Available for opportunities

Building Secure, Scalable Systems That Actually Work

Full-stack engineer focused on APIs, cloud systems, and real-world applications. I build things that handle production load.

Proof at a GlanceRegulaPilot
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Featured Work

Systems built to solve real problems

View all projects
Backend01

LendGraph

Private credit infrastructure for automated loan management and investor intelligence

KotlinSpring BootPostgreSQLReact+3
Backend02

Fitness Tracking API

Production-grade REST API with RBAC, HATEOAS, and ETag caching

Node.jsKoaMySQLJWT+3
AI / ML03

RegulaPilot

AI-powered compliance workflow system with a real backend and structured LLM pipeline

ReactNext.jsTypeScriptTailwind+5
04

Café Digital Growth & Operations Platform

End-to-end system for customer engagement, retention, and business operations

ReactNode.jsExpress/KoaMySQL+3
System Design

Explore the Architecture

Step inside the systems behind my projects — from user action to backend response.

Click any node to explore its role in the system

RESTful API with JWT authentication, RBAC middleware, and a layered backend architecture built on Koa.js and MySQL.

Client

Vue SPA Client

Single-page application that consumes the REST API. Sends Bearer tokens with every authenticated request and handles token-refresh logic on 401 responses.

Request Trace
$GET /api/v1/workouts
Bearer token received
JWT signature verified
workouts:read scope confirmed
Ownership rule applied
Service layer queried MySQL
ETag hash generated
200 OK returned
Key Decisions
  • RESTful API following Richardson Maturity Model Level 3
  • JWT authentication with role and scope-based access control
  • ETag support for efficient conditional GET requests
  • Zod validation and strict layered backend architecture
  • Comprehensive endpoint testing with Jest and Supertest

Featured Case Study

Engineering in depth

BackendREST API · Node.js · Koa

LendGraph

Private credit infrastructure for automated loan management and investor intelligence

The Problem

Modern fitness applications demand APIs that go beyond basic CRUD — handling complex user hierarchies, enforcing fine-grained access control, and remaining self-documenting at runtime without a separate documentation step.

Architecture Layers

1

Presentation LayerReact/Next.js dashboard with professional-grade data viz (Recharts) and real-time status indicators.

2

AI Extraction LayerNext.js API routes integrated with LLMs to parse PDF facility agreements into structured JSON objects.

3

API & Service LayerKotlin Spring Boot services handling complex financial math (IRR, WAC) and business logic.

4

Data Access LayerJPA/Hibernate with Type-safe repositories ensuring strict relational integrity for loan-to-investor mappings.

5

Persistence LayerPostgreSQL database with custom constraints to prevent invalid financial states (e.g., negative interest).

Key Engineering Decisions

  • JWT with refresh token rotation — zero long-lived secrets in circulation
  • RBAC permission matrix — O(1) authorization checks at every endpoint
  • ETag caching — ~60% bandwidth reduction on read-heavy workloads
  • HATEOAS responses — API is self-documenting at runtime
  • Integration test suite — real database, real assertions, no mocks at data layer

Tech Stack

KotlinSpring BootPostgreSQLReactTypeScriptNext.jsOpenAI API

Read the full case study

Architecture, security, testing, and outcomes

Expertise

Skills & Technologies

Backend

Node.jsKoa.jsREST APIsMySQLJWT AuthRBACHATEOAS

Frontend

ReactNext.jsVue.jsTypeScriptTailwind CSS

Mobile

.NET MAUIMVVMC#Cross-PlatformOffline-First

AI / ML

PythonPyTorchCNNsVideo ClassificationCUDA

Cloud & Infra

SupabaseDockerPostgreSQLOpenAPIVercel

Tools

GitJestPostmanVS CodeSQLite
Infrastructure Map

Systems Network

Explore how my projects connect across backend APIs, cloud platforms, AI pipelines, mobile architecture, and product systems.

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Fitness Tracking API

Backend / API

A production-style REST API for fitness and wellness tracking, designed with secure authentication, scoped authorisation, layered architecture, OpenAPI documentation, and automated testing.

Tech Stack
Node.jsKoaMySQLJWTRBACOpenAPIJest
Engineering Focus
  • Richardson Maturity Model Level 3 REST design
  • JWT authentication and role/scope-based access control
  • ETag caching and conditional GET support
  • Zod validation and layered services
  • Comprehensive endpoint testing

About

The engineer
behind the work

I build systems with architecture in mind first — thinking about security, scalability, and maintainability before a single line is written.

My focus spans the full stack: from designing secure REST APIs with RBAC and HATEOAS, to building cross-platform mobile apps with offline-first architecture, to training deep learning models for video classification. The common thread is engineering rigour and a preference for systems that actually hold up under production conditions.

I write code to be read by the next engineer — tested, documented at the right level, and structured so that change doesn't require archaeological excavation.

Engineering Principles

Architecture first

Design the system before writing the code.

Security by default

Baked in from day one — not retrofitted.

Test what matters

Integration over mocks; confidence over coverage theatre.

Clean over clever

The next engineer should thank you, not curse you.

3+
Production-grade projects
5+
Core technologies
L3
REST maturity achieved
0
Known OWASP vulnerabilities

Ready to build

Let's build something impactful

I'm currently available for freelance work, contract roles, and full-time positions. If you have a technical challenge worth solving, let's talk.

Contact

Start a conversation

Have a project in mind, a role to fill, or just want to connect? Reach out directly.

Source Code
github.com/Parsa13831383
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