I built an open-source WMS because every warehouse management system costs $2,000/month

#opensource #python #docker #react

Every WMS on the market is either a six-figure enterprise implementation, a $500-3,000/month SaaS with workflows you can't change, or an ERP bolt-on that was never designed for a warehouse floor. There has never been a credible open-source alternative built for e-commerce fulfillment. Today that changes.

I'm a warehouse manager at an e-commerce company. 8,000 orders/month, 5 scanning stations, and I function as the entire technology department. I needed a WMS that didn't force my team into someone else's workflow. Nothing existed that fit, so I built one.

What Sentry WMS does

Full warehouse lifecycle, all scan-driven:

Receiving : scan PO, scan items, track quantity, complete
Put-Away : scrollable list, scan any item in any order, scan destination bin
Pick Walk : item counter, next preview, optimized path
Pack Verification : scan SO, scan items to verify, confirmed rows
Shipping : carrier picker, tracking entry, completion
Cycle Count : blind/non-blind, pending records, admin per-bin approve/reject
Bin-to-Bin Transfer
Admin Panel : inventory, items, POs, SOs, users, warehouses, settings, import, audit log

Stack

Python/Flask API with parameterized SQL and service layer
React 18 + Vite admin panel
React Native (Expo) mobile app with broadcast intent scanner support
PostgreSQL 16
Docker Compose (one command to run the entire stack)

Security

I ran two independent security audits using Claude Opus and Sonnet in separate sessions. Opus identified vulnerabilities that were low-risk independently but dangerous once chained together. 18 vulnerabilities found and fixed total.

Parameterized SQL on every query, warehouse authorization middleware on all endpoints, random admin password on first run, live DB validation on every authenticated request, login lockout, non-root container with gunicorn, security headers, and CORS restricted to configured origins.

Hardware testing

This wasn't built in a browser. I test on a Chainway C6000 industrial barcode scanner running Android 10. The mobile app uses broadcast intents (com.chainway.sdk.barcode.BARCODE_DECODING_DATA), not keyboard wedge, not camera scan. Real warehouse hardware.

The standalone APK is attached to the GitHub release.

Get running in one command

git clone https://github.com/hightower-systems/sentry-wms.git
cd sentry-wms
docker compose up -d

Admin panel at http://localhost:3000. Admin password is randomly generated on first run, check docker compose logs for credentials. Demo data included so you can explore immediately.

For production (no demo data):

SKIP_SEED=true docker compose up -d

What's next

v1.1: Input validation schemas, Redis rate limiting, error boundaries, MkDocs documentation site
v2.0: ERP connector framework; NetSuite, Shopify, BigCommerce
Sentry Cloud: Hosted SaaS for teams that don't want to self-host

Sentry is the warehouse execution layer. Your ERP stays the system of record.