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We are building Pet360 SaaS Platform, the first blockchain-based pet ecosystem in Brazil (160M pets, zero blockchain infrastructure today). We are adding: • Pet NFT passports (immutable medical history) • Vaccine certificate NFTs • Smart contract adoptions • Pet insurance on-chain As we grow this project, we're expanding our team — especially looking for blockchain developers, designers, frontend engineers and full-stack engineers. This role is fully remote, but please keep in mind that we're looking for someone who can commit to more than 30 hours per week. What truly matters to us is your thinking and how you build. Compensation ranges from $20 to $60 an hour — and it's negotiable. This is a contract position, but there is strong potential for long-term collaboration and growth based on performance and how well we work together. If this sounds like something you might be interested in, I would be happy to share more details with you. Thanks
Project ID: 40446143
67 proposals
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Active 3 days ago
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67 freelancers are bidding on average $36 USD/hour for this job

With over a decade of experience in blockchain development, including expertise in Polygon, I understand the importance of integrating blockchain technology into projects like Pet360 SaaS Platform. Your goal of implementing Pet NFT passports, vaccine certificate NFTs, smart contract adoptions, and on-chain pet insurance aligns perfectly with my background in high-security systems and scalable solutions for complex projects. My strategic insight for this project would be to leverage the scalability and low transaction costs offered by Polygon to ensure efficient and cost-effective operations. I have successfully built and scaled Telegram Mini Apps serving over 1 million users, demonstrating my ability to handle high-complexity systems similar to what Pet360 requires. I encourage you to reach out so we can discuss your project roadmap in more detail. Let's collaborate to bring your vision for the first blockchain-based pet ecosystem in Brazil to life.
$40 USD in 15 days
8.8
8.8

Hello, I am a full-time senior full-stack developer with strong experience in blockchain integration, smart contracts, and scalable SaaS platforms. You can track the project’s progress using the tracker. I’m available to work 40 hours per week. I have reviewed your Pet360 project and understand the requirements clearly, including NFT pet passports, vaccine certificate NFTs, smart contract-based adoptions, and on-chain insurance workflows on Polygon. I can contribute to building secure and scalable Web3 architecture, smart contracts (Solidity), and full-stack integration for a production-ready ecosystem. I would be happy to discuss the technical architecture and next steps in detail. Thanks. >>>>>>> We'll share our portfolio in Chat. Let's talk further speak over the freelancer call or chat. <<<<<<
$25 USD in 40 days
7.0
7.0

Hi, this Pet360 project presents an interesting challenge in integrating blockchain immutability with real-world pet ecosystem data. The primary engineering risk lies in orchestrating secure, reliable smart contract interactions while maintaining data consistency between on-chain and off-chain components. I usually structure systems by separating blockchain transaction layers from backend data services to isolate complexity and improve maintainability. Though my core focus is AI and backend systems, my experience in designing robust, scalable architectures applies to handling complex data flows and ensuring system reliability. I recommend separating the smart contract logic from the user-facing API and data ingestion layers to allow independent evolution and testing. This also facilitates fallback strategies for transaction failures or network latency. While LLM reliability is not directly applicable here, similar principles of validation and fallback should be employed for blockchain event monitoring and state reconciliation. Systems like this require careful design for long-term production stability, especially given the immutable nature of blockchain data. I can help by outlining a modular ingestion and synchronization pipeline, mapping smart contract event flows, and reviewing data consistency strategies to ensure robustness. Thanks, Hercules
$50 USD in 40 days
6.8
6.8

Hi, Pet360 is exactly the kind of mission-driven Web3 platform I enjoy building. Creating NFT pet passports, vaccine certificates, smart contract adoptions, and on-chain insurance brings real utility to blockchain and solves a meaningful problem in a massive market. I have strong experience with Solidity, NestJS, frontend development, and full-stack architecture for production Web3 applications. I can help design secure smart contracts, NFT minting flows, API services, wallet integration, metadata management, and scalable SaaS features that connect blockchain functionality with a polished user experience. My focus is always on practical architecture, maintainable code, and long-term scalability. Whether implementing immutable medical records, adoption workflows, or insurance logic, I can contribute across both backend and frontend while collaborating closely with your team. I am comfortable committing 30+ hours per week and would be excited to grow with the project as it evolves. I would be grateful for the opportunity to contribute to Pet360 and will gladly accept your feedback. Best, Justin
$50 USD in 40 days
6.0
6.0

hi, i have experience building web3 platforms with smart contracts, frontend integration, and scalable backend systems. i can help build and integrate your nft based pet passports, vaccine records, and smart contract adoption flows. i will work on clean contract logic in solidity and connect it with frontend using react and web3 tools, while also supporting backend services with node or nest js for smooth data flow and scalability. i am comfortable working long term and contributing across the stack, especially in early stage products where architecture decisions matter. can we schedule a quick meeting to discuss the project in detail. it will help me understand your current setup better and how i can contribute effectively. i will also share my portfolio during the chat. mughiraa
$38 USD in 40 days
5.7
5.7

Hello! This is James from Hollywood, and I'm excited about the opportunity to work on the Pet360 SaaS platform. I've read your project description carefully and believe I have the right skills and extensive experience to help make your vision a reality. With over 15 years in full-stack development, I specialize in blockchain integration and have successfully implemented projects that utilize Solidity, Smart Contracts, and Nest.js. I'm also a Shopify partner since 2016, which means I have built numerous apps and themes on that platform. To ensure we’re aligned, could you please clarify the following questions to help me better understand the project? 1. What specific features or functionalities do you envision for the blockchain aspect of Pet360? 2. Are there any specific compliance or security standards we need to adhere to in Brazil for this project? My approach would include an initial phase to define the project scope clearly, followed by a design phase, and then the development and integration of the blockchain components. I’m committed to delivering a solution that not only meets your needs but also scales as your platform grows. Looking forward to the possibility of discussing this further. Thank you!
$50 USD in 10 days
5.3
5.3

Hi, thanks for your invitation. I have strong experience in blockchain worlds. I am very familiar with solidity and web3, and full-stack web development as well. I look forward to working with you. Best Regards.
$30 USD in 40 days
5.5
5.5

Hi, As per my understanding: You are developing Pet360, a blockchain-powered SaaS platform for Brazil’s pet ecosystem where pet medical records, vaccine certificates, adoption agreements, and insurance processes are securely managed through NFTs and smart contracts. The goal is to build a scalable and reliable ecosystem with strong long-term growth potential. Implementation approach: I can contribute as a blockchain/full-stack developer by building secure smart contracts, scalable backend APIs, and responsive frontend modules for NFT passports, vaccine verification, adoption workflows, and insurance management. My approach focuses on clean architecture, security, performance optimization, and seamless user experience while maintaining smooth collaboration in a remote development environment. I am also comfortable committing 30+ hours weekly for long-term collaboration. A few quick questions: 1. Which blockchain network and wallet integrations are you planning to use? 2. Is the current platform already live or still in the MVP phase? 3. Do you have existing designs and technical documentation prepared? 4. Which module is the highest priority for the next development sprint?
$25 USD in 40 days
5.3
5.3

Hello, I am excited to help build Pet360's Polygon blockchain features including pet NFT passports, vaccine certificate NFTs, smart contract adoptions, and on-chain insurance. I have hands-on experience with Solidity, Polygon, ERC-721/ERC-1155 standards, and secure smart contract development and testing. I can work remotely more than 30 hours per week on a contract basis and am comfortable with a rate in the $20–$60 per hour range. Thank you for considering my proposal; I look forward to speaking with you soon — Sherman.
$38 USD in 40 days
5.2
5.2

Hello, I understand you are building Pet360 as a Polygon-based SaaS platform for Brazil, integrating pet NFT passports, vaccine certificate NFTs, smart contract adoptions, and on-chain pet insurance to create a scalable blockchain pet ecosystem. The focus on real-world medical data immutability and adoption flows requires a secure and well-structured blockchain architecture. I will build Polygon smart contracts (ERC-721/1155) for pet passports and certificates, including minting, transfer, and verification logic. I will develop a NestJS backend for NFT lifecycle management, integrate IPFS/Arweave for metadata storage, and connect a secure frontend wallet system. The solution will be optimized for gas efficiency, upgradeability, and production-grade security. I am ready to commit 30+ hours per week and work closely with your team to ensure fast iteration and long-term scalability of the system. You can also view my portfolio here: https://www.freelancer.com/u/Feriver Thanks, Asif
$50 USD in 40 days
5.2
5.2

Hi. thanks for your invitation for your job position. I have rich experience in blockchain and full stack development. Could you share me more detail for this role? Thanks.
$38 USD in 40 days
4.6
4.6

⚠️ If you're not happy, you don’t pay. ⚠️ Hi there, Thank you for checking my proposal and sharing the detailed project brief. I can build your Pet360 SaaS Platform using blockchain technology, ensuring a secure, scalable, and innovative solution for the Brazilian pet ecosystem. I will deliver: • Pet NFT passports for immutable medical history • Vaccine certificate NFTs for authenticity • Smart contract adoptions for streamlined processes • On-chain pet insurance for added security You will also receive: • Comprehensive documentation for seamless understanding I am confident I can execute your vision professionally and efficiently. Looking forward to discussing timeline and next steps. Best regards, Chirag.
$50 USD in 7 days
4.3
4.3

Hello there, we are a team of senior Full Stack developers and we have extensive experience in Blockchain development. Please, send me a message to discuss the work.
$50 USD in 40 days
4.4
4.4

Hi , I am a Full-Stack Developer with rich experience. I have carefully read your requirements and fully understand that Pet360 is building a blockchain-based pet ecosystem on Polygon, including NFT pet passports, vaccine certificate NFTs, smart-contract-powered adoptions, and on-chain insurance workflows. I understand the goal is not only to implement blockchain infrastructure, but to create a scalable SaaS platform with real-world usability, long-term maintainability, and smooth integration between smart contracts, backend services, and frontend applications. I have strong experience working with full-stack architectures and blockchain-integrated systems, including smart contract interaction, Web3 integrations, API/backend development, and scalable SaaS platforms. I’ve worked with React, Node.js, REST APIs, cloud infrastructure, and blockchain-related workflows where reliability, security, and data consistency are critical. I’m also comfortable collaborating in long-term remote teams and contributing across backend, integration, and product architecture discussions. I’m interested in long-term collaboration and can commit significant weekly availability for ongoing development and scaling of the platform. Let’s connect to discuss in more detail. Best,
$30 USD in 40 days
3.9
3.9

Hi, this is Kris from McKinney, Texas, I've reviewed your project requirements and understand that you are looking to integrate Polygon blockchain into the Pet360 SaaS Platform for various features like Pet NFT passports, vaccine certificate NFTs, smart contract adoptions, and pet insurance on-chain. The key challenge here will be ensuring seamless integration of these blockchain functionalities while maintaining the platform's user-friendly interface. My approach would involve working closely with your team to understand the current platform architecture and requirements for the blockchain integration. I would then develop a comprehensive plan for implementing the desired features efficiently and effectively. A few additional questions: Q1: What is the current tech stack being used for the Pet360 SaaS Platform? Q2: Are there any specific security requirements that need to be considered for the blockchain integration? Q3: How soon are you looking to onboard a developer for this project? Best regards, Kris Kramer
$50 USD in 40 days
4.0
4.0

Hello Thanks for invitation, Im a Senior blockchain developer with experience building NFT systems, smart contracts, and full-stack Web3 apps. Pet360 is a strong use case for real-world blockchain adoption. I can design: • Pet NFT passports with secure medical history • Vaccine certificate NFTs • Smart adoption contracts • On-chain insurance logic Focus: scalable architecture, security, gas optimization, production-ready code. Available +35h/week, remote, long-term collaboration oriented.
$38 USD in 40 days
5.4
5.4

Greetings I can surely help you for Polygon Blockchain Integration for Pet360 I am in the IT industry since more than a decade and serve so many clients in building and rebuilding websites, software, and applications I have strong hands-on different cms like webflow, Wordpress, shopify, squarespace, wix and on different programming languages like PHP, Laravel, React, Node.js, HTML, CSS, And I did the migration from HTML to click funnels. I have made so many websites (E-commerce, WordPress, Classified admin, WooCommerce, etc.), bots, softwares, and Mobile applications (Android, IOS, and Huawei Play store) in my entire career. I have strong hands on both the front end and back end. Currently, I am part of the team who are dealing with miscellaneous tasks in dubizzle and Mzad Qatar including design and layouts and they both have more than 1 million users. I believe that you are looking for a web designer and for sure you will get your end desire result with plagiarism-free work and with better quality as I am assuring you this. Package deals can also be done for long-term collaboration as per the client's requirement. Kindly do come on chat so that we can discuss project details further more.
$25 USD in 40 days
3.4
3.4

Hi, Pet360 is one of the more practical blockchain concepts I’ve seen because the use case naturally fits immutable records, ownership transfer, and long-term verification workflows. The strongest parts are: pet identity/passports, medical/vaccine history, adoption traceability, and insurance-related verification logic. I would approach the system with a clean separation between: on-chain verification/state, off-chain application logic, and SaaS operational workflows so the platform remains scalable and usable for non-crypto users. For this kind of architecture, Polygon makes sense because of ecosystem maturity, transaction cost efficiency, and NFT/smart contract support for consumer-scale applications. I have experience with full-stack platforms, scalable backend systems, Web3 integrations, API architecture, frontend/backend workflows, and blockchain-oriented application logic. I’m comfortable working across frontend, backend coordination, platform architecture, and smart-contract-integrated product flows in a long-term collaborative environment.
$35 USD in 40 days
3.2
3.2

Hi there, I read your job and I am fully confident to deliver this work on time with the premium design execution your pioneering blockchain ecosystem deserves. As a senior brand and UI/UX designer, I specialize in translating complex web3 infrastructures into seamless, premium user experiences. I focus on creating clean, high-fidelity interfaces that establish trust, making features like NFT passports and on-chain insurance feel intuitive and emotionally engaging for everyday pet owners. Here is how I can help: -Design a premium UI/UX for the Pet360 SaaS web and mobile platforms -Create a scalable Figma design system for consistent development -Simplify complex web3 user flows like wallet connection and NFT minting -Design intuitive dashboards for medical histories and certificate management I am available for 30+ hours weekly and ready to bring senior-level execution to this long-term project. Let's connect. Best regards, Shameel
$25 USD in 32 days
3.0
3.0

This is very much within my area of experience, and I understand what it takes to execute it properly. The development of a seamless, blockchain-based pet ecosystem with integrated Pet NFT passports and vaccine certificate NFTs demands a clean, professional, and user-friendly platform to ensure smooth adoption and trust across Brazil’s extensive pet population. I specialize in blockchain development, smart contracts, and front-end engineering, tailored to create automated, secure applications that users find intuitive and reliable. You won’t find someone more aligned with what you’re looking for. I’m open to discussing your project further best case, we build something great together. Regards, Lee-Wayde
$27 USD in 14 days
0.5
0.5

Guelph, Canada
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