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I will be your dotnet developer for asp net core web apps and rest apis
Selman Altinay
About this gig
Need a business web application, customer portal or REST API that is built properly and easy to maintain? I build them end to end in C# and ASP.NET Core, with SQL Server or PostgreSQL.
What I deliver:
- Web applications and portals with login, roles, forms, reports and admin pages
- REST APIs with clear documentation, validation and error handling
- Database design and migrations (SQL Server or PostgreSQL)
- Background jobs, e-mail and integrations with other systems
- Deployment on Azure, a VPS or Docker, plus written documentation. You get a licence to use the delivered software; Rui Codex keeps the source code (buy-out quoted on request).
I can also extend or fix an existing .NET application: new features, performance, security and upgrades.
Delivered before: a modular web ERP (purchasing, sales, export, finance, warehouse), integration platforms between marketplaces and accounting, and a GDPR and KVKK consent management platform.
How we work: async-first, in writing. We agree the scope and milestones in writing, and you can test each milestone before the next one starts.
Please send a message before ordering so we can confirm the scope and the right package.
Get to know Selman Altinay
Selman Altinay
Senior full stack developer, ERP and ecommerce integrations, AI automation
- FromBelgium
- Member sinceOct 2026
- Avg. response time9 hours
Languages
Turkish, English, Dutch
I'm Selman Altinay, a Belgium-based software engineer (Rui Codex) building business software end to end: web apps and APIs in C#/ASP.NET Core with SQL Server or PostgreSQL, and integrations between systems that don't talk to each other. Delivered work includes a modular web ERP, real-time marketplace-to-accounting sync with e-invoices, a PrestaShop pipeline to accounting and four carriers, PLC/SCADA data collection, and EveryTranslate, Rui Codex's own AI translation SaaS. I also build AI/n8n workflow automation. I work async-first in writing, in short milestones.
Other Software Development Services I Offer
FAQ
Can you work on my existing .NET project?
Yes. I can add features, fix bugs or upgrade an existing ASP.NET or ASP.NET Core application. I first review the code and confirm the scope in writing.
Which front end do you use?
By default server-rendered Razor views with Bootstrap, which are fast and simple to maintain. If you already use another front end, I can build the API for it.
Where is the app hosted?
On your Azure account, your own server or a Docker host. I set up the deployment and document it.
Do I get the source code?
No. You get a licence to use the delivered software for your business, plus the written documentation; Rui Codex keeps the source code. A source-code buy-out can be quoted on request.
