You will get expert API bug fixing and REST integration troubleshooting
Project details
A failing API halts your business. Let's fix it instantly.
Are users facing failed logins, blocked checkouts, or sync errors due to API crashes? Every minute of downtime costs revenue. You need an experienced full-stack architect to diagnose the exact root cause and deploy a secure fix.
I specialize in emergency API troubleshooting and repairing complex REST/GraphQL integrations to ensure your data flows seamlessly.
What I fix:
Broken API endpoints (500, 404 errors) & Server Crashes
CORS policy blockers & Authentication failures (JWT, OAuth)
Broken 3rd-party integrations (Stripe, Twilio, CRMs)
Webhook misconfigurations & JSON parsing issues
Why partner with me?
Rapid Response: Emergency debugging for critical apps.
Secure: Safe, isolated testing before deploying fixes.
Private: NDAs fully welcomed for your code's security.
Stop losing users over broken data. Message me your API issue, and let's get your platform running perfectly!
Are users facing failed logins, blocked checkouts, or sync errors due to API crashes? Every minute of downtime costs revenue. You need an experienced full-stack architect to diagnose the exact root cause and deploy a secure fix.
I specialize in emergency API troubleshooting and repairing complex REST/GraphQL integrations to ensure your data flows seamlessly.
What I fix:
Broken API endpoints (500, 404 errors) & Server Crashes
CORS policy blockers & Authentication failures (JWT, OAuth)
Broken 3rd-party integrations (Stripe, Twilio, CRMs)
Webhook misconfigurations & JSON parsing issues
Why partner with me?
Rapid Response: Emergency debugging for critical apps.
Secure: Safe, isolated testing before deploying fixes.
Private: NDAs fully welcomed for your code's security.
Stop losing users over broken data. Message me your API issue, and let's get your platform running perfectly!
Programming Languages
PHP, JavaScript, TypeScriptCoding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$25
|
Standard
$60
|
Advanced
$150
|
|---|---|---|---|
| Delivery Time | 1 day | 2 days | 3 days |
Number of Revisions | 1 | 3 | Unlimited |
Bug Investigation | |||
Fix Documentation | - | - | |
Detailed Code Comments | - |
Frequently asked questions
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NG
Ned G.
Jul 7, 2026
Build for custom Webflow website
Zubair built a website in Webflow from copy revision through domain migration, handling the full technical scope: staging build, inquiry form backend and email delivery, cross-browser and mobile QA, and the live cutover with redirects, SSL, and analytics. He hit every milestone on schedule, held his work to a high standard before sending anything over for review, and was consistently fair and transparent about scope, which made the whole engagement easy and pleasant to manage. I'd hire him again without hesitation, am in fact planning on working with him again, and I recommend him to anyone who needs a Webflow build done properly.
NG
Ned G.
Apr 26, 2026
Squarespace Website Development
Zubair was a true partner to me on this project. I really enjoyed working with him and greatly appreciated his dedication, guidance, and expertise. Zubair was an excellent and clear communicator, as well as being flexible and responsive; a pleasure to recommend.
SA
Sohail A.
Feb 1, 2024
Responsive Design Expert Needed for Existing WordPress Website
Outstanding job! Zubair Ali efficiently made our WordPress website fully responsive, exceeding expectations. Their expertise, prompt communication, and early delivery deserve a solid 5-star rating. Highly recommended!
SK
Staven K.
Mar 2, 2023
Need Services and a gallery page for my wordpress site
Zubair did the everything we needed him to do for our website! I highly recommend his services and talent, I would be glad to work with him again.
NA
Nazeer A.
Apr 9, 2022
Logo For LB
Great communication, great skills, project finished way ahead of schedule. I would be glad to work with Zubair again.
I recommend him highly.
I recommend him highly.
About Zubair
Full-Stack AI Engineer | React, Next.js, Node.js & AI Integration
100%
Job Success
Karachi, Pakistan - 8:17 pm local time
I specialize in building complete, scalable web applications powered by custom AI workflows. From production-ready SaaS platforms to private-data AI chatbots using Retrieval-Augmented Generation (RAG), I handle everything from UI/UX to backend data pipelines and LLM infrastructure.
If you need to build a high-performing web application from the ground up or connect modern AI to your private documents, databases, and APIs, I deliver secure, fast, and maintainable software.
Core Focus Areas:
AI SaaS Development: End-to-end multi-tenant web applications, user authentication, subscription billing (Stripe), dashboard analytics, and seamless AI feature integration.
Custom AI Chatbots & RAG: Context-aware conversational agents, private document querying (PDF, CSV, Notion, API sync), vector search, and hallucination-reduced LLM outputs.
Frontend Engineering: Next.js (App Router, Server Components), React, TypeScript, Tailwind CSS, and real-time streaming UI (AI chat responses).
Backend & Data Pipelines: Node.js, Express, FastAPI/Python, REST & GraphQL APIs, Supabase, PostgreSQL, MongoDB, Redis, and automated vector indexing.
Tech Stack:
AI / LLMs: OpenAI API, Claude API, LangChain, LlamaIndex, Pinecone, ChromaDB, Vector Embeddings, Prompt Engineering.
Web & Full-Stack: Next.js, React.js, Node.js, TypeScript, Python, Tailwind CSS, REST APIs.
Database & Cloud: PostgreSQL, Supabase, MongoDB, AWS, Docker, Vercel.
Why Work With Me:
End-to-End Ownership: Direct technical execution from architecture design to deployment.
Production-Grade AI: Scalable token management, response streaming, caching, and rate limiting to control API costs.
Clean & Maintainable: Modular code, well-documented endpoints, and clear communication.
Send over a brief description of your project or idea, and let’s discuss how to build it efficiently.
Steps for completing your project
After purchasing the project, send requirements so Zubair can start the project.
Delivery time starts when Zubair receives requirements from you.
Zubair works on your project following the steps below.
Revisions may occur after the delivery date.
Diagnosis & Log Analysis
I will securely review your source code, reproduce the bug in a safe environment, and analyze server logs to identify the root cause of the API failure
Implementation & Bug Fixing
I will write the necessary code fixes, correct configurations (like CORS or webhooks), and ensure the changes do not break any existing backend features.