Tanpin

Item-by-item inventory that reorders itself. Per-SKU demand forecasts, automatic purchase orders, supplier email and delivery ETAs — with a REST API, an MCP server, a daemon, and a dashboard. Pure Node 22, zero runtime dependencies (node:* built-ins only).

Live demo: huggingface.co/spaces/willykeenan/tanpin (read-only, seeded sample data)

_{Real screenshot of the demo; the data in it is invented sample data.}

Per-SKU forecast with weekday and trend factors, safety stock, reorder point and a manager hypothesis.

Purchase orders the cycle raised, grouped by supplier.

Why tanpin kanri

Tanpin kanri (単品管理, “single-item management”) treats every SKU as its own business. A store manager forms a hypothesis about tomorrow’s demand for that item — weather, a local event, day of week — orders against it, then verifies the result against actual sales. High-velocity items get tight control and frequent replenishment. The long tail gets simpler rules, and is the first to be delisted.

Tanpin encodes that loop in software:

1. Forecast each SKU from recent sales, weekday seasonality, short-term trend, and manager-entered hypotheses (events, weather, promotions).
2. Compute the order — safety stock at a chosen service level, reorder point, EOQ, pack-size rounding, minimum order quantity, and a JIT cap on days of supply.
3. Buy and track — purchase orders grouped by supplier, emailed automatically, with a delivery ETA from lead time, cut-off hour, and delivery windows.
4. Stop stocking what does not sell — dead and slow SKUs are flagged to delist.

ABC classification follows the same idea: a small set of A items drives most value and gets the freshest reorder cadence; C items are the delist pool.

Features

• Per-SKU forecasting — recency-weighted moving average, day-of-week factors, trend (±40%), compounding hypotheses
• Automatic reorder — safety stock, reorder point, EOQ, pack size, MOQ, max days of supply
• ABC + delist — A/B/C by revenue contribution; dead (no demand) and slow (too many days of supply) flags
• Daemon — every N minutes (default 15): re-forecast, reclassify, raise draft POs, optionally email and auto-receive
• Supplier email — SMTP over implicit TLS (port 465) when SMTP_HOST is set; otherwise .eml files in the outbox
• Delivery ETAs — lead time snapped to the next delivery window, honoring cut-off hours (UTC today)
• REST API — products addressed by SKU, OpenAPI 3.1 at /openapi.json, agent guide at /llms.txt
• MCP server — newline-delimited JSON-RPC over stdio for Claude Code, Codex, Cursor, and any MCP client
• Dashboard — vanilla JS SPA at / (products, orders, suppliers, forecast, activity, API, settings)
• Webhooks — HMAC-SHA256 signed JSON POSTs (X-Inventory-Signature)
• CSV — import/export products; export the movement audit trail
• API keys — stored as SHA-256 hashes, full key shown once
• Idempotency-Key — 24h replay window on sales and purchase-order writes
• Plugins — TANPIN_PLUGIN loads extra HTTP routes and usage limits
• Storage — SQLite (node:sqlite, WAL, incremental row writes; data/inventory.sqlite) shared safely by the server and a standalone daemon; JSON fallback with TANPIN_STORE=json

60-second quickstart

Requires Node.js 22 or newer.

npx github:willykeenan/tanpin serve

Open [http://localhost:4173](http://localh

... View full README on GitHub