Behzad Fattahi

The long-form version — real architecture decisions with their costs included — is on the blog.

• SaaS & Platforms

  Multi-Tenant SaaS Platform

  Mediana — cloud-native backend + React dashboards

  A multi-tenant SaaS product behind a YARP gateway: every request authenticates at the identity service, then routes to .NET 10 microservices talking gRPC with per-service Redis caches. Apache Kafka absorbs the high-throughput ingress, SQL Server serves hot data with a ClickHouse cold archive cutting storage costs, and the whole fleet runs highly available on Kubernetes.

  • ~2k RPS with p99 of 60ms on hot endpoints
  • 25% lower infrastructure costs (ClickHouse cold archive)
  • 40% faster queries after SQL Server tuning
  • OpenTelemetry tracing into SigNoz, errors to Splunk

  • .NET 10/8
  • C#
  • React
  • YARP
  • gRPC
  • Apache Kafka
  • SQL Server
  • ClickHouse
  • Redis
  • Kubernetes
  • Azure

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• IoT

  Multi-Tenant IoT Platform

  IroTeam — devices, apps, and hardware on one platform

  An IoT platform managing 5,000+ connected devices with real-time processing of 2M+ daily events: .NET microservices with MQTT ingestion, Nuxt web apps, an Angular admin dashboard, and hardware integrations from greenhouses to access control.

  • 5,000+ devices, 2M+ events/day, 99.8% uptime
  • Nuxt web apps + Angular admin dashboard
  • Greenhouse & access-control hardware integrations

  • .NET 8/5
  • C#
  • Nuxt
  • Angular
  • MQTT
  • SQL Server

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• Fintech

  Crypto BI

  Wallex — signal backtesting & market intelligence

  The fintech line of work, with signal backtesting at its core: Kafka and Microsoft Orleans actor pipelines replay the full signal set against point-in-time market data, feeding a ~780-file C# BI backend with a dedicated query API and Nuxt dashboards. The same foundations carried the TradeX BI data warehouse — Orleans aggregation grains behind a Next.js analytics dashboard — and TDX.bz, shortlisted among 35 of 1,043 startups for the Web Summit Qatar 2025 PITCH competition.

  • Signal backtesting: 5M+ events/day on Kafka + Orleans actors
  • 99.9% uptime after the Kafka migration
  • ~780-file C# BI backend, 500+ personal commits
  • TradeX BI: Orleans data warehouse + Next.js analytics
  • TDX.bz: top 35 of 1,043 — Web Summit Qatar 2025 PITCH

  • .NET 6
  • C#
  • Microsoft Orleans
  • Nuxt
  • Next.js
  • Python
  • Apache Kafka
  • SQL Server
  • SingleStore DB
  • Redis

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• SaaS & Platforms

  Shahrzad Platform

  Audiobook platform — mobile, dashboard, and backend

  The Shahrzad audiobook & podcast platform, built full stack: an ASP.NET Zero backend of 1,500+ C# files with a GraphQL API, the React Native consumer app, and the Angular creator dashboard — install and download analytics, paid-subscriber play-time metrics driving creator revenue share, and financial reports with CSV export.

  • 1,500+ C# file backend with GraphQL API
  • React Native app + Angular creator dashboard
  • Play-time based creator revenue share

  • .NET
  • C#
  • GraphQL
  • React Native
  • Angular
  • SQL Server

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• Mobile

  KetabGB

  React Native audiobook & podcast app

  A React Native audiobook & podcast app for iOS and Android that I built solo: streaming playback, subscriptions with in-app payment (Charkhone SDK), and catalog discovery over a GraphQL API via Apollo Client with persisted cache — one codebase, both stores.

  • Single React Native codebase for iOS + Android
  • Streaming playback + in-app subscription flows
  • Apollo GraphQL with offline-persisted cache

  • React Native
  • JavaScript
  • GraphQL
  • Firebase

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• SaaS & Platforms

  VisualMeet

  Video-conferencing platform on ASP.NET Zero

  A full video-conferencing product: WebRTC meeting rooms with camera and mic controls, screen share, in-meeting chat, participants, recording, and file sharing — an ASP.NET Zero modular monolith (.NET 5) with an Angular 12 panel, SignalR signaling, a GraphQL endpoint, and Xamarin mobile heads.

  • WebRTC rooms: video, screen share, chat, recording, files
  • SignalR signaling + GraphQL API on a DDD-layered monolith
  • Angular 12 panel + Xamarin iOS/Android heads

  • .NET 5
  • ASP.NET Zero / ABP
  • Angular
  • SignalR
  • WebRTC
  • GraphQL

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• SaaS & Platforms

  Daneshmand

  Meeting-room reservation & management

  An online reservation platform for meeting rooms (Asarad, 2018–2019) built full stack with Angular and .NET: guest invitations with QR access codes, meeting locations with maps and parking info, in-meeting polls and votes, shared meeting files, and notes.

  • Room booking with guest invitations & QR access
  • Meeting polls, votes, shared files, and notes

  • .NET Core 2
  • C#
  • Angular
  • SQL Server

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• SaaS & Platforms

  Tamland.ir

  Live online exam-prep classroom

  An online entrance-exam class platform I built as primary author (2019–2021, the lms-famiran codebase): an ASP.NET LMS solution with dedicated web, services, and data layers, Video.js live streaming, and an MQTT-powered real-time classroom chat with host moderation, polling, and participant management. Still live at tamland.ir.

  • Primary author of the ASP.NET LMS solution (2019–2021)
  • MQTT real-time class chat with host moderation & polls
  • Video.js live streaming — still in production at tamland.ir

  • C#
  • ASP.NET
  • JavaScript
  • MQTT
  • Video.js
  • SQL Server

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• SaaS & Platforms

  Doctor Chardi

  Telegram healthcare bot + doctor panel

  A healthcare communication platform (Asarad, 2017): patients talk to specialized doctors through a Telegram bot — test-result interpretation, medication questions, preliminary diagnoses — while doctors manage patient lists and respond through a dedicated web panel over a patient-management backend.

  • Telegram bot Q&A between patients and doctors
  • Doctor web panel + patient management system

  • Node.js
  • Telegram Bot API
  • .NET
  • SQL Server
  • MongoDB

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• Mobile

  Five.Community

  Enterprise retail community app — React Native

  A community platform delivered for Walmart as an enterprise retail engagement, spanning ~20 repositories. I authored both generations of the React Native app (1,200+ commits across the original MobX-State-Tree codebase and its rewrite, 2021–2022), integrating with enterprise APIs alongside the backend, ML-crawler, and infrastructure teams.

  • Primary author of the React Native app (iOS + Android)
  • Two codebase generations: MST original + rewrite
  • Enterprise API integration for Walmart

  • React Native
  • JavaScript
  • REST
  • Firebase

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• SaaS & Platforms

  Dobord — Gamified Cashback

  Asarad — gamification startup launch

  A gamified cashback platform architected for 1,000+ concurrent users, with MQTT pushing live cashback and leaderboard updates into an Angular front-end, and offer integrations with leading brands including Digikala and SnappFood.

  • 1,000+ concurrent users with live MQTT updates
  • Angular front-end over a .NET Core backend
  • Integrations with Digikala & SnappFood

  • .NET Core 2
  • C#
  • Angular
  • MQTT
  • SQL Server
  • PostgreSQL

  View details

• 

  High-Throughput Event Pipeline

  Kafka partitions into an Orleans actor cluster

  Event streams land on partitioned Kafka topics and fan out to a Microsoft Orleans cluster where every entity is a virtual actor holding its hot state in memory — no locks, no shared DB contention. Results write through to Redis for millisecond reads and SQL for durable history: 5M+ events a day at millisecond-level latency, scaled by adding partitions and silo nodes.

  • Event-Driven Architecture
  • Actor Model
  • Stream Processing
  • Partitioned Parallelism
• 

  Multi-Tenant IoT Environment

  MQTT uplink, rules engine, command downlink

  5,000+ devices authenticate with per-device credentials and publish over ACL-guarded MQTT topics — the topic tree is the API contract. Ingestion workers persist tenant-isolated telemetry, a rules engine raises alerts into per-tenant web and mobile clients, and a command service pushes control messages back down the same broker, so 2M+ daily events and the control path share one secured channel.

  • Publish/Subscribe
  • Multi-Tenancy
  • Topic ACL Security
  • Command & Telemetry Split
• 

  Where Each Layer Scales

  A different axis per layer, chosen deliberately

  The full scaling map of a production platform serving ~2k requests/sec: stateless API replicas multiply horizontally behind the load balancer, Redis grows vertically first and then splits by keyspace, Kafka scales by partition count chosen up front, and the relational core scales up with a tuned, cache-first read path — sharding stays the last resort, not the default.

  • Horizontal Scaling
  • Vertical Scaling
  • Cache-First Reads
  • Partitioning
• 

  Kubernetes Runtime Topology

  AKS namespaces, HPA, first-class telemetry

  Production and staging live in separate namespaces with their own config and secrets, deployed from the same manifests; traffic enters through the ingress controller to services fronting HPA-scaled deployments with liveness and readiness probes, and OpenTelemetry ships traces, metrics, and logs from every pod into Splunk and Elasticsearch dashboards — no SSH, no guesswork.

  • Container Orchestration
  • Horizontal Pod Autoscaling
  • Environment Isolation
  • Observability

All articles, with full-text search, are on the blog.