Senior Full-Stack Developer for Secure Web Platform + IoT Device Integration
Budget: $250 – $750 USD
Project Summary
We need a senior developer or small senior team to build a production-grade web platform connected to ESP32-based devices via secure MQTT. This is not a simple website, not a UI-only task, and not a beginner project. We already have product direction, completed firmware, PCB work in progress, UI screens, and a detailed functional specification. We now need strong execution.
What Must Be Built
• Customer web application: QR flow, guest checkout, login, wallet, top-up, pay-and-start, session success, transaction history, map, support, settings, legal pages.
• Business / fleet system: company wallet, vehicle management, driver/vehicle sub-accounts, assigned budgets, fleet usage, exports.
• Operator dashboard: location-scoped transactions, revenue based on margin rules, daily/weekly/monthly summaries, CSV export, logical session/device visibility.
• Super admin dashboard: global visibility, operator management, user/business management, audit visibility, support oversight, manual wallet adjustments with audit log.
• Backend and infrastructure: secure API, database, RBAC, MQTT integration, device registry, deployment, staging and production environments.
• Device simulator for integration testing before live hardware rollout.
Important Business Rules
• Two personal membership tiers and two business subscription tiers must be supported.
• Bonus credit is applied instantly on eligible top-ups according to active plan rules.
• Personal wallets and business wallets are separate.
• Business admins can create individual sub-accounts for vehicles/drivers using username + password.
• Each sub-account is limited to its assigned vehicle, budget, and own transaction history.
• Operators must only see their own scoped data and their own margin-based revenue view.
• Super admin must be able to configure global rules, create/block users, create/block operators, and adjust wallet balances with mandatory reason and audit trail.
Device / Integration Facts
• ESP32-based devices communicate through secure MQTT / MQTTS.
• 1 device = 1 bay.
• Per-device pulse mapping is used.
• Heartbeat is available.
• ACK and EXEC are separate states.
• Devices can report executed pulses.
• No physical bay-running confirmation exists in V1; only logical session/device execution status is available.
• OTA remote execution is supported.
• Local device logs exist.
• No real offline local fallback is available in V1 when internet is down.
Required Skills
• React / Next.js or equivalent modern frontend stack.
• Node.js / NestJS / Express or equivalent backend stack.
• PostgreSQL or equivalent relational database.
• MQTT / Mosquitto integration.
• RBAC, secure authentication, audit logs, wallet/payment flows.
• Responsive web apps, admin dashboards, staging/production deployment.
• Strong advantage: prior IoT or embedded-integrated platform experience.
Security Expectations
• HTTPS everywhere.
• Secure authentication and role-based access control.
• Device registry with secure credentials.
• TLS / MQTTS for device communication.
• Safe transaction handling for payment-to-hardware flows.
• Audit logs for critical actions.
• Retry / pending / manual review logic when payment and hardware execution do not fully match.
What To Include In Your Proposal
1. Relevant platform examples with dashboards, payments, or IoT/device integration.
2. Recommended stack for this project.
3. Your experience with MQTT / Mosquitto or similar device communication.
4. How you would handle payment success but hardware failure.
5. Your milestone plan.
6. Your timeline for a production-ready first release.
7. Whether you can deliver development + deployment + device simulator.
8. Post-launch support availability.
Important Notes
• Generic copy-paste proposals will be ignored.
• Please do not bid if you only do frontend, only do design, or have no real backend/integration experience.
• We will share full functional specification with shortlisted candidates only.
We need a senior developer or small senior team to build a production-grade web platform connected to ESP32-based devices via secure MQTT. This is not a simple website, not a UI-only task, and not a beginner project. We already have product direction, completed firmware, PCB work in progress, UI screens, and a detailed functional specification. We now need strong execution.
What Must Be Built
• Customer web application: QR flow, guest checkout, login, wallet, top-up, pay-and-start, session success, transaction history, map, support, settings, legal pages.
• Business / fleet system: company wallet, vehicle management, driver/vehicle sub-accounts, assigned budgets, fleet usage, exports.
• Operator dashboard: location-scoped transactions, revenue based on margin rules, daily/weekly/monthly summaries, CSV export, logical session/device visibility.
• Super admin dashboard: global visibility, operator management, user/business management, audit visibility, support oversight, manual wallet adjustments with audit log.
• Backend and infrastructure: secure API, database, RBAC, MQTT integration, device registry, deployment, staging and production environments.
• Device simulator for integration testing before live hardware rollout.
Important Business Rules
• Two personal membership tiers and two business subscription tiers must be supported.
• Bonus credit is applied instantly on eligible top-ups according to active plan rules.
• Personal wallets and business wallets are separate.
• Business admins can create individual sub-accounts for vehicles/drivers using username + password.
• Each sub-account is limited to its assigned vehicle, budget, and own transaction history.
• Operators must only see their own scoped data and their own margin-based revenue view.
• Super admin must be able to configure global rules, create/block users, create/block operators, and adjust wallet balances with mandatory reason and audit trail.
Device / Integration Facts
• ESP32-based devices communicate through secure MQTT / MQTTS.
• 1 device = 1 bay.
• Per-device pulse mapping is used.
• Heartbeat is available.
• ACK and EXEC are separate states.
• Devices can report executed pulses.
• No physical bay-running confirmation exists in V1; only logical session/device execution status is available.
• OTA remote execution is supported.
• Local device logs exist.
• No real offline local fallback is available in V1 when internet is down.
Required Skills
• React / Next.js or equivalent modern frontend stack.
• Node.js / NestJS / Express or equivalent backend stack.
• PostgreSQL or equivalent relational database.
• MQTT / Mosquitto integration.
• RBAC, secure authentication, audit logs, wallet/payment flows.
• Responsive web apps, admin dashboards, staging/production deployment.
• Strong advantage: prior IoT or embedded-integrated platform experience.
Security Expectations
• HTTPS everywhere.
• Secure authentication and role-based access control.
• Device registry with secure credentials.
• TLS / MQTTS for device communication.
• Safe transaction handling for payment-to-hardware flows.
• Audit logs for critical actions.
• Retry / pending / manual review logic when payment and hardware execution do not fully match.
What To Include In Your Proposal
1. Relevant platform examples with dashboards, payments, or IoT/device integration.
2. Recommended stack for this project.
3. Your experience with MQTT / Mosquitto or similar device communication.
4. How you would handle payment success but hardware failure.
5. Your milestone plan.
6. Your timeline for a production-ready first release.
7. Whether you can deliver development + deployment + device simulator.
8. Post-launch support availability.
Important Notes
• Generic copy-paste proposals will be ignored.
• Please do not bid if you only do frontend, only do design, or have no real backend/integration experience.
• We will share full functional specification with shortlisted candidates only.