Full-Stack Developer for 3PL Platform

DESCRIPTION: We run established e-commerce brands in the Balkans (Shopify, COD-heavy market) and are building our own fulfillment (3PL) software platform. Phase 1 is the client portal for e-commerce brands; phase 2 is the admin/warehouse panel. Why this project is different: you get a complete ~40-page functional specification of the client portal — every screen, field, validation, status workflow, business rule, permission and integration is already documented (shared under NDA with shortlisted candidates). No requirement guessing. SCOPE — CLIENT PORTAL (fully specified): - Multi-tenant architecture (one login → multiple client accounts) - Dashboard with KPIs and deep-linked filtered lists - Users with granular permissions (60 permissions in 13 groups) - Products: staging-based bulk entry (Excel/CSV import, manual entry, e-commerce sync), 90-day stock snapshots, soft delete - Product bundles (virtual SKU → auto-split into warehouse components) - Inbound (receiving) & outbound (dispatch) shipments with status workflows and SLA rules - Orders (core module): staging import, COD/advance amounts, courier assignment, fiscal invoicing, scheduled shipping, advanced multi-filter search, XLSX/PDF exports - Returns/pickups from end customers - Finance: payouts, invoices, analytics - Client settings: pricing tables per courier/route/weight class, service price list, entry defaults, rebate scale - Notifications feed, FAQ module, roadmap page - UI in Serbian (we provide all texts; i18n-ready architecture is a plus) INTEGRATIONS: - E-commerce: Shopify, WooCommerce, Wix (auto-sync every 15 min, two-way stock updates) - Couriers: X Express, D Express (Serbian courier APIs — shipment codes, status tracking) - Accounting/fiscalization: Minimax - Public REST API + signed webhooks (order statuses, shipment codes) TECH: Reference system is an Angular + Angular Material SPA. We are open to your stack proposal (modern SPA + REST API + relational or document DB) — maintainability is the priority. HOW WE'LL WORK: - Phased delivery, fixed-price per milestone preferred; MVP scope is already defined - Markets: Serbia + Bosnia at launch; Montenegro/EU planned — build with multi-country logic in mind - Long-term engagement: this platform is the core of our logistics business TO APPLY, answer briefly: 1. 2–3 similar systems you've built (logistics/ERP/e-commerce backends) — links or descriptions 2. Proposed tech stack and why 3. Team size and roles 4. Rough time + budget estimate for the client-portal MVP 5. Your experience with Shopify API and courier/logistics APIs Start your proposal with the word FULFILLMENT so we know you've read the post.