The API is structured across dedicated layers — Core (Features + Services), Models, Database, and API — with a separate ReCalc engine project. The Core layer organizes business logic into feature modules (Account, Order, Inventory, Grower, Conditioner, AR, Wholesale, and more), each handling its own queries, commands, and service interactions. A separate SalesPortal.Api serves ISR field users with a dedicated, lightweight API surface for order entry and account lookup — independently deployable from the main StinePortal.Api. Serilog writes to a dedicated Azure SQL log database isolated from operational data.

The CRM module is the commercial core of the portal. Dealer accounts are managed through a multi-step workflow covering account details, company year assignments, DSM/RSM territory assignments, acreage data, ownership, contact information, trait provider licenses, and zone codes. Each account's full order history is accessible from the account view. The prospect pipeline gives ISRs a full workflow — importing prospects from external files, assigning them, logging weekly visits and ISR visit tracking, and progressing them through status stages. A CRM dashboard provides ISRs and managers with a live summary of accounts, visits, and prospect pipeline health.

The ordering module supports two distinct placement flows — ordering by product (browsing the full product catalog and allocating quantities per account) and ordering by conditioner (placing orders against a specific conditioner's available inventory). Orders are structured as header/detail records with per-line product, quantity, and pricing data. Shipment management covers shipping requests, Bill of Lading generation (in multiple formats including detail, YTD, and inventory-by-lot), return shipments, transfer shipments, and post-shipment reporting. Every order and shipment carries a full audit trail of who acted, when, and against which company year.

A standalone StinePortal.Core.ReCalc project handles Stine's multi-layer pricing recalculation. Customer-level prices are computed by applying a defined sequence of discount rules — volume discounts, region discounts, JD discounts, special pricing programs, dealer price adjustments, and tech fees — against base prices, then reconciling payment credits and shipment adjustments. The ReCalc engine regenerates GL entries for affected orders and produces the Recalculate GL Print report used by Stine's finance team at the end of each pricing cycle. This faithfully replicates the business logic of the legacy AS/400 pricing recalculation system in a testable, maintainable C# architecture.

A full AR module manages Stine's dealer receivables lifecycle. Account statements are generated per dealer showing open balances, payments, and aging. The Aged Trial Balance report surfaces outstanding receivables by aging bucket across the dealer network. Open invoice management tracks individual invoices, payment applications, and outstanding balances. Late charge calculation and application follows configurable rules. Payment recording covers cash receipts, credit memos, and adjustments. GL entries are generated for all financial transactions and exportable for Stine's accounting team. All AR reports are produced as formatted PDFs via QuestPDF.

The Production module manages Stine's supply chain from the seed variety level down to physical inventory at conditioners and elevators. Grower contracts cover agreements, trait provider licenses, location assignments, pricing, premium liability, and production estimates. Conditioner profiles manage agreements, contacts, location assignments, package type authorizations, and max volume reporting per company year. Inventory is tracked across multiple physical types — bagged, bulk, delivered at plant, and elevator — each with its own lifecycle, notes, germination scores, seed sample records, trait test results, and bin codes. The Bagging Approval workflow authorizes seed lots for bagging with approval stages and quality scoring.

A dedicated wholesale module manages Stine's wholesale seed transactions independently from the dealer ordering system. Wholesale shipments are created, tracked, and invoiced with per-shipment payment recording and payment reporting. Wholesale term files define the pricing and payment terms applicable to wholesale accounts. Wholesale transaction history is maintained with full auditability. All wholesale documents — shipment invoices, payment confirmations, and purchase statement reports — are generated as structured PDFs via QuestPDF, maintaining the output format that Stine's wholesale customers expect.

The platform generates over 80 distinct structured PDF reports using QuestPDF — covering every operational domain. Key report types include: Bill of Lading (detail, YTD, by BL type, inventory by lot, worksheet), Order reports (order status, order summary, orders vs supply, orders by RSM/DSM/product), Inventory reports (bagged summary, available corn/soybean, inventory valuation, conditioner available inventory), Grower reports (grower contract, settlement, premium liability, production estimates, pricing), AR reports (aged trial balance, account statement, late charge, GL entries, open invoices), Conditioner reports (contract, account summary, conditioner settlement), Shipment reports (shipment, shipping request, post-shipment), Wholesale reports (purchase statement, shipment invoice, payment). Each report faithfully reproduces the output format of the legacy AS/400 reports Stine's staff relied on.

All dealer, grower, conditioner, and contact addresses are validated against the USPS Address Validation API at the point of entry, ensuring deliverable addresses for mailing labels, shipping requests, and printed documents. A Census service integration resolves geographic boundary data (FIPS codes, state/county/township) for Stine's territory and region management. These integrations ensure that physical address data throughout the platform is accurate, standardized, and usable for Stine's field operations and financial mailings.

The Business Feature system allows Stine's operations team to enable or disable specific platform capabilities per company year through the admin portal — with no code changes required. Features are defined as named platform capabilities; each company year activates a range of features controlled by CompanyYearRange records. Access control is implemented as a multi-layer permission model: role-level permissions gate modules and actions; individual users can receive permission overrides beyond their role; job assignments scope ISRs, DSMs, and RSMs to their territory and account data. All permission rules are enforced consistently at Angular route guard level and API authorization middleware simultaneously.