Alireza Rezapour

Backend Engineer

📍 Based in Mashhad, Iran

🎮 Gaming, Music, Walking

💼 Currently at Hamtapay

🛠 Always chasing better code

About Me

Backend engineer with 3+ years owning services from monolith-split to event-driven scale, plus production LLM/RAG work. Comfortable across Node.js, Go, Python and the messy edges in between (PostgreSQL tuning, Kong plugins, hybrid retrieval). Shipped wins: 90% fewer failed transactions, 99% read-load reduction, 70% MTTR cut, hallucination under 3% on a UK-lender RAG product.

Work Experience

Hamtapay

Aug 2025 – Present

Backend Engineer • Mashhad, Iran

Refactored payment-and-transfer engine core: tightened transaction isolation, optimized hot-path queries with targeted indexes, and tuned PgBouncer pooling — cutting transaction failures 90% and production incidents 30%.
Introduced read-side caching on hottest endpoints, dropping DB read load 99% (from 5,000+ req/s to under 20 req/s).
Migrated synchronous inter-service calls to RabbitMQ-based event-driven messaging, cutting cross-service network traffic 40% and decoupling failure domains.
Migrated analytical workloads from PostgreSQL to ClickHouse, halving dashboard p95 latency and offloading ~50% of PostgreSQL load.
Extended Kong API Gateway with custom Go plugins for auth, rate-limiting, and request shaping across production traffic.
Drove team-wide AI-assisted development practices (Cursor .rules, Claude CLAUDE.md, prompt patterns), cutting dev cycle time ~20% and lowering LLM token spend through better tool and agent usage.
Took ownership of legacy "What to Buy" top-4 crypto recommendation service: replaced underlying prediction LLM, added validation layer to filter low-confidence picks, improving recommendation quality.

Criterio (Sub-brand) — Lead Engineer

Built Criterio, an agentic RAG assistant over 50+ UK-lender lending-criteria documents with multi-turn context memory, follow-up question generation, and citation-grounded answers; replaced pure-embedding retrieval with AI-labeled chunk lookup over SQLite to fix recall on small corpora, holding LLM hallucination rate under 3% via strict prompting and citation grounding, with sub-60s response latency.
Shipped fully AI-driven daily blog auto-publishing one lending-criteria news article per day with generated imagery and cited sources. Stack: LangGraph, LangChain, Python, FastAPI, OpenAI / OpenRouter.

Part Software Group

Apr 2024 – Aug 2025

Backend Engineer • Mashhad, Iran

Resolved B2B-service outages (payments, auth, cron) via cross-team response and post-mortem ownership to prevent recurrence.
Migrated ~12 backend services from pm2-based deploys to a new internal Kubernetes-like platform, cutting deploy time from ~1 working day to minutes; onboarded team to the new workflow.
Designed and built B2B infrastructure services (payment, user, auth, cron) using hexagonal architecture and event-driven patterns to keep core domain logic decoupled and testable.
Diagnosed peak-time socket exhaustion across services, traced root cause to synchronous HTTP fan-out from cron jobs; authored proposal for message-queue architecture later adopted org-wide.
Authored RFCs on logging/observability, error-handling and API contracts, and service boundaries; standards adopted across multiple teams to reduce integration friction.
Acted as primary incident point of contact, leading critical-outage calls and cross-team meetings on behalf of tech lead.
Mentored junior engineers via code reviews, pair programming, and architectural guidance, raising team velocity and code-review quality.

Forvest

Aug 2023 – Apr 2024

Backend Developer • Mashhad, Iran

Contributed to monolith-to-microservices migration across core services, splitting domains and shortening deploy cycles.
Redesigned ~200-symbol crypto market-data ingestion service for higher fetch throughput, unblocking real-time AI analytics.
Adopted NATS for low-latency inter-service streaming, feeding downstream AI/analytics consumers.
Deployed KrakenD API Gateway for routing, rate-limiting, and horizontal scaling of backend endpoints.

Farajahan Hashtom

Jan 2023 – Aug 2023

Backend Developer • Mashhad, Iran

Built Node.js/Express REST endpoints with MongoDB persistence on backend team.
Implemented real-time WebSocket price-broadcast feature for live trading data.
Integrated BEP20/ERC20 wallet flow: per-user wallets on signup, on-chain balance polling via cron, deposit reconciliation to DB.

Projects

Criterio

Closed SourceLive

AI assistant for UK mortgage brokers: natural-language Q&A over 50+ lender criteria docs with multi-turn memory and cited answers. AI-labeled chunk retrieval, <3% hallucination, sub-60s latency. Daily auto-published lending-news blog with generated imagery.

PythonLangGraphLangChainFastAPIOpenAIOpenRouterSQLiteRAG

Sekebit

Closed SourceLive

Persian-language fintech: automated trading bot for global markets plus self-custody crypto wallet with fee-free internal transfers. Android app on Café Bazaar, Myket, APK.

TypeScriptTrading BotCrypto WalletReal-time StreamingMicroservicesAndroid