Your webshop, marketplaces, ERP, accounting and carriers should talk to each other, so nobody types the same order twice. I build integration services in C#/.NET that keep orders, stock, invoices and shipments in sync, with background jobs, retries and error logging so failures are visible instead of silent.

Delivered examples: real-time sync between Trendyol, Hepsiburada, N11 and Netsis accounting with e-invoices and e-waybills, and a PrestaShop pipeline to accounting and four carriers.

Packages (fixed price, USD):

Starter — $600, 5 days (about 8 hours of work): Review of your systems and APIs, field mapping and a written integration plan, or one simple one-way sync for a single entity (for example orders) where the APIs are documented.

Standard — $1,800, 14 days (about 24 hours of work): A two-way integration between two systems (for example webshop and ERP/accounting): orders, stock and invoices, scheduled background jobs, retries, error logging and deployment notes.

Advanced — $4,500, 30 days (about 60 hours of work): An integration service connecting several systems (marketplaces or webshop, ERP/accounting, carriers): sync jobs, monitoring and log view, e-invoice or shipping steps where needed, documentation and hand-over.

The price shown on this service is the Starter package. For Standard or Advanced, send a message with your scope and I will reply with a written plan and a matching offer.

How it works: a written plan first, then milestones on a test environment with written updates, testing and adjustments, and a hand-over of the documentation. I work async-first in writing. You get a licence to use the delivered software for your business; Rui Codex keeps the source code (a source-code buy-out can be quoted on request).

Video overview (40 s): https://www.youtube.com/watch?v=tEUe7Dvx5vY