You will get Add a Custom Feature to Your Existing Web App — Clean, Integrated Code
Project details
Need a new feature built into your existing web app — without breaking what already works?
I specialize in feature integration on live codebases. That means I read your existing
patterns, match your architecture, and deliver code that feels like it was always there.
I can build:
✦ New pages, routes, or views (React, Vue, Next.js, plain HTML)
✦ Forms with validation, multi-step flows, file uploads
✦ API integrations (REST, GraphQL, third-party services)
✦ Search, filter, sort, and pagination on existing data
✦ User permissions / role-based UI logic
✦ Dashboard widgets, charts, and data tables
✦ Notification systems, modals, drawers, and toasts
✦ Any other self-contained feature you can describe
My approach:
→ I read your codebase before writing a single line
→ I match your existing stack, conventions, and folder structure
→ I deliver a clean PR or diff — no rewrites, no scope creep
5+ years building enterprise-grade web features used daily by real users.
I specialize in feature integration on live codebases. That means I read your existing
patterns, match your architecture, and deliver code that feels like it was always there.
I can build:
✦ New pages, routes, or views (React, Vue, Next.js, plain HTML)
✦ Forms with validation, multi-step flows, file uploads
✦ API integrations (REST, GraphQL, third-party services)
✦ Search, filter, sort, and pagination on existing data
✦ User permissions / role-based UI logic
✦ Dashboard widgets, charts, and data tables
✦ Notification systems, modals, drawers, and toasts
✦ Any other self-contained feature you can describe
My approach:
→ I read your codebase before writing a single line
→ I match your existing stack, conventions, and folder structure
→ I deliver a clean PR or diff — no rewrites, no scope creep
5+ years building enterprise-grade web features used daily by real users.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, DesignWhat's included
| Service Tiers |
Starter
$150
|
Standard
$300
|
Advanced
$550
|
|---|---|---|---|
| Delivery Time | 3 days | 6 days | 9 days |
Number of Revisions | 1 | 2 | 3 |
Number of Pages | 1 | 3 | 5 |
Design Customization | |||
Content Upload | |||
Responsive Design | |||
Source Code |
Frequently asked questions
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WS
Wassim S.
Jul 4, 2026
fix a bug in my web site
Great experience working with Marwen. He delivered fast, communicated clearly throughout, and kept me updated at every step. Quick to understand what I needed and easy to work with would definitely hire again
About Marwen
Senior Full Stack React Node.js Three.js React Native
Lisbon, Portugal - 12:05 am local time
Web · Mobile · 3D · Performance · Security
Freelance, B2B & contract — DM or email to get started.
Steps for completing your project
After purchasing the project, send requirements so Marwen can start the project.
Delivery time starts when Marwen receives requirements from you.
Marwen works on your project following the steps below.
Revisions may occur after the delivery date.
Codebase Analysis & Scope Review
You share access to your repository (GitHub/GitLab) along with the feature requirements. I review your existing architecture, folder structure, and coding style to ensure seamless integration without breaking anything.
Implementation Planning
I draft a quick implementation plan outlining how the new feature will hook into your state management, API routes, or UI components. We align on this plan before writing any code.