Full-Stack Engineer · TypeScript / React / Node.js

Available for work

MohsenMirzaei

I build production web platforms — React/Next.js frontends, Node.js/Fastify services, real-time systems, and RAG-powered AI products.

Message on Telegram↗Get in touch Download resume↓

Isfahan, IranGMT+3:30

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01About

Engineer who ships whole products, not just screens.

Portrait of Mohsen Mirzaei, Full-Stack Engineer

I'm Mohsen, a full-stack engineer who thinks in TypeScript systems. Over 4+ years I've built real-time trading platforms, AI products, and fintech apps — owning React frontends, Node.js services, testing, CI/CD, and observability through production.

Architecture-first

Monorepos, Feature-Sliced Design, shared contracts, and clean boundaries — I build TypeScript systems that scale with the team.

Real-time obsessed

WebSocket pipelines with ref-counted subscriptions, reconnect, throttled cache patching, and production observability.

End-to-end ownership

From React interfaces to Fastify services, tests, CI/CD, and observability — I keep ownership through production.

Years building for production

Products shipped

14k+

Fintech users served

100%

Ownership, idea to deploy

React 19✦TypeScript✦Next.js✦WebSocket✦Three.js✦GSAP✦TanStack Query✦Turborepo✦Feature-Sliced Design✦Node.js✦Fastify✦PostgreSQL✦Redis✦Tailwind CSS✦Zustand✦Zod✦Docker✦OpenTelemetry✦React 19✦TypeScript✦Next.js✦WebSocket✦Three.js✦GSAP✦TanStack Query✦Turborepo✦Feature-Sliced Design✦Node.js✦Fastify✦PostgreSQL✦Redis✦Tailwind CSS✦Zustand✦Zod✦Docker✦OpenTelemetry✦

02Experience

Eight products across crypto, fintech & AI.

Sep 2025 – Present

Restaurant Reservation Platform

Full-Stack Engineer · Freelance, Part-Time

US-client reservation platform unifying event hall, catering, and table bookings into a 4-app monorepo with self-service booking flows and production observability.

Unified 3 booking channels into a 4-app monorepo with 21 customer/admin screens, replacing phone-based intake with self-service flows.
Designed the reservation core — an 8-state lifecycle with transactional slot locking — preventing double-bookings and invalid transitions.
Enforced single-source API contracts via 77 shared Zod schemas and 72 automated tests across auth, booking, and audit paths.
Set up async BullMQ notifications (Twilio/Resend) off the HTTP path and a 9-service observability stack targeting p95 <500 ms.

TypeScriptReactNext.jsFastifyPostgreSQLRedisBullMQ

double-bookings under load

shared API schemas

automated tests

Aug 2025 – Apr 2026

RcoinX

Senior Frontend Software Engineer

Architected the frontend platform for a pre-launch crypto exchange, from monorepo foundations to real-time Spot Trading and account-security flows.

Architected the frontend from scratch — Turborepo monorepo with 8 shared packages and strict Feature-Sliced Design import boundaries — authoring 61% of commits in a 3-engineer team.
Delivered Spot Trading end-to-end (~9.5K LOC): order book, charts, order management, 9 REST integrations, and 3 WebSocket streams.
Built a centralized WebSocket layer with ref-counted subscriptions, auto-reconnect, and 200–300ms throttled cache patching for market data.
Shipped Account & Security with TOTP, WebAuthn, MFA-gated flows, RTL/LTR Storybook components, and Vitest + MSW tests in Docker CI.

React 19TypeScriptTanStack RouterTanStack QueryZustandWebSocketTurborepo

61%

of frontend commits

shared packages

WebSocket streams

Apr 2025 – Jul 2025

Isopoll

Frontend Software Engineer

Frontend engineer on a fully RTL Persian B2B SaaS platform spanning surveys, recruitment, consultation booking, and digital commerce.

Engineered a 35K+ LOC, 41-page Next.js enterprise platform across 6 business modules in 4 months.
Structured the data layer with 85 React Query hooks, 86 typed services, and 18 API domains, cutting new-endpoint work to one hook.
Standardized 23+ production forms on 41+ Zod schemas, with hybrid SSR and tag-based revalidation across 31+ modules.

Next.js 15TypeScriptApp RouterTanStack QueryZustandZodReact Hook Form

pages shipped

typed services

Apr 2025 – Jul 2025

Propx

Frontend Engineer · Freelance, Part-Time

Bilingual hedge fund platform — multi-step KYC onboarding, role-based dashboards, and a support ticketing system for customer verification workflows.

Developed an 11-step KYC wizard with in-browser ID capture and video recording, completed in a single web session.
Delivered 18 role-gated screens across public, user, and super-admin areas, integrating 36 REST endpoints via 30 typed hooks.
Implemented a bilingual EN/FA interface with ~1,700 localized strings and 6 Zod-validated forms shared across auth, KYC, and ticket flows.

Next.js 15React 19TypeScriptTailwind CSSshadcn/uinext-intlTanStack Query

Oct 2024 – Mar 2025

Chatomatic

Co-Founder & Full-Stack Engineer

Co-founded and launched an AI assistant SaaS, then rebuilt the platform end-to-end with dashboard, playground, RAG retrieval, and a Shadow DOM embed.

Co-founded and launched to 100+ users; rebuilt it end-to-end solo in 2026 (~25K LOC) across dashboard, playground, and Shadow DOM embed.
Built a greenfield Fastify API with 7 modules, 27 Result-typed use-cases, 11 tables, public embed routes, and per-assistant OpenAI/Ollama routing.
Designed 2-phase streaming chat: pgvector top-5 retrieval, token stream, then post-stream citation persistence.
Implemented hybrid RAG: IVFFlat top-5 retrieval with full-context fallback, inline numbered citations, and a 5-format ingestion pipeline.

Next.js 15React 19TypeScriptFastifyVercel AI SDKOpenAI SDKpgvector

100+

users at launch

25K

LOC rebuilt end-to-end

Feb 2024 – Sep 2024

IT Barbod

Full-Stack Engineer

Led frontend delivery across three products in an on-site product team — a no-code app builder, a full-stack form builder, and an RTL markdown editor.

Built a drag-and-drop app builder enabling non-technical teams to ship React Native screens without engineering, cutting screen delivery from multi-day dev cycles to hours.
Architected an RTL-first Markdown editor on Monaco with 24+ authoring commands.
Created a schema-driven UI system with a Draft → Merge → Publish → Rollback lifecycle and a form builder with 11 field types on Next.js, Prisma, and PostgreSQL.

ReactTypeScriptNext.jsViteTailwind CSSRadix UIdnd-kit

2023 – 2024

HeidaryHa

Frontend Engineer · Contract

Mobile banking PWA serving 14,000+ customers, with multi-factor auth and high-reliability financial transaction workflows.

Launched a production mobile-banking PWA serving 14,000+ customers, building its authentication and transaction flows.
Contributed to a 40% increase in monthly loan applications, shipping PWA + Android from a single React/TypeScript codebase.

ReactTypeScriptViteTanStack QueryPWACapacitorZod

14k+

customers served

40%

more monthly applications

2021 – 2023

Motion Desk

Software Engineer

Collaborated with motion and product designers to build and publish two commercial Adobe After Effects extensions on aescripts.com.

Shipped 2 commercial cross-platform After Effects (CEP) extensions on aescripts.com.
Reached 3,000+ downloads and 1,000+ sales by translating designer workflows into optimized extension UIs.

JavaScriptHTMLCSSAdobe CEPAfter Effects

3k+

downloads

1k+

sales

03Selected Work

Things I've designed& engineered.

Four featured builds with full write-ups — scroll sideways, or open a case study for the architecture behind it.

RcoinX spot trading interface — order book, candlestick chart, and order form

Crypto · Real-time

RcoinX Trading Platform

Pre-launch spot cryptocurrency exchange frontend built from scratch on a Turborepo monorepo with strict Feature-Sliced Design boundaries.

React 19TypeScriptWebSocketTanStackTurborepoTailwind

2025Case study→

Chatomatic dashboard — streaming AI chat with inline citations and assistant playground

AI · Full-Stack · Co-Founder

Chatomatic — AI SaaS

AI assistant SaaS launched to 100+ users and rebuilt end-to-end with RAG retrieval, streaming chat, and an embeddable widget.

Next.js 15FastifyVercel AI SDKpgvectorShadow DOMRollup

2024–2026Case study→

Full-Stack · System Design

Restaurant Reservation Platform

A 4-app reservation monorepo for event halls, tables, and catering with concurrency-safe booking for a US-market launch.

Next.jsReactFastifyPostgreSQLRedisBullMQ

2025Case study→

Grafana dashboard with correlated metrics, logs, and distributed traces for a Fastify API

Open Source · Observability

Fastify Observability Stack

A production-grade Fastify API with unified metrics, logs, and distributed tracing — built to debug requests end-to-end in Grafana.

TypeScriptFastifyPostgreSQLRedisOpenTelemetryPrometheus

2026GitHub↗

More work

RTL markdown editor — Monaco editor pane with live preview of Persian book content

Product · Editor

2024

RTL Markdown Book Editor

A Monaco-based, RTL-first markdown authoring studio with split-pane live preview and multilingual insertion workflow.

24+ authoring commands with split-pane live preview and TOC navigation.
markdown-it rendering pipeline with anchor, footnote and media plugins.

ReactTypeScriptMonacomarkdown-itTanStack Query

No-code app builder — drag-and-drop canvas composing a mobile screen from components

Product · Schema-driven

2024

No-Code App & Form Builders

Drag-and-drop builders that let non-technical teams ship mobile screens and forms without engineering.

Schema-driven component system with Draft → Merge → Publish → Rollback lifecycle.
WYSIWYG form designer with 11 configurable field types and runtime rendering.

ReactNext.jsTypeScriptdnd-kitPrismaPostgreSQL

04Capabilities

A full-stack toolkit, frontend-first.

Languages

TypeScript
JavaScript (ES2022+)
SQL
Go (familiar)

Frontend

React 19
Next.js 15
Vite
React Router Dom
TanStack Router
TanStack Query
Zustand
React Hook Form
Framer Motion

Architecture & Quality

Feature-Sliced Design
Monorepo · Turborepo/pnpm
Vitest
MSW
Docker
CI/CD
Schema-Driven UI

UI & Styling

Tailwind CSS
Radix UI
shadcn/ui
Storybook
RTL / LTR · i18n
Accessibility (a11y)
Figma-to-code

Backend & Data

Node.js
Fastify
Prisma
PostgreSQL
Redis
pgvector
BullMQ
Zod

Auth & Security

WebAuthn
JWT
OAuth
OTP
RBAC
Rate Limiting

Testing & Quality

Vitest
MSW
k6
ESLint (architecture rules)
TypeScript strict
CI/CD

AI & Observability

Vercel AI SDK
OpenAI SDK
RAG
OpenTelemetry
Prometheus
Loki
WebSocket
Streaming UI

05Courses

Learning stays a habit, not an event.

Self-directed study, tracked honestly — none of these are accredited certificates, just hours logged outside of work.

Courses taken

243+

Hours of training

In progress now

Go Casts

visit →

Go & Backend Bootcamp (with team-building)
In progress
40h
- Go language fundamentals and idiomatic backend patterns
- Cloud-native app design, containers, and Kubernetes basics
- Event-driven / message-driven architecture in practice
- Code reviews and team-building inside a real engineering team

Behrad Zari

visit →

System Design 1–4 — Observability to Microservices
In progress
51h
- Scalability, observability, and resource estimation for production services
- Resilience patterns and async processing with queues and brokers
- Multi-database architectures, replication, and sharding for high availability
- Microservices migration strategy, service boundaries, and org-scale tradeoffs
Art of Coding
21h
- Software engineering fundamentals and systems thinking at the code level
- Layered, modular design for reusable components in real projects
- Production-readiness checklist for shipping projects
- Clean code practices and reducing technical debt

Code with Mosh

visit →

06References

What people say after we ship together.

“Mohsen is a highly innovative, constantly evolving programmer who strives to deliver exceptional outcomes. He has a proven track record of completing challenging projects on time and within budget, and his passion for the craft shows in his attention to detail.”

“Mohsen is one of the most hardworking and creative colleagues I've had the pleasure of working with. He combines strong technical expertise with excellent soft skills — curiosity, punctuality, and attention to detail — that make him a valuable asset to any team.”

“Mohsen is one of the most creative and motivated front-end developers I know — always full of fresh ideas, and he never backs down when things get tough. Working with him, or even just talking to him, is genuinely inspiring.”

“What stood out most about Mohsen was his persistence — he wouldn't step away from his desk until he'd solved the problem at hand. He's someone who constantly strives to improve, getting sharper every single day.”

Show more recommendations→

07Notes

Writing about the hard parts.

May 2026 · 8 min

A ref-counted WebSocket layer for real-time market data

How to feed an order book that updates dozens of times per second without melting React: shared subscriptions, throttled cache patching, and reconnect that replays state.

WebSocketReactReal-timeArchitecture

→

Jun 2026 · 7 min

Preventing double-bookings with transactional slot locking

Two customers race for the last table at 2 a.m. Why check-then-write always loses, and how row locks plus a state machine make double-booking unrepresentable.

PostgreSQLConcurrencySystem DesignFastify

→

07Contact

Let's build something people remember.

Open to full-stack & senior frontend roles · Remote (GMT+3:30) · Open to relocation (EU). Whether it's a real-time platform, an AI product, or a fintech app — I'd love to hear about it.

hello@mohsenmirzaei.com→

Message on Telegram↗

Elsewhere

GitHub↗LinkedIn↗X / Twitter↗