Backend + Web for the Power Bank rental service through charging stations (QR / IoT)

Good day.
I have experience in backend / full-stack development of services with payments and complex business logic. I can implement the backend for rentals (sessions, rates, payments), integration with stations (IoT / API), web flow after QR, and an admin panel for managing the service.

I work with an MVP approach, laying the architecture for scaling.
I am ready to discuss the stack, integrations, and implementation stages.

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Hello,

My name is Gor Abrahamyan, and I am a web developer with experience in building e-commerce solutions and custom web systems. I am very interested in your auto parts store project and would be glad to help you implement it efficiently and reliably.

I specialize in developing online stores with:

Product catalogs and category management

Search and filtering for auto parts
…
Shopping cart and checkout systems

Payment and delivery integration

Admin panels for easy content and order management

Responsive design for mobile and desktop

I focus on clean code, performance, and scalability, ensuring that the store is fast, secure, and easy to maintain. I can work with existing designs or create the project from scratch based on your requirements.

I would be happy to discuss your goals, technical needs, and timeline in more detail.

Thank you for your time, and I look forward to your response.

Best regards,
Gor Abrahamyan

super interesting project!

I am interested in collaboration!

I have 6 years of experience in IT development. I can handle the backend part.

Let's discuss the terms in private messages?

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Good day!
My name is Valentin, and I represent Arctic Web Agency. We are a team of experienced web developers who specialize in creating modern and effective web solutions for businesses. I can provide examples of our similar work in personal messages. We are ready to take your project to work!

Sincerely,
Arctic Web Team
Freelancehunt

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We specialize in similar panels and have extensive experience working with IoT devices. I am ready to take on your project.

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super happy to help you out with this
will share previous work in chat to make sure we match together

Hello, Kyrylo! I have thoroughly reviewed your technical specification (draft). The task is clear: building a Backend core for sharing power banks, integrating with IoT protocols of stations, and a Web interface for clients/admins.

Answers to your questions (item 11):

Stack (Backend + Web): — Backend: Node.js (NestJS). Why: perfect support for TypeScript, modularity, easy handling of WebSockets/MQTT (for real-time communication with stations) and RabbitMQ queues (for reliability of "issue/receive" commands). — Database: PostgreSQL (for reliable transactions/rentals) + Redis (for caching slot statuses). — Frontend (Web-flow + Admin): Next.js. This will ensure instant loading of the rental page after scanning the QR code (SSR).

Experience with IoT/Payments: I have experience working with WebSockets (NestJS Gateway) and RabbitMQ for asynchronous event processing. I have implemented payment integrations (Stripe) via Webhooks.

3. Offline Logic and Event Log: — I will use a message queue (RabbitMQ). If the station is Offline, the command does not get lost but waits in the queue (with TTL). — Upon restoring the connection, the station sends a package of accumulated events (bulk update). The backend compares the timestamps of events and updates the status of slots in the database. — Logging all "raw" requests from stations in MongoDB (as cold storage) for auditing disputed situations.

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Welcome!
The Spectrium team is ready to undertake the implementation of the power bank rental service according to the technical specifications.

What we offer:
• Backend with complete rental logic: users, sessions, tariffs, payments, fines
• Integration with stations (HTTP / MQTT / WebSocket — depending on the manufacturer's protocol)
• Web-flow after QR (start of rental, payment, status)
• Admin panel: stations, rentals, tariffs, users, dashboard
• Event logs and proper operation during offline stations
…
Experience:
• IoT / hardware integrations
• Payment systems
• Backend for services with real-time events and finances

Stack (proposal):
Backend — Node.js (NestJS) or Laravel
DB — PostgreSQL + Redis
Web / Admin — React / Next.js
API documentation — Swagger

Format:
• Implementation in stages (MVP → stabilization)
• Payment by sprints
• Long-term cooperation

We are ready to discuss the station protocol, payment model, and provide an estimate by stages after a brief technical round.

Spectrium

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Hello,

Thank you for the detailed description, I would be happy to help with the implementation of the project. I am a Software Development Engineer with more than 7 years of experience in creating various websites, SaaS solutions, complex web platforms, and MVPs for startups. In my portfolio, I have highlighted some developed projects.

My stack includes the following technologies and their frameworks: PHP (Yii2, Laravel, Symfony), HTML5, CSS3, JS (Vue.js, React.js), MySQL, PostgreSQL.

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Good day. I am ready to complete this project as I have extensive experience in application development.

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Hello!

This is a reliable and well-thought-out product, and I confidently create systems where the equipment, payments, and backend logic must remain stable even in real-world conditions. I have worked on rental platforms with session-based logic, deposits, penalties, and complete audit logs, and I understand how important trust and traceability are when it comes to money and devices.

I can design a backend-oriented architecture that clearly separates users, rentals, rates, payments, and station status, while ensuring the resilience of the integration with the station to weak or lost connections. Working with device protocols, message queues, retries, and state reconciliation after periods of disconnection is something I have already encountered, including detailed event logs that can be reproduced for dispute resolution.

One idea I would propose is an immutable event timeline for each rental session that records every station signal, payment action, and system decision. Even if the station disconnects, the system will be able to safely restore the final state later without guesswork, which is critically important for scalability and customer support.

To create a minimum viable product (MVP) with subsequent stabilization, integration with the admin panel and stations, I would estimate a timeline of about 45 days with a budget of $5000.
…
Thank you!

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Hello, nice to meet you.
I have carefully reviewed your requirements.
Regarding the technology stack, I think that React.js + Node.js would be well suited for your project.

I have sufficient experience in banking and card integration and can successfully complete your project within one month.
Let's discuss this in more detail.
Best wishes.

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Hello! I am ready to write the backend for the Power Bank rental. I suggest using the Laravel stack. I can also implement the frontend, as I work as a full stack developer. I will complete your task quickly and efficiently.

My portfolio: https://freelancehunt.com/ua/freelancer/romas6ka.html#portfolio
Write to me, I will start working today. I will be happy to collaborate with you!

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I developed rental and billing systems linked to hardware/devices (statuses, sessions, payments). For the power bank service, I immediately see the key components: rental as a session, timing control, returns, station failures. I can implement the backend + web (QR page, admin panel), starting with architecture and MVP. The MVP will take a week.

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Dear Kyrylo!
I have reviewed your technical requirements for the portable external battery rental service with a user interface and integration with Internet of Things stations. Based on 8 years of experience in creating scalable web and Internet of Things platforms, I propose the following solution:

Technical Solution
Stack: MERN (MongoDB, Express.js, React, Node.js) for full-stack development. This allows for rapid development of a responsive web interface, a reliable REST/GraphQL API backend, and flexible data modeling for dynamic entities such as users, stations, slots, and rentals. MongoDB provides a scalable storage solution for events, logs, and transactions, including offline synchronization with stations.

User Interface: Station access based on QR codes, web authorization (phone/SMS or email), card payment with deposit/penalty logic, and session management.

Backend and API: Node.js/Express backend with JWT-based authentication, role-based access for admin/users, complete audit logging, and rate/payment calculation logic. RESTful API (documented with OpenAPI/Swagger) for integration with stations and the web interface.
…
Integration with Internet of Things: Communication with the station is done via HTTP API/MQTT/WebSocket depending on the manufacturer. Includes commands for issuing/accepting/heartbeat/status, reliable error handling, and offline event recovery with subsequent consistency.

Payments: Integration with a payment service provider that supports card transactions, deposits, and refunds. Designed for future expansion to NFC or alternative methods.

Admin Panel: Web panel based on React for monitoring stations, rentals, user management, rates, and financial reporting with real-time updates.

Non-functional requirements: Security through JWT/session management, rate limiting, admin protection, audit logs.

Scalable architecture to support over 100 stations. Reliable operation with robust event logging and recovery mechanisms.

I am confident in creating a stable platform with clear documentation, deployment instructions, and automated checks for critical business flows.

I would be happy to discuss in detail the choice of stack, Internet of Things integration strategies, and approaches to offline synchronization.

Best regards,

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Hello. I have been working with React/Node.js for over 8+ years. I am ready to implement the project.

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Hello.

I am a NodeJS developer. I am ready to take on the task. Write to me, we will discuss.

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