You will get Next.js bug fixes and Supabase security for your production app
Top Rated
Top Rated
Project details
Applications built quickly, by several developers, or by AI tools, tend to fail in the same places. Auth that only checks on the frontend. Data that does not refresh until you reload. A database that trusts anyone holding a key that is visible in the browser.
They work in a demo. They do not hold up with real users.
I fix that. Next.js, React, TypeScript, Node and Supabase.
The thing I care most about is finding the actual cause rather than patching where the symptom appears. If the same mistake exists in three other places, patching one of them means you will be back here next month.
Every order comes with a short written note: what was wrong, why it happened, what changed, and anything else worth your attention. Written so a non-technical founder can follow it.
If I look at your code and think the problem is not worth fixing, or is bigger than the tier you ordered, I will tell you before doing the work rather than after.
Top Rated on Upwork with a 100% Job Success Score.
They work in a demo. They do not hold up with real users.
I fix that. Next.js, React, TypeScript, Node and Supabase.
The thing I care most about is finding the actual cause rather than patching where the symptom appears. If the same mistake exists in three other places, patching one of them means you will be back here next month.
Every order comes with a short written note: what was wrong, why it happened, what changed, and anything else worth your attention. Written so a non-technical founder can follow it.
If I look at your code and think the problem is not worth fixing, or is bigger than the tier you ordered, I will tell you before doing the work rather than after.
Top Rated on Upwork with a 100% Job Success Score.
Programming Languages
JavaScript, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Localization, Performance OptimizationWhat's included
| Service Tiers |
Starter
$200
|
Standard
$400
|
Advanced
$750
|
|---|---|---|---|
| Delivery Time | 3 days | 6 days | 10 days |
Number of Revisions | 2 | 4 | 6 |
Bug Investigation | |||
Fix Documentation | |||
Detailed Code Comments | - |
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JW
Jelecia W.
Aug 12, 2026
Need React, Next.js, Node/Express and API Integration Developer
Excellent!
Clear communication!
High quality!
Clear communication!
High quality!
SA
Saud A.
Jan 18, 2026
Full stack Devoloper
Zekariyas is a talented Full Stack Developer. He handled both frontend and backend tasks with great proficiency and delivered a robust solution. He writes clean code and is very knowledgeable about modern web technologies. I was impressed by his problem-solving skills and ability to deliver on time. Highly recommended
RS
Rovshan S.
Nov 28, 2025
Deployment of vendor-panel to Vercel
Very fast, reliable and cooperative.
OO
Oluwole O.
Aug 5, 2025
React Frontend Developer for Enhancements and Payment Integration
Zekariyas was a great freelancer, pleasure to work with him.
BW
Blake W.
Apr 17, 2024
Basic woocommerce cart styling
About Zekariyas
Full-Stack Developer | Next.js, React, Node.js, API | AI SaaS MVPs
100%
Job Success
Addis Ababa, Ethiopia - 12:59 am local time
I am Full-Stack Developer building AI SaaS MVPs in Next.js, React and Node.js. From empty repo to deployed: frontend, backend, database, API integration, and AI that survives real users.
Your AI feature works in the demo. Then a real user touches it and it falls over.
Or the MVP that was six weeks out is now four months late. Or the API between two systems breaks every time one of them changes.
Here's what usually goes wrong. Most developers can wire up an OpenAI call. Far fewer build the backend that survives one: retries when the API times out, caching so you're not paying twice for the same answer, a schema that doesn't need rewriting the moment you add a second feature. That gap is where MVPs die, and it's the part I actually care about.
WHAT I BUILD AS A FULL-STACK DEVELOPER
"WE NEED AN MVP IN WEEKS, NOT MONTHS."
Next.js App Router, React, Node.js, Supabase with Row-Level Security, auth with roles, multi-tenant ready. I've shipped this stack enough times that the boring 60% goes fast, which leaves real time for the part that's actually yours. Full stack means full stack here: frontend, backend, database, deploy. You get a working product at every milestone, not a big reveal at the end.
"THESE TWO SYSTEMS DON'T TALK TO EACH OTHER." — API INTEGRATION
API integration is most of real product work. Stripe billing, third-party REST APIs, webhooks, OAuth, and the error handling nobody writes until it breaks in production. I've built payment integration, marketplace deployment and custom API layers on live client products, in React and Node.js.
"OUR CHATBOT MAKES THINGS UP."
Generic LLM output isn't a prompt problem, it's a retrieval problem. I build RAG systems that answer from your documents, your data, using vector search on Supabase pgvector so every response is grounded in something real. Built exactly this for a coaching platform: GPT-4 answering from the client's proprietary framework instead of guessing, with citations back to the source.
"OUR BACKEND IS SLOW AND WE DON'T KNOW WHY."
Usually queries, sometimes caching, occasionally architecture. I cut backend latency 60% through PostgreSQL query optimization and Redis caching across Node.js services. If your Next.js app is slow, I'll find out why before I start rewriting things.
HOW I WORK
Scope before I build, so you know what's in version one and what waits.
Working product at every milestone, not a reveal at the end.
I write the code myself. No team behind me, no mystery contractor.
You get the keys: README, deploy pipeline, env setup. Nothing you can't hand off.
Replies inside four hours. Addis Ababa, GMT+3: full overlap with Europe, afternoons with US East Coast.
THE STACK
Frontend: Next.js (App Router, Server Components), React, TypeScript, Tailwind CSS
Backend: Node.js, Express, REST APIs, Python
Database: PostgreSQL, Supabase, Redis, MongoDB
AI: OpenAI, Claude, Gemini, RAG, embeddings, pgvector
Payments and auth: Stripe, JWT, OAuth, RBAC
Infra: Docker, AWS, Vercel, CI/CD
Top Rated, 100% Job Success, every contract closed clean.
TESTIMONIALS
"Zekariyas is a talented Full Stack Developer. He handled both frontend and backend tasks with great proficiency and delivered a robust solution. He writes clean code and is very knowledgeable about modern web technologies. I was impressed by his problem-solving skills and ability to deliver on time. Highly recommended"
"I engaged Zekariyas as a Fullstack developer to help build, deploy, and customize a marketplace application using Next.js and Vercel. He performed exceptionally well — always responsive, quick to solve problems, productive, and highly reliable. His expertise significantly contributed to the success of the project. I would gladly hire him again at the next opportunity."
So: building an AI SaaS MVP in Next.js, adding an API integration to a React app you already have, or fixing a Next.js and Node.js build that isn't holding up? Tell me what's going on. I'll tell you straight how I'd approach it and roughly what it takes. If I'm not the right person, I'll say that too.
Full-Stack Developer · Next.js Developer · React Developer · Node.js Developer · Full-Stack Development · Next.js Development · React.js · Express · TypeScript · API Integration · API Development · REST API · Third-Party API · Webhooks · Supabase · PostgreSQL · Stripe Integration · SaaS Development · MVP Development · Startup MVP · AI SaaS · AI App Development · OpenAI API · RAG · Vector Search · pgvector · Multi-Tenant SaaS · Server Components · Row-Level Security
[Updated: August 26]
Steps for completing your project
After purchasing the project, send requirements so Zekariyas can start the project.
Delivery time starts when Zekariyas receives requirements from you.
Zekariyas works on your project following the steps below.
Revisions may occur after the delivery date.
Reproduce it
Before diagnosing anything I make the problem happen on my machine. A fix for a bug you cannot reproduce is a guess.
Find the actual cause
The visible symptom is usually not the cause. I trace it back rather than patching where it appears.