Full-Stack & Mobile Dev for HOP Logistics

Job Title: Full-Stack & Mobile Development Team / Senior Engineers (Flutter + NestJS + React) for Freight Logistics Platform Project Overview We are building , an end-to-end digital freight matching and logistics platform tailored for the Indian road logistics sector. The system is built around a single backend architecture powering 5 unified client surfaces and driven by a strict, event-driven 14-state trip lifecycle and an automated double-entry escrow ledger. We are hiring experienced freelance engineers, technical leads, or a boutique agency to execute our locked architecture across 15 two-week sprints. Platform Surfaces & Scope of Work You will build five distinct product surfaces operating off a unified modular backend and a shared phone + OTP authentication system: * Driver App (Flutter / Android-first): * Optimized for low-end hardware (sub-3s cold start on 2 GB RAM, APK under 25 MB). * 6-language vernacular localization (English, Hindi, Marathi, Gujarati, Tamil, Telugu) with Text-to-Speech (TTS) voice alerts. * Phone GPS location tracking via background foreground service, offline SQLite ping queuing, backdated pings, and gate geofencing. * In-app trip execution, photo POD capture, and receiver OTP verification. * Fleet App (Flutter / iOS & Android): * Mobile companion for fleet owners/managers to bid, track live fleet maps via WebSockets, and assign drivers/trucks. * Shipper App (Flutter / iOS & Android): * Load posting, live bidding desk, escrow payments, real-time tracking, and receiver OTP delivery flows. * Console (React / Desktop-first Web): * Advanced operations desk for fleet owners and shippers: load board, bidding desk, fleet maps, team seats, invoicing, GST/e-way bills, and ledger exports. * Admin Console (React Web): * Internal ops tool for user/transporter verification, dispute handling, trip manual state control, financial reconciliation, and platform audit logs. Core Backend & System Features * Modular Monolith Architecture: NestJS, PostgreSQL (system of record), Redis (live state, caching, BullMQ queues), and a dedicated WebSocket gateway for live tracking and bids. * Strict State Machine: 14 trip lifecycle states (from DRAFT to CLOSED) driven by append-only event logs with row locks. * Automated Financial Engine: Escrow payment gateway integration (Razorpay Route / Cashfree Easy Split), split payouts, TDS compliance (Sec 194O), and double-entry ledger in integer paise (no raw balance columns). * Real-Time Bidding Engine: Open bidding with timers (10/15/30 min), counter-offers, ranking algorithm, and target push-fanout under 5 seconds. * Return-Load Matching Engine: Rule-based algorithm calculating proximity, route vectoring, and soft-locking loads for approaching trucks within 40 km of drop-off. * Third-Party Adapter Architecture: Clean adapter patterns with fallbacks for Mappls/Google Maps, SMS/WhatsApp (MSG91/Gupshup), KYC/OCR (Sarathi, VAHAN, PAN, GSTIN via Karza/Signzy), E-way bill GSPs, and Call Masking (Exotel). Required Skills & Qualifications * Mobile: Expert-level Flutter & Dart (background services, offline SQLite persistence, battery optimization, complex multilingual UI/fonts). * Frontend: Senior React.js, TypeScript, WebSocket client management, responsive data-dense tables, and dashboards. * Backend: Advanced NestJS (modular monolith design), TypeScript, BullMQ, and event-driven architectures. * Databases & DevOps: PostgreSQL (schema design, row locking, partitioning), Redis, monorepo tooling, Docker, and GitHub Actions CI/CD pipelines. * Fintech & Logistics Experience: Prior experience with escrow gateways, digital ledger systems, GPS tracking systems, or Indian logistics standards (Bilty, e-way bill, VAHAN/Sarathi) is a significant advantage. Engagement Details * Engagement Type: Contract / Freelance (Milestone-based or Dedicated Team per Sprint). * Timeline: 15 two-week sprints (~7 months) to Closed Beta launch. * Deliverables: Production-grade monorepo containing backend, 3 Flutter apps, 2 React web apps, tests, and CI/CD setup.

How to Apply

Please submit your proposal with: * Links to past work, specifically complex Flutter applications, real-time tracking systems, or financial/marketplace platforms. * An overview of whether you are applying as an individual specialist (Backend/Frontend/Mobile) or an integrated development team. * Your availability and preferred engagement model (sprint-based fixed milestone vs. monthly rate).