidian, Apache, Hetzner dedicated server Integrations: OAuth 2.0 (X, Instagram, TikTok, LinkedIn, YouTube), Dwolla, Mercury, Twilio, Firebase, Stripe, Shopify Version Control: GitHub (org-based, branch workflow) Other: QR code generation, real-time verification systems, social data normalization What We Are Looking For Must-haves: 5+ years of full-stack development experience Strong PHP/Laravel — you can read, debug, and architect Laravel apps without hand-holding Solid vanilla JavaScript — you do not need React or Vue to build clean, fast, interactive UIs Comfortable owning server infrastructure — SSH, Linux, Plesk or cPanel, Apache config, MySQL administration Experience with OAuth 2.0 integrations — connecting to social media platform APIs is second nature Familiarity with fintech concepts — payments, banking APIs, KYC/AML flows, or financial data handling Git workflow discipline — clean commits, branch management, no cowboy pushes to main Strong written communication — you document your work, you write clear commit messages, you can explain architecture decisions to non-technical stakeholders Strong pluses: Experience at a fintech startup or financial technology company Familiarity with social media platform developer programs (X API, Meta Graph API, TikTok for Developers) Experience setting up CI/CD pipelines (GitHub Actions, Forge, Envoyer, or similar) Experience with Redis configuration and migration Any background in credit scoring, data normalization, or analytics engine architecture Prior W-2 employment experience (this is not a 1099 contractor role) What You Get Full-time salaried position — compensation discussed during interview based on experience Direct access to and collaboration with the founding team The opportunity to be the lead technical voice at a company that is actively fundraising and preparing for a full public launch A codebase that is real, live, and in use — not a greenfield project, not a prototype Remote-first culture — flexible hours, async-friendly, results-driven What This Is Not This is not a short-term project or hourly contract This is not a role where you will be handed a spec and left alone This is not a company where the tech is an afterthought — the product IS the technology

⭐ JOB AD: Full Stack Java Developer (Hybrid – NJ Office Required for Initial Paid Assessment) Location: Mountain Lakes, NJ (Initial in‑office assessment required) Type: Contract → Long‑Term / Hybrid Compensation: Competitive, based on experience and performance We are expanding our engineering team as we scale our Revenue Generation Engine (RGE) and Autonomous OS — advanced AI-driven systems powering multiple client platforms. We are seeking a Full Stack Java Developer who is comfortable working across modern backend and frontend stacks, and who can execute clean, efficient, and secure development workflows. This role begins with a paid, in‑office technical assessment at our private NJ development office. This is standard procedure due to the sensitive nature of our systems and the proprietary architecture we maintain. ⭐ What You’ll Do (Initial Assessment Project) The first assignment is a small, well‑defined technical task designed to evaluate your baseline competency with standard development tools and workflows: - Setting up and running a project locally - Working with GitHub repositories - Re-establishing deployment pipelines (e.g., Netlify or similar) - Ensuring clean builds and proper CI/CD functionality These are foundational skills expected of any experienced developer. Successful completion unlocks access to larger, ongoing AI and enterprise projects. ⭐ What We’re Looking For - Strong experience with Java, Spring Boot, REST APIs, Microservices - Solid understanding of React/Angular, modern front-end workflows - Comfort with GitHub, CI/CD, cloud deployments (Netlify, AWS, GCP, Azure) - Ability to work efficiently, follow structured processes, and deliver clean execution - Professionalism, reliability, and strong communication - Ability to work on-site for the initial assessment (required) - Availability for hybrid or remote work afterward (project-dependent) ⭐ Why Work With Us - We are scaling rapidly and onboarding multiple developers - You will work directly with our architecture and AI systems team - Opportunity to grow into long-term, high-impact roles - Exposure to cutting-edge AI automation and enterprise-level systems - Competitive compensation with performance-based advancement - A culture focused on speed, precision, and innovation ⭐ How to Apply Please send: - Your resume or LinkedIn profile - Your standard rate (hourly or fixed) - Your availability for the in‑office paid assessment in Mountain Lakes, NJ Office We are moving quickly and evaluating candidates on a rolling basis.

We are looking for an experienced Full Stack Developer to help build and enhance a custom business web application with admin dashboard functionality, user management, API integrations, database-driven features, and a modern responsive frontend. This is not a SaaS project. The application is a custom internal/business platform designed to improve operations, manage users, organize data, connect third-party services, and provide a clean dashboard experience for internal teams and business users. The ideal developer should be comfortable working across the full stack, from frontend UI development to backend API architecture, database structure, authentication, role-based access, third-party integrations, and deployment support. Key responsibilities include: • Build and improve custom web application features • Develop clean, responsive frontend interfaces • Create and enhance admin dashboard functionality • Implement user management and role-based access control • Build secure backend APIs and database-driven workflows • Connect third-party APIs and business tools • Create forms, filters, tables, reports, and dashboard views • Improve application performance and user experience • Work with authentication, authorization, and protected routes • Support deployment and final project handoff • Document completed work and technical decisions Required skills: • Full Stack Development • Web Application Development • React.js • Next.js • Node.js • Express.js • TypeScript • JavaScript • REST API Development • API Integration • Admin Dashboard Development • User Management • Role-Based Access Control • Database Management • PostgreSQL / MongoDB / MySQL • Responsive Web Design • Git / GitHub Nice to have: • Experience building business management platforms • Experience with internal tools and admin dashboards • Experience with CRM, payment, email, or third-party integrations • Experience with AWS, Docker, CI/CD, or deployment workflows • Strong understanding of clean, scalable application architecture • Ability to work independently and provide clear progress updates Project expectations: We are looking for someone who can take ownership of assigned features, understand business requirements, and deliver clean, maintainable, production-ready work. The right developer should be able to think beyond individual tasks and help suggest better ways to structure features, improve workflows, and create a more reliable application. This project may include ongoing work if the initial collaboration goes well, including additional features, dashboard improvements, API integrations, automation workflows, and long-term application enhancements. To apply, please include: - Your experience with custom web applications - Examples of admin dashboards or internal tools you have built - Your strongest frontend and backend stack - Your experience with API integrations - Your availability this week We are looking to start soon and would prefer someone who can communicate clearly, work independently, and deliver high-quality full stack development work.

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.

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.

We are building a production SaaS platform called MarketLens, designed for investment teams and analysts who need real-time market intelligence combined with AI-generated insights and portfolio tracking tools. What You’ll Do - Build and maintain the core backend services in Python (FastAPI / Django) - Develop frontend dashboards using React (TypeScript preferred) - Integrate real-time data pipelines (WebSockets, streaming APIs, or message queues) 1. Implement AI features such as: 2. Market summarization using LLMs 3. Portfolio risk explanations 4. Automated insight generation from time-series data - Design and maintain scalable APIs for analytics and user data - Work on subscription and billing logic (Stripe integration) - Improve system performance, especially around data freshness and dashboard latency - Participate in architecture decisions for scaling AI + data workloads Our clients are small to mid-sized hedge funds and financial advisory teams who currently rely on fragmented tools like Bloomberg exports, spreadsheets, and separate analytics dashboards. MarketLens aims to unify all of this into a single workflow.