You will get a custom web application feature with backend and API development
Project details
I will help you add a clearly defined API-powered feature to your existing web application.
Depending on what your application already has, I can build the backend/API only, connect it to an existing screen, or complete the feature across the frontend, backend, and database.
This service is suitable for features such as forms, data management tools, admin functions, search and filtering, status updates, secure user actions, and custom business workflows.
Before development begins, I will review the feature you need and the relevant part of your application to confirm the best approach and make sure the selected package matches the work involved.
Each package covers one agreed feature. Larger workflows, several separate modules, major architecture changes, complex background processing, or broader application development may need a separate estimate.
Depending on what your application already has, I can build the backend/API only, connect it to an existing screen, or complete the feature across the frontend, backend, and database.
This service is suitable for features such as forms, data management tools, admin functions, search and filtering, status updates, secure user actions, and custom business workflows.
Before development begins, I will review the feature you need and the relevant part of your application to confirm the best approach and make sure the selected package matches the work involved.
Each package covers one agreed feature. Larger workflows, several separate modules, major architecture changes, complex background processing, or broader application development may need a separate estimate.
Programming Languages
ASP.NET, TypeScript, C#Coding Expertise
Cross Browser & Device Compatibility, Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$99
|
Standard
$299
|
Advanced
$499
|
|---|---|---|---|
| Delivery Time | 2 days | 4 days | 7 days |
Number of Revisions | 1 | 1 | 2 |
Number of Pages | 0 | 1 | 2 |
Design Customization | - | ||
Content Upload | - | - | - |
Responsive Design | - | ||
Source Code |
Optional add-ons
You can add these on the next page.
Additional Revision
+$35
Additional simple API action
(+ 1 Day)
+$75Frequently asked questions
About Katerina
Full-Stack Developer | APIs, C#, ASP.NET Core, React, Node.js, SQL
Sderot, Israel - 8:49 am local time
I work with C#, ASP.NET Core, .NET, SQL/PostgreSQL, React, and Node.js when needed. I can help with backend development, API design, database design, third-party integrations, admin panels, internal tools, bug fixing, performance improvements, and deployment support.
My experience includes production systems, web control panels, mobile-connected backends, data-processing workflows, background jobs, internal tools, and the full development lifecycle from planning and architecture to implementation and deployment.
I can also help with practical AI integrations, including OpenAI/LLM API features, AI-powered workflows, RAG/backends, vector search, and connecting AI functionality with existing APIs, databases, and business logic.
I’m comfortable working with existing codebases, investigating issues, improving maintainability, and turning unclear technical problems into practical solutions. I value clear communication, reliable delivery, and clean, maintainable code.
Steps for completing your project
After purchasing the project, send requirements so Katerina can start the project.
Delivery time starts when Katerina receives requirements from you.
Katerina works on your project following the steps below.
Revisions may occur after the delivery date.
Review the feature and confirm the approach
I review your requirements and the relevant part of your application to confirm the best implementation approach before development begins.
Build the API-powered feature
I build the agreed feature across the backend, database, and interface where needed, including validation and clear error handling.