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Behdad Sayadi

Software Engineer · Python & Backend Systems

Gorgan, Iran · Open to freelance & remote backend work

Backend-focused Software Engineer with 4+ years of experience building production-ready systems with Python, Django, PostgreSQL, Redis, and Celery. Experienced in backend architecture, REST and GraphQL API design, database design, asynchronous processing, and authentication. Comfortable owning systems end-to-end, from requirements and architecture through implementation and deployment, while leading multidisciplinary engineering teams.

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skills

Technical skills

Languages

Python SQL C++ HTML/CSS JavaScript/TypeScript

Backend

Django Django REST Framework FastAPI SQLAlchemy GraphQL Graphene-Django

Data

PostgreSQL MySQL MongoDB SQLite Redis

Infrastructure

Docker Docker Compose Linux Nginx Gunicorn

Async Systems

Celery Celery Beat Background Processing Task Scheduling

Engineering

REST APIs Database Design ORM Optimization Performance Optimization Authentication Authorization RBAC Code Review

Security

XSS CSRF SQL Injection SSRF SSTI JWT Access Control

Tools

Git/GitHub OpenCV Data Analysis Bash

experience

Experience

Backend Developer · Freelance / Contract 2022 — Present · Remote

Python · Django · DRF · FastAPI · PostgreSQL · Redis · Docker

Designed and delivered production-ready backend systems for multiple clients and industries, including four projects delivered through Developeria during 2024–2025.
Architected and implemented secure REST APIs with Django REST Framework, covering authentication, permissions, validation, filtering, pagination, and role-based access control.
Designed relational models and improved database performance through indexing, query optimization, and ORM-level profiling.
Built asynchronous workflows with Celery and Redis for OTP authentication, background processing, and scheduled tasks.
Developed GraphQL APIs alongside REST-based services, adapting API architecture to product requirements.
Worked directly with clients and product teams to translate requirements into technical architecture, implementation plans, and production-ready systems.

Founder & Engineering Lead · Kaizen Dev Team 2024 — Present · Hybrid

Technical Leadership · Architecture · Code Review · Engineering Workflow

Founded and led a multidisciplinary software development team delivering web-based products from initial requirements through implementation.
Defined backend architecture, engineering standards, repository structure, development workflows, and technical conventions.
Reviewed implementations for maintainability, security, performance, consistency, and adherence to architectural standards.
Coordinated backend and frontend development and translated product requirements into technical execution across the team.

projects

Selected projects

Aphra · Barber Discovery & Reservation Platform 2026 — Present

DRF · PostgreSQL · Celery · Redis · Docker

Founded and built Aphra, a SaaS platform for discovering barbers, exploring services, and booking appointments.
Owned the product's backend architecture and core data model, covering customers, barbers, salons, services, appointments, availability, media, authentication, and role-based access control.
Designed and implemented the REST API layer with filtering, pagination, validation, permissions, media uploads, and reservation workflows.
Designed the scheduling and availability system, implementing business-rule validation and safeguards against conflicting reservations.
Implemented asynchronous infrastructure with Celery and Redis for OTP authentication, notifications, and background processing.
Led product development end-to-end, contributing to backend, frontend, and UI/UX decisions while turning product requirements into a production-ready platform.

University System · GraphQL Backend 2024 — 2026

Django · GraphQL (Graphene-Django) · PostgreSQL · Redis · Celery · Docker

Built a Django backend for a university's academic workflows — course registration, add/drop correction, grade reconsideration, emergency withdrawal, semester withdrawal, and deferment — exposed entirely through a single GraphQL API (Graphene-Django), with no REST layer.
Enforced real registration business rules in the resolvers: prerequisites already passed, no duplicate courses, course capacity, GPA-based unit limits, and no schedule or exam clashes — all scoped to the student's own major.
Implemented JWT authentication with logout token blacklisting (django-graphql-jwt plus a custom check on every request), and role-based access scoped by faculty for staff, assistants, professors, and students.
Added Redis-backed caching for query resolvers and Celery for background email (password resets, course-approval notices), running behind PostgreSQL in a four-container Docker Compose setup.

Library Management CLI 2025 — 2026

Python · MySQL · bcrypt

Built a terminal-based library system in Python and MySQL covering the full lending lifecycle: book inventory, member accounts, borrowing, returns, and fines.
Enforced borrowing rules in the data layer: a 14-day loan period, a 3-active-loan cap per member, a block on borrowing once a member has 2 unpaid fines, and an automatic $25/day fine once a return passes a 3-day grace period.
Used a MySQL trigger to guarantee only one admin account can ever exist — enforced at the database level, not just in application code — alongside bcrypt-hashed passwords and per-model validation that blocks deleting any record still referenced elsewhere (e.g. an author with books).
Structured the codebase into separate modules for CLI menus, data models, and authentication, with a dedicated test suite for every model and a Faker-based seed script that fills the database with realistic sample data, including some intentionally overdue loans.

achievements

Competitive programming & achievements

certifications

Certifications

education

Education

Undergraduate Studies · Golestan University 2 semesters

Completed two semesters before choosing to leave and continue building a software engineering career independently, favoring hands-on production work over the remaining coursework.

languages

Languages

Persian · Native

English · Professional Working Proficiency

contact

Get in touch

Open to freelance projects, backend roles, and technical collaboration.

AFrenchWrench@gmail.com +98 919 544 9241 Gorgan, Iran