01 — About
An engineer who ships whole products.
I'm Muhammad Rehan, a full-stack and AI engineer based in Karachi, Pakistan, and Co-Founder & CTO of Assosiatix.
I take a product from an idea to a production system — the architecture, the backend and its APIs, the interface, the third-party integrations, and the servers it runs on. Most of my work sits where commerce and AI meet: Shopify, ad platforms, payments and language, image and video models.
I also completed a full course in Agentic AI, and I'm studying pre-engineering alongside working.
The clearest picture of how I work is in the case studies. For the company-side profile, see rehan.assosiatix.com.
02 — Timeline
Where I've worked.
- 2026 —
Full-Stack / Shopify Engineer
Startstorez
MERN stack and Shopify app development, building on Remix and Next.js.
- 2025 —
Co-Founder & CTO
Building AI-native SaaS products, marketing automation and Shopify infrastructure. Product architecture, backend APIs, integrations, deployment and production infrastructure.
- 2025 — 2026
Full-Stack Engineer
QF Network
MERN stack development, API integrations and Shopify app features.
03 — How I build
Habits, with receipts.
Patterns that repeat across my projects — each one links to where it shows up.
One implementation, shared
When two code paths must agree, they call the same function. SeamlessApply's results page and its cron job share a single job-matching module so they cannot drift apart.
See it in the case study →Assume the model misbehaves
GPT output arrives as markdown-wrapped JSON, malformed JSON or plain text. The CRM system parses in four layers and falls back to a template — it never crashes and never returns null.
See it in the case study →Isolate failures
Background jobs run per store or per seam with their own error handling and a dead-letter queue, so one bad record never stops the batch.
See it in the case study →Build for unattended operation
Cron and queues with rate limiting, deduplication and audit trails, so the system keeps running correctly when nobody is watching it.
See it in the case study →
04 — Toolbox
What I work with.
- Languages & frameworks
- TypeScript · Next.js · React · Node.js · NestJS · Remix
- Data & queues
- PostgreSQL · MongoDB · MySQL · Redis · BullMQ · Prisma · TypeORM
- AI
- OpenAI · Google Gemini · Veo · Pinecone · Agentic AI
- Commerce & integrations
- Shopify APIs · Stripe Connect · Meta Ads API · TikTok Ads API · Pipedrive
- Infrastructure
- Nginx · PM2 · Docker · Certbot / SSL · VPS deployment
05 — Education
Learning.
- 2023 —
F.S.C. Pre-Engineering
Government Intermediate Boys College, Karachi — in progress
- 2023
S.S.C., Board of Secondary Education, Karachi
Grade A
- Course
Agentic AI
Full course, completed