Senior Full-Stack Webapp + IoT / Device Integration Developer or Small Senior Team -- 3

@webbookstudio

Hi there, We understand you're looking for a senior full-stack developer or a small senior team to build the SFD platform, a production-ready webapp for self-service car wash and related vehicle service locations, including payments, wallet/credit logic, role-based admin dashboards, and integration with ESP32-based field devices. At Webbook Studio, we have relevant experience in building complex web applications, including a learning platform website with custom PHP and WordPress development, and an e-commerce site for a Scandinavian fashion brand using WooCommerce and custom design. Our team is skilled in React, Node.js, PostgreSQL, and MQTT, which aligns with your project requirements. We've also worked on projects that require secure payments, role-based permissions, and database integrity. We will deliver a complete responsive webapp for customer, fleet, operator, staff, and internal admin roles, along with a backend API and database, payment integration, wallet/ledger logic, and device registry. Can you please share more details about your expected timeline and how you envision the role-based permissions and audit logging being implemented? Feel free to message us to discuss the details! — Webbook Studio

@DeveloperStation

Hi there, We’ve built multiple production-ready web apps with complex backends and IoT integrations, including a fully functional car wash solution that connects with devices via MQTT and handles payments, subscriptions, and user roles. We can deliver a robust, scalable product with a strong focus on security and performance. We also provide a dedicated QA resource to ensure everything works perfectly before launch. Let’s schedule a 10-minute introductory call to discuss your project in more detail and see if I’m the right fit for your needs. I’m looking forward to hearing more about this exciting project. Best, Adil

@SBITServices

Hi, I will develop a production-ready web application for a self-service car wash and related vehicle service locations, integrating secure payments, role-based admin dashboards, and communication with ESP32-based field devices. My solution will include customer webapp, business/fleet system, fleet driver mobile flow, operator admin dashboard, backend infrastructure, device simulator, and integration testing. Let's discuss further. Start the chat to discuss in detail. Regards, Sai Bhaskar

@melikatfz

Hi there, diving into your project needs, I spot a crucial point many might overlook: integrating MQTT for ESP32 devices while ensuring secure payment flows. I excel at backend architecture, delivering intricate systems that ensure data integrity and seamless device communication. My previous project involved building a scalable platform with a 99.9% uptime, handling complex payment and role-based admin features effectively. I include 30 days of post-deployment bug-fixing, ensuring a smooth launch. What specific MQTT features are prioritized for your device communication? Let's discuss how I can bring this to life.

@kishanbwts

I’ve built full-stack platforms with complex payment and wallet ledgers, role-based access, and secure device integrations before. For your SFD platform, I’d start by mapping your specified roles and permissions strictly in the backend and frontend to prevent data leaks across companies, operators, and drivers. Regarding hardware execution uncertainty after payment confirmation, I suggest implementing a robust retry and transaction state machine with clear statuses—leveraging MQTT ACK and EXEC states to ensure commands are confirmed before finalizing any wallet debit or service completion. To track every financial transaction, I would design a ledger with immutable transaction references linked to payments, wallet credits, support tickets, and audit logs, all secured by role-based access controls. For device communication, I have experience building MQTT gateways with secure TLS and device simulators that test offline, degraded, and failure scenarios before rollout. Do you have a preferred payment provider, or should I recommend one with strong webhook and sandbox support? Also, will the staging environment use separate hardware simulators to fully replicate device states ahead of production? I can deliver the full stack, deployment pipelines, monitoring, backups, device simulator, and about 30 days of post-launch support. Ready to review the specs and start building a stable, secure production system.

@Eliteinno

Hi there, Building a robust, production-ready platform for a self-service car wash with seamless payment integration and device communication can be challenging. Ensuring secure backend architecture, reliable device interaction, and role-based permissions are critical for success. At Eliteinno, we excel in delivering complex web applications with secure payment systems and IoT integrations. Here are our questions: 1. Which payment provider are you planning to use for this platform? 2. Do you have a preference for specific cloud services for deployment and monitoring? Having successfully completed similar IoT-enabled projects with secure payment systems and rigorous role-based access controls, we are confident in our ability to deliver this project. We invite you to review our portfolio and can share relevant samples in chat. Plus, we offer 30 days of free support post-launch to ensure a smooth transition. Let’s discuss your project today!

@abhishek060

Hi, I’m a senior full-stack developer focused on building production-grade systems with complex workflows, payments, role-based access control, and reliable backend architecture. Your SFD platform aligns closely with the type of systems I specialize in—multi-role dashboards, wallet/ledger-based financial logic, and real-time device integrations where consistency and security are critical. I have experience designing scalable backend systems with: • Secure RBAC and multi-tenant architecture • Payment integrations with webhook handling, idempotency, and reconciliation • Ledger-based wallet systems ensuring financial accuracy • API-first architectures with clean separation of services • Event-driven workflows and state management across distributed systems For this project, I would approach it with a modular architecture using a strong backend core (Node/NestJS + PostgreSQL), strict permission enforcement at API level, and a fully traceable transaction + device execution workflow from payment → wallet → service → audit log. I also ensure production readiness from day one, including testing strategy, staging environments, monitoring, and safe deployment pipelines. I’m comfortable working from detailed specifications and translating them into a stable, scalable system that can safely handle real-world transactions and device interactions. Ready to start immediately. Abhishek

@Dzimark

Hello, Main risk is device-state reconciliation and payment execution atomicity: ensuring MQTT device commands, backend wallet ledger entries, and payment gateway confirmations remain consistent under network partitions and device offline scenarios. I lead Dzimark, a full-service team that has delivered 100+ production web and mobile platforms including fleet, payment, and IoT integrations. We have built Node.js/NestJS backends, PostgreSQL ledgers, React frontends, MQTT device gateways and operator dashboards in production for vehicle-service and kiosk-like systems. I will start with a short system-design spike: canonical event flow for user payment -> wallet ledger entry -> device command via MQTT and compensating rollback paths for failures. That spike will produce sequence diagrams and a minimal proof-of-concept that demonstrates ledger atomicity and device ack handling. - relevant examples of production platforms We have multiple fleet and service platforms combining React frontends, Node/NestJS backends, PostgreSQL wallets, and MQTT gateways. Detailed case references available after NDA. - recommended technical stack Frontend: React (TypeScript). Backend: Node.js with NestJS. DB: PostgreSQL with row-level ledger tables and event log. MQTT broker: EMQX or Mosquitto behind TLS. Payments: PCI-compliant gateway (Stripe/Adyen) with webhooks. Auth: JWT + RBAC via database-enforced roles. - experience with MQTT/IoT Implemented MQTT brokers, retained messages for offline devices, last-will handling, per-device TLS certs, and gateway services translating MQTT to backend events. - handling payment execution failures Use two-step: authorize then capture, create pending wallet transaction, mark commands as conditional; on capture failure send compensating cancel and credit reversal with audit trail. - wallet ledger implementation Immutable transaction table, balance snapshot per account, idempotent transaction tokens, and reconciliation jobs. - role permissions enforcement DB-enforced RBAC with row-level security for fleet/operator/super-admin and API middleware checks. - proposed milestones Week 0 spike; Weeks 1-3 API, wallet, auth; Weeks 4-6 device gateway and MQTT flows; Weeks 7-9 frontends and dashboards; Week 10 QA and deployment. - post-launch support availability Providing 3 months of SLAs for bug fixes, monitoring, and hotpatches; longer-term retainers optional. - Would you like the NDA now so I can share specific case references and an architecture spike within 3 business days? - Which payment gateways and existing device hardware/protocols do you currently use? A quick call works for me whenever you are ready. Dzimark

@mughiraaa

Hello, I would like to request a discussion meeting regarding the SFD platform project. I have strong experience working on full stack systems that combine payments, role based access control, transactional ledgers, and real time device communication. My background includes backend architecture design, API driven systems, and platforms where financial accuracy and audit traceability are critical. In our meeting, I can walk through how I would structure the system across customer, fleet, operator, and admin layers while keeping strict separation of permissions and wallet logic. I can also explain my approach to ledger based transactions, webhook safety, idempotency handling, and secure payment confirmation flows so that no duplicate charges or invalid device triggers occur. On the IoT side, I have experience working with event driven communication patterns and can outline how MQTT based device messaging, ACK and EXEC states, and offline handling would be managed safely with simulation testing before hardware rollout. I would also be glad to explain how transaction references would connect payments, sessions, device actions, and support workflows for full traceability. I would appreciate the opportunity to align on architecture, milestones, and delivery expectations so we can move toward a stable production ready release with confidence. I will share my portfolio in chat I look forward to hear from you. Thanks Best Regards, Mughira

@asimaarbi

Hi, This is the kind of system I enjoy working on—complex, real-world platforms with multiple user roles, payments, device integration, and operational workflows. I have 5+ years of experience building scalable web and mobile applications, including backend APIs, payment integrations, role-based access control, admin dashboards, and IoT-connected solutions. I've also worked extensively with ESP32-connected systems and real-time communication using a WAMP-based architecture, enabling reliable communication between devices, backend services, web dashboards, and mobile applications. Additionally, I have already built mobile applications for a car wash management system and can demonstrate them during our discussion. This gives me practical experience with customer flows, operator workflows, QR-based processes, payments, and device-driven operations. Your requirements around wallet management, ledger integrity, QR workflows, fleet management, operator portals, device communication, and reporting are areas where I can contribute immediately. I'd be happy to review the full specifications and discuss the architecture and implementation approach. Best regards, Asim Farooq

@MIndlabsAi6

Hey there, I'm Vishal Maharaj, a seasoned Software Architect with 25 years of experience in technologies like PostgreSQL, React.js, Node.js, and API Integration. Based in Perth, Australia, I'm passionate about taking on your project. I understand the complexity of building a production-ready webapp for self-service car wash and IoT integration. My approach involves creating a robust backend architecture, secure payments, role-based permissions, and seamless device communication. Let's discuss further details and kick start this project. Feel free to initiate the chat. Cheers, Vishal Maharaj

@mugencodes

Hello, Are you seeking a senior full-stack developer or a small senior team to build a robust webapp for self-service car wash and vehicle service locations, including IoT integration with ESP32-based devices? Look no further. With expertise in Software Architecture, Node.js, React.js, PostgreSQL, and API Integration, I am well-equipped to handle the complexities of this project. I understand the importance of secure payments, backend architecture, and database management in creating a production-ready platform. My experience in developing customer webapps, business/fleet systems, and operator admin dashboards aligns perfectly with your requirements. By leveraging my skills in React.js, Node.js, and MQTT, I will ensure seamless device communication and integration. Additionally, my proficiency in database management and API integration will guarantee a smooth deployment process. I am confident in my ability to deliver a high-quality solution that meets your expectations. Let's discuss how I can bring your vision to life. Best regards, Jayabrata Bhaduri

@himanshus642

With over 5 years of experience as a full-stack developer, I bring a wide range of skills and knowledge to the table. My specialization in SaaS platforms, AI automation, fintech systems and API integrations make me a perfect fit for your project involving self-service car washes and IoT/device integration. I understand the complexity involved in building a robust platform like the one you require, including secure payments, role-based permissions, database integrity and device communication. I have a proven history of automating and streamlining manual operations, which will be invaluable in your project that involves integrating payment, wallet and fulfilment processes seamlessly. Drawing on my deep understanding of API-driven architectures and my knowledge of SQL and NoSQL databases, I can build a rock-solid backend that facilitates all the functionalities required from QR-based service flows to billing-related actions. Moreover, as someone who has worked extensively with cloud technologies like AWS and CI/CD practices, I understand the significance of deployment and QA discipline for production-ready applications. My meticulous attention to detail ensures that I adhere to specifications without fail while keeping long-term scalability in mind. My goal is always to deliver more than expected; so let’s discuss how we can make your vision for the SFD platform even better!

@rakeshkumar1684

Hi, Your SFD platform requires much more than a standard web application—it needs secure financial workflows, strict role-based access, payment reliability, IoT integration, and production-grade infrastructure. I can deliver the complete solution from architecture through deployment and post-launch support. I have experience building dashboard-driven platforms, payment integrations, role-based systems, API-driven applications, and workflow automation solutions. My approach would be to implement a secure ledger-based wallet system with immutable transaction records, audit logs, and unique Transaction References linking payments, wallet activity, sessions, support cases, and settlements. For hardware reliability, payment confirmation and device execution will be separated using a state-machine workflow. ACK confirms command receipt, EXEC confirms execution status, while retries, idempotency keys, timeout handling, and manual review workflows prevent duplicate charges, wallet debits, refunds, or device commands. If payment succeeds but execution remains uncertain, credits can be safely reserved and released or refunded according to business rules. I can deliver the complete web application, backend APIs, payment integration, wallet system, device registry, MQTT gateway, device simulator, deployment environments, monitoring, documentation, testing, and post-launch support. Estimated timeline for a production-ready V1 is 14–18 weeks after final specification review.

@Anika1802

With my extensive experience in building SaaS platforms, working with APIs, and developing integrated applications, I believe I'm the perfect fit for your project. I've successfully built over 40 web and mobile applications from scratch, ensuring high-performing, reliable, and scalable solutions. For your specific project, I'll work proactively to create a production-ready webapp that addresses every granular detail of your functional specifications. Another valuable asset I bring to the table is my capability to design, build, automate and maintain a full-stack end-to-end solution that aligns with every aspect of your project needs. From UI/UX design to frontend development to backend architecture to automation, deployment, optimization - rest assured that I cover it all. Plus, as an avid communicator with a keen eye for details, I will ensure there aren't any gaps when implementing your architectural designs or engaging with MQTT/MQTTS or HTTP-based device communications. My ultimate goal is to contribute towards creating an app that fulfills your vision accurately while helping your business exponentially scale up.

@Tarang78

Hi! I’m Tarang, I have over 12 years of experience and have previously completed a ull-Stack Webapp project. I am really interested in this job. I’m ready to start immediately and can deliver high-quality work within your timeline. Please join the chat so we can discuss and start immediately.