Corporate project · Industrial manufacturer · In use

Rewriting a Vendor-Locked CRM In-House

A vendor-locked microservice CRM was rewritten in-house. Auth, opportunities, requests, quotes/orders, customers, stock and collections now run in a single .NET 8 API, and six front-end modules were merged into one Next.js app. All code running in production is now the company's own.

Web app
Database / SQL
Integration

2 daysto migrate every service
71 / 0endpoint scan: endpoints / issues
33 / 0page scan: pages / issues
6 → 1front-end modules merged into one app
658git commits
208C# source files
106front-end pages
91SQL migrations

1BrowserOne Next.js app
2Reverse proxyApache, no API gateway
3.NET 8 APIEvery service in one API
4SQL ServerVendor schema + new database
5Nightly backupWatchdog and monitoring

Auth & ticketing
Opportunities & requests
Quotes / orders
Customers
Stock
Collections

Built for an industrial company. For confidentiality, the company name, logo, product/part codes and internal data are not shared; images are cropped accordingly. The architecture diagram is illustrative.

The need

The CRM depended on an outside vendor: the company did not own its code or data, and menus were duplicated.

The solution

Service-by-service migration, each endpoint verified against "golden file" comparisons with the old behaviour.
Vendor schemas were left untouched; new tables live in a separate database.
The API gateway was removed; the reverse proxy routes straight to the new services.
Auth and ticketing were rewritten.
Windows services with a watchdog task, and nightly automatic backups.
The cut-over was fully reversible, step by step.

Delivered

CRM API
Unified front end (6 modules)
Service, backup and monitoring scripts
Cut-over and rollback documents

Technologies

C# / .NET 8
Dapper
SQL Server Express
Next.js 14
React
RTK Query
Formik / Yup
Tailwind
Apache (reverse proxy)
Windows Services
Python (comparison and scan tools)

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