I’m looking for a Senior Flutter/Firebase Technical Advisor to perform an independent review of my existing mobile application. The app has already been built by another developer. I’m not looking for someone to rebuild it—I need an experienced engineer to evaluate the codebase, architecture, GitHub, Firebase, security, scalability, documentation, and maintainability, then explain the findings in plain English. The goal is to determine whether another senior engineer could easily take over the project if needed and identify any potential risks or improvements. Initial engagement will be approximately 3–5 hours with the potential for an ongoing advisory relationship.

We're building Stockyard — a simple, one-stop online sale directory and CRM for ranchers. Think of it as a modern digital version of the old-time stockyard, where buyers, sellers, and animals all found each other in one place. What we already have: Visual mockups created with an AI site builder (style reference, not final specs) A domain name, ready to point to your build What we need: a full-stack developer who's also comfortable making solid design decisions — filling gaps in typography, spacing, and component states using our mockups and palette as a foundation, not a strict spec. This is development-first work, but design judgment matters. Scope of work (MVP): User accounts (simple signup/login) Directory module: listing creation/editing, search/filter by species, location, and price, buyer-seller messaging CRM module: herd/inventory tracker, auto-populated contact book, manual contact entry Consistent application of our palette/style across the whole app, not just the pages we mocked up Mobile-responsive (many users will be on phones, often outdoors or on weak signal) Deployment to our existing domain Process: we'd like an early checkpoint — homepage plus one core listing page — reviewed before you build the rest, so we align on direction early rather than at the end. What we'll provide: AI-generated mockups (style reference) Domain access Product roadmap for MVP vs. future phases Direct access to the founder throughout Ideal candidate: Full-stack experience (frontend, backend, database) A portfolio showing you can make reasonable design decisions when specs are incomplete, not just pixel-perfect implementation from finished designs Comfortable proposing alternatives if something in the mockups isn't practical to build Marketplace or CRM app experience a plus

I need help with NFC Tag integration with an existing software

**SUI WALLET DEVELOPER WANTED** ### Help Build the Wallet for a New Shared Engagement Platform **The Fusion Xchange** is building a community engagement platform that connects businesses, patrons, community partners, and sponsors through a shared rewards ecosystem. We are looking for an experienced developer—or small development team—to **adapt an existing open-source Sui wallet** for the Fusion Xchange MVP. ### THE PROJECT Rather than building a wallet from scratch, we want to start with a proven open-source Sui wallet and customize it around a simple consumer experience. The blockchain should largely disappear from the user's perspective. **Patron Wallet** * Simple onboarding * Fusion/Fuze balance * Earn rewards through QR interactions * Redeem rewards with participating businesses * View available Earn and Redeem offers * View activity and transaction history * Display Fusion NFTs/receipts without exposing unnecessary Web3 complexity **Merchant Functions** * Merchant authentication * Create and manage Earn offers * Create and manage Redeem offers * QR-based patron interactions * Verify transactions * Receive redemption vouchers/receipts * Transaction and campaign history **Sui Integration** * Sui wallet/account infrastructure * Move smart-contract interaction * Programmable transaction blocks * On-chain reward transfers * NFT/object creation and transfer * QR-triggered transactions * Sponsored/gasless transaction strategy where appropriate ### WHO WE'RE LOOKING FOR Strong candidates will have experience with some combination of: **Sui • Move • TypeScript • Rust • Flutter/React Native • Mobile Wallets • Web3 UX • QR Transactions • NFTs/Digital Assets** Direct Sui wallet development experience is highly desirable. ### WHAT MATTERS MOST We're not looking to build another crypto wallet. We're looking to create a **simple consumer wallet powered by Sui where the technology stays behind the experience.** The MVP will launch around a concentrated local-market pilot, with the architecture designed to support expansion into additional communities. ### INTERESTED? Please send: * Relevant Sui/Move experience * Wallet or mobile applications you've built * GitHub/profile links * Availability * Hourly rate or preferred project structure * Your recommendation for the open-source Sui wallet you would use as the starting point **The Fusion Xchange** **A Shared Engagement Platform** *Where businesses, patrons, community partners, and sponsors achieve more together.*

Hey there, we're Mastic, an award-winning digital consultancy and production studio. We're seeking support for a new client project that has onboarded with us. The right candidate is a skilled JavaScript developer with experience specifically with Flutterflow, React, and Dart packages. The ideal candidate should have a strong understanding of API scripting and database design, as well as proficiency in backend development tasks. You will be responsible for creating and managing server-side applications, integrating APIs, and ensuring optimal database performance. If you are passionate about building scalable and efficient applications, we would love to hear from you. A mutual NDA agreement is required to work on this project, as we have to meet our client's standard for privacy. If all of that sounds good to you, we encourage you to apply. At this time, we are only looking for freelancers to add additional support to our current team. We are not looking for an agency partnership at this moment.

U.S.-BASED APPLICANTS ONLY I am a business owner with a few software/app projects. I understand my industries, customers, and what I need the products to accomplish, but I am not a software developer. I am looking for an experienced part-time Technical Lead / Fractional CTO who can represent my side of the development process and help manage the technical execution of my projects. This is not primarily a programming position. I already use developers for implementation. I need someone experienced enough to understand the applications, translate my business requirements into clear technical specifications, communicate directly with developers in technical terms, review their work, and tell me whether what I'm being told and delivered is correct. What I need from you Understand what I want the product to accomplish from the user's/business perspective. Turn those requirements into clear technical specifications and milestones. Communicate directly with developers and handle technical discussions that don't require my involvement. Review existing codebases, architecture, APIs, databases and deployment setups. Review proposed solutions before developers spend significant time implementing them. Review code and completed milestones and tell me whether the work is actually complete before I approve payment. Identify unnecessary rebuilds, poor architecture, security problems, technical debt or developer shortcuts. Help evaluate and interview developers when I need additional specialists. Coordinate multiple developers when appropriate. Make sure repositories, hosting, domains, databases, APIs, Apple/Google developer accounts and other critical assets remain under my company's ownership and control. Help take applications through Apple App Store and Google Play production releases when necessary. Technical background You do not need to personally be the best developer in every technology involved, but you need enough hands-on technical experience to confidently oversee developers working with technologies such as React Native, iOS/Android, JavaScript/TypeScript, Node.js/Express, APIs, databases, authentication/security, cloud deployment, PWAs, Git/GitHub, mapping/GPS, AI/LLM integrations, and App Store/Google Play deployment. Experience with logistics, transportation, mapping/navigation, marketplaces or SaaS products would be particularly valuable. Working relationship This will begin as a part-time position. I am not looking for someone doing routine programming 30–40 hours per week. I want someone I can use when I need technical leadership: reviewing a project, defining work, talking with developers, checking a milestone, resolving a technical disagreement, or helping select the right approach. Occasional face-to-face meetings are important to me. Much of the work can be remote, but I specifically want someone U.S.-based who is willing and able to meet with me periodically. When applying, please answer: Where are you physically located? Are you willing to meet with me in person periodically? Describe your experience leading or supervising software developers. Have you inherited existing applications/codebases and evaluated another developer's work? Give examples. What mobile applications have you personally helped take to production on both Apple App Store and Google Play? How comfortable are you reviewing React Native, Node/backend, database, API and cloud architecture? Describe any mapping/GPS, logistics, transportation or marketplace applications you've worked on. How do you determine whether a developer's milestone is genuinely complete before recommending that the client approve it? How would you protect a business owner from becoming dependent on a developer who controls the repository, hosting, database or other critical infrastructure? Are you comfortable communicating directly with overseas developers and leading technical calls on my behalf? Please begin your proposal with the words OWNER SIDE so I know you read the posting. I am looking for a long-term relationship with the right person who could eventually become the technical person overseeing multiple existing and future products for my companies.

This project is for the completion and launch of the existing GolgiCore MVP, a React-based Progressive Web Application (PWA), with dedicated mobile and desktop user experiences. Development has already begun. The mobile MVP Figma design is complete and the React PWA frontend is partially developed. The remaining project will be completed according to the mutually agreed GolgiCore MVP Fixed Scope Proposal. Project Scope The remaining MVP work includes: Design and approval of the desktop application in Figma Completion of the mobile MVP Completion of the desktop application Supabase authentication and shared backend/database integration Dashboard, group, folder, and document management functionality Document upload and external document-link functionality Search functionality Reminder and document-expiration system Email and in-app notifications Profile, Job Profile, account, password, and notification settings Mobile/desktop synchronization using shared backend infrastructure Security implementation and user-data isolation Testing, bug fixes, revisions, and production deployment required to satisfy the agreed acceptance criteria Architecture & Security Mobile and desktop experiences will share the same backend infrastructure, database, authentication system, APIs/server-side functionality, security architecture, storage, email services, and core business logic. Shared functionality will be reused wherever practical and will not be independently rebuilt. Security requirements include Supabase Row Level Security (RLS), user-data isolation, secure authentication/session handling, server-side authorization and validation, secure file access, protection of secrets/service-role keys, HTTPS/TLS, appropriate audit logging, protection against applicable common web vulnerabilities, and applicable backup/recovery configuration. Users must be prevented from accessing another user's records or documents through the frontend, modified URLs, direct API/database requests, storage paths, or manipulated identifiers. Fixed-Price Agreement The total fixed price for completion of the remaining agreed MVP scope is $8,000. The project will be divided into separately funded Upwork milestones based on the agreed Fixed Scope Proposal. Each milestone will be submitted for review and must satisfy its agreed deliverables and acceptance criteria before approval and progression to the next milestone. Bug fixes and revisions necessary for functionality within the agreed scope to meet the acceptance criteria are included in the fixed price. The $8,000 represents the complete remaining development cost for the agreed MVP scope. No additional development charges will be incurred unless new features, functionality, workflows, redesigns, or other requirements outside the agreed scope are requested and approved separately. The MVP will be considered complete when all agreed milestone deliverables and final acceptance criteria have been satisfied, required security controls and testing have been completed, production deployment is operational, and critical or major bugs affecting the agreed MVP functionality have been resolved.

We are an early-stage consumer technology startup preparing for product development and fundraising. Before engineering begins, we want to establish a world-class user experience and product design foundation. We are looking for a Senior Product Designer with experience designing polished consumer applications from the ground up. This engagement focuses on creating the complete product experience not simply designing attractive screens. Specific product details will be shared with shortlisted candidates during the interview process. Responsibilities You will work directly with the founder to: Understand the product vision and business goals Design the end-to-end user experience Create user flows and customer journeys Build wireframes and information architecture Design high-fidelity mobile interfaces Create a scalable design system and reusable components Build an interactive Figma prototype Prepare developer-ready design specifications Recommend UX improvements and best practices

Looking for someone to take my replit built app and optimize it, launch it on the App Store. Already have it in test flight but crashes as soon as you open the app. Need someone’s expertise to tune the app and see it to the finish line.

I am in need of an app developer to help make my idea come together. I am really into fitness but find that the meal planning and meal preparation is the hardest. My idea is to have an app that allows you to put in dietary restrictions like vegan proteins etc and then have it create a list of meals that fit that list. Then after the user selects the meals it will then create a shopping list. That’s about the gist of it.