Python · FastAPI · AI · Senior Backend Engineer

Actively building with Python, FastAPI and agentic AI.

IBM RAG and Agentic AI Professional Certificate (Sep 2026) and a live AI-powered ERP Assistant in FastAPI and LangGraph — on top of 11+ years of backend architecture with PHP, Symfony and production ERP systems.

View selected work LinkedIn
Python FastAPI LangGraph RAG PHP Symfony MySQL ERP
11+ Years building systems
7+ Production systems
3 Industries served
Current focus

Python, FastAPI and AI on real ERP systems — certificate-backed and in production development.

  • Python / FastAPI APIs for AI assistants and agent workflows
  • RAG, LangGraph agents, semantic search and safe SQL over ERP data
  • IBM RAG and Agentic AI Professional Certificate (Sep 2026)
  • Backend architecture with PHP / Symfony and enterprise ERP
  • REST APIs, integrations and business process automation
  • Linux, production infrastructure and system modernization
What I do

More than code — software that solves real business problems.

I work across the full lifecycle of business applications — understanding the process, designing the architecture, building the system and keeping it running in production.

Python, FastAPI & AI

Actively building with Python and FastAPI — RAG systems, agentic workflows and LLM APIs wired into real business systems, backed by the IBM RAG and Agentic AI certificate.

Business Systems

Design and develop ERP, CRM and internal platforms that automate complex business processes and give management real operational visibility.

Backend & Architecture

Build reliable APIs, databases, integrations and asynchronous workflows designed for long-term production use and maintainability.

Infrastructure

Linux server setup, deployment, networking, firewall configuration, mail servers and automation — from development VPS to production environments.

Selected work

Current build: a Python / FastAPI AI assistant for ERP — plus production systems for operations and automation.

About me
AI Assistant Now Sep 2026 – Present

AI-powered ERP Assistant

Hybrid read-only AI assistant for an ERP system — still under active development — combining semantic search with validated SQL over MySQL AI views, exposed as a Gradio chat UI and a FastAPI HTTP API for ongoing improvement and client/ERP integration.

RAG Read-only SQL LangGraph FastAPI Semantic Search Docker
Stack: Python · LangChain · LangGraph · FastAPI · Gradio · MySQL · Qdrant · OpenAI · Google Gemini · sqlglot · Langfuse · Docker

Key highlights

  • LangGraph/ReAct agent (OpenAI or Gemini) that chooses semantic search for names and descriptions, or SQL for exact values, filters, aggregations and dates
  • Semantic index: MySQL ERP views to local multilingual-e5-small embeddings to Qdrant
  • SQL guard: sqlglot allows a single read-only SELECT on ai_view_* only, with a forced LIMIT, executed by a read-only MySQL user
  • FastAPI (chat, session history, session delete, health) and Gradio chat with model selection; conversation history in MySQL, keyed by session_id and shared by both
  • Docker Compose for FastAPI, Gradio, Qdrant and supporting services in local and staging environments
  • Optional Langfuse tracing for agent runs, retrieval and SQL
  • Actively iterating on agent tooling, retrieval quality and SQL safety based on real ERP usage
Incoming Tourism ERP

Incoming Tourism ERP

Operational ERP for an incoming tour operator, used by administrators, guides, drivers and clients, and processing thousands of clients a month. It covers shuttle tours, transfers, tourist services, fleet and guide planning, live margins, guide settlements, invoicing and payment tracking. Clients receive real-time updates on delays, issues and tour outlook via SMS, WhatsApp, Viber and email. Booking flows through Bokun and the operator’s websites. GetYourGuide, Viator and Civitatis payouts are reconciled from their files into client payments.

OTA Integration Guide Settlements Payment Tracking Invoicing Messaging Docker
Stack: PHP · Symfony · Doctrine · MySQL · Twig · JavaScript · Webpack · REST / webhooks · Docker
  • ERP for shuttle tours, private and shuttle transfers, tourist services, fleet and distributors, used by administrators, guides, drivers and clients. It processes thousands of clients a month, with a separate portal for guides and drivers.
  • Live order and transfer P&L, recalculated when clients, costs, vehicles, fuel or payments change, plus daily guide pricing from dated price lists and reporting orders and wallets that settle cash, commissions, overtime, bilingual fees and penalties.
  • Bokun as the booking hub (signed API sync, webhooks, product-rate mapping, shuttle auto-insert, cancellations), with extra Viator change detection for time and pax, and reservation ingest from the operator’s own websites.
  • Invoicing and payment tracking: invoice, credit, debit and proforma documents with unpaid, partial and paid status from recorded payments; client and supplier payments on tours and transfers; payout-file reconciliation for GetYourGuide, Viator and Civitatis (and the same importer for Stripe and Klook), matched by booking reference and posted as bank payments.
  • Client communication over SMS, WhatsApp, Viber and email — tour reminders, hour-change notices, Smart Guide links, arrival tracking, and real-time updates on delays, operational issues and weather or tour outlook.
  • Channel coverage includes a direct GetYourGuide intake, private-order creation from Bokun, Viber delivery, and Free Sofia Tour booking create and update.
  • Dockerized Symfony application, MySQL and background workers for consistent staging and deployment environments
Industrial ERP

ERP & Recycling Management Platform

Designed and architected an end-to-end ERP platform for recycling operations, from domain modeling and database architecture to integrations, deployment and production infrastructure — supporting approximately 70 users and operators.

Modular Monolith Hardware Integration GPS Forecasting Inventory Financial Workflows Docker
Stack: PHP 8 · Symfony 5.4 · MySQL · Python · JavaScript · Linux · REST APIs · Serial Port · GPS · Docker
  • Designed the complete system architecture as a modular monolith using Symfony, including domain structure, application workflows and database schema
  • Designed the domain model and data architecture supporting logistics, weighing, inventory, financial workflows and automated documentation
  • Integrated industrial weighing scales through a dedicated process communicating with local hardware, capturing real-time weight data into ERP and inventory workflows
  • Designed API-based communication between the PHP application and a Python forecasting module running on a dedicated local environment connected to the weighing system
  • Integrated external GPS services and license plate scanning into logistics workflows
  • Implemented background jobs, automated document generation, market pricing integration, role-based access, audit logging and data recovery workflows
  • Designed and implemented the deployment and infrastructure setup, including the production environment and release process
  • Docker for the PHP application and Python forecasting module to keep app and ML services aligned across environments
Operations Platform

Task Management & Operations Platform

Designed and architected a modular operations platform for a large law firm, covering task management, time tracking, project management, expenses, reporting and document workflows — built and maintained for approximately 40 users.

Time Tracking Project Management Reporting Role-based Access Document Workflows Docker
Stack: PHP 8 · Symfony 6 · MySQL · JavaScript · Linux · REST APIs · Docker
  • Designed the complete modular monolith architecture and database schema from the ground up
  • Designed role-based access control and permission models for employees, clients and external partners across shared projects
  • Built fast time-tracking workflows accessible from both desktop and mobile, allowing users to associate tracked time with specific projects
  • Designed reporting architecture covering time, projects/cases, project expenses and documents, with configurable XLS and PDF exports
  • Implemented business logic for project financial data and profitability calculations based on different business rules
  • Integrated external services for company data, currency exchange rates and accounting workflows
  • Dockerized Symfony application and MySQL for staging and production-like deployment workflows
Travel ERP & CRM

Travel ERP & CRM

Travel ERP and CRM system with RESTful API architecture and integrated payment gateway workflows for travel business operations.

ERP CRM REST APIs Payment Gateways Docker
Stack: Symfony 4.4 · Zend Framework 3 · PHP 7.3 · MySQL 5.6 · RESTful APIs · Payment Gateways · Docker
  • Built on Symfony 4.4 and Zend Framework 3 with a RESTful service layer
  • Integrated payment gateways for travel booking and financial workflows
  • Relational data model supporting CRM and ERP operations for travel services
  • Docker for the PHP application and MySQL to streamline local and deployment environments
Text Analysis Platform

Natural Language Tool

Text analysis system for advertising agencies to prevent ads from showing on unauthorized, obscene and negative sites — processing up to 50,000,000 requests per day across a distributed multi-server architecture.

High Volume Multi-server Web Crawler Text Analysis Admin Panel Docker
Stack: Python 3.7 · Java 8 · PHP 7.2 · MySQL 8 · Memcached · Selenium · ChromeDriver · Apache 2.4 · Linux (CentOS 7) · Docker
  • Distributed architecture with a primary server and four slave nodes sharing load across the platform
  • Administrative panel for domains, excluded selectors, negative words, user groups and reporting with daily database backups
  • AI modules for web crawling, link indexing and automated text analysis stored in the database
  • Production infrastructure including LAMP stack, mail server, SSL/TLS, firewall, Memcached and MySQL optimization
  • Docker for app and service components across the distributed multi-server nodes
How I think

Principles that guide every system I build.

01

Business first

Technology is only useful when it solves a real business problem. I start with the process and the people, not the framework.

02

Pragmatic architecture

I prefer simple, evolvable systems over theoretically perfect architectures that add complexity without business value.

03

Automation

Repetitive manual workflows should become reliable software processes. If a person does it the same way every day, it can be automated.

04

Production matters

A feature is not finished when it works locally. It needs deployment, monitoring, error handling, security and recovery.

From idea to production

I can own the full lifecycle of a business application.

Most developer portfolios show: "I write code." This one shows something different — I can take a complex operational problem and turn it into a working, deployed and maintained system.

Understand
Business process, people, pain points and priorities
→
Design
Data model, architecture and system boundaries
→
Build
Clean, maintainable and practical implementation
→
Integrate
APIs, hardware, third-party systems and workflows
→
Deploy
Linux infrastructure, SSL, mail, monitoring
→
Improve
Performance, reporting, user feedback and iteration
Technology

Python and AI first — stable PHP backend, practical frontend and production infrastructure.

Python & AI
Python FastAPI LangChain LangGraph RAG Qdrant OpenAI Google Gemini Gradio Langfuse
Backend
PHP Symfony Laminas REST APIs Doctrine Queues & Workers
Data
MySQL MariaDB PostgreSQL SQL Optimization Redis Memcached
Frontend
VueJS ReactJS NextJS JavaScript HTML5 CSS3
Infrastructure
Linux Apache Nginx Docker VPS Firewall SSL/TLS Mail Servers GitLab
Integrations
Serial / Hardware Devices GPS Tracking Barcode / QR Stock Exchange APIs Booking APIs (Bokun) OTA payouts (GetYourGuide, Viator, Civitatis) WhatsApp / SMS Email / Viber
ERP Platforms
Custom ERP Microsoft Dynamics 365 BC CRM Systems Reporting & Dashboards
Experience

11+ years delivering software that runs in production.

Jan 2018 – Nov 2026
Lead Software Engineer
DevScale.BG

Lead the architecture, development and technical delivery of custom ERP and business-critical software systems, working directly with clients from requirements through production and long-term evolution.

  • Actively building Python/FastAPI AI solutions for ERP — RAG, LangGraph agents and safe SQL over production data (AI-powered ERP Assistant)
  • Own technical architecture and make independent architectural and technology decisions
  • Design and develop complex backend systems and ERP platforms using PHP, Symfony and MySQL/MariaDB
  • Translate business requirements into system architecture, domain models, workflows, database structures and technical solutions
  • Work directly with clients on requirements, scope, technical estimates and project pricing
  • Own the full technical lifecycle from solution design and development to deployment, production support and continuous improvement
  • Design and maintain staging environments for release validation before production deployment
  • Built and maintain the deployment process used to promote tested applications to production
  • Take responsibility for production infrastructure, deployment reliability and troubleshooting
  • Design APIs and integrations connecting ERP systems with external services, business platforms and hardware
  • Lead technical decisions around database design, application structure, integrations, performance and maintainability
  • Modernize existing systems through refactoring, optimization and architectural improvements
  • Mentor and support developers, providing technical guidance and helping them grow within the team
  • Review changes and monitor development work to maintain technical consistency
Core technologies: Python, FastAPI, LangChain, LangGraph, PHP, Symfony, MySQL, MariaDB, REST APIs, Doctrine, JavaScript, Vue.js, Linux, Nginx/Apache, Docker, Git
Jul 2013 – Jan 2018
Software Engineer
Studio ITTI

Developed and maintained web-based business applications, backend systems and supporting infrastructure across a range of client and internal projects.

  • Designed and implemented backend functionality and business logic for web applications
  • Worked with relational databases, data models and application integrations
  • Developed and maintained custom business functionality based on client requirements and operational workflows
  • Contributed to system improvements, debugging, maintenance and ongoing feature development
  • Worked across backend and frontend components to deliver complete web applications
  • Supported database-related development and optimization
  • Collaborated directly on requirements, implementation and delivery of client projects
Core technologies: PHP, MySQL, JavaScript, HTML/CSS, Linux
View full experience on LinkedIn →
Certifications

Formal training that matches the work I am shipping now.

Sep 2026
IBM RAG and Agentic AI
IBM

Credential ID: KSMY4YW44SDX · Show credential

Education

Academic background in software and telecommunications engineering.

2015 – 2017
Master's Degree, Computer Software Engineering
New Bulgarian University
2011 – 2015
Bachelor's Degree, Telecommunications Engineering
Technical University of Sofia
About

Moving into Python, FastAPI and AI — with deep backend architecture behind it.

Senior Backend Engineer with 13+ years of experience designing and delivering ERP and business-critical systems with PHP, Symfony and MySQL, from domain modeling and integrations to deployment and production support. At DevScale.BG I lead architecture and delivery end to end, working directly with clients on requirements, estimates and long-term evolution of their systems.

I'm extending this foundation with Python, FastAPI and AI. I'm building an ERP Assistant that combines RAG and LangGraph agents with a validated read-only SQL layer over real ERP data, and I hold the IBM RAG and Agentic AI Professional Certificate (2026).

My technical experience includes

PHP / Symfony / Laminas Backend architecture and system design Enterprise ERP and CRM systems REST APIs and system integrations MySQL / MariaDB Python / FastAPI RAG / Agentic AI / LangGraph Business process automation Linux and production infrastructure JavaScript / Vue.js Performance optimization Legacy system modernization and refactoring

Throughout my career, I've worked on systems covering incoming tourism operations, production, inventory, warehouse management, logistics, billing, project management, reporting and operational workflows.

My approach is to understand the business domain first and then design software that fits the problem — choosing appropriate architecture, data models, integrations and technical solutions rather than simply implementing isolated features.

I'm comfortable working across the full lifecycle of a backend system:

  • understanding business and technical requirements
  • designing system architecture and data models
  • defining APIs and integrations
  • implementing core backend functionality
  • improving existing architecture and legacy systems
  • troubleshooting complex production issues
  • optimizing performance and reliability
  • working with infrastructure and deployment environments

I'm looking for a Senior Backend Engineer role where I can apply my ERP and architecture experience and bring Python and AI into real business platforms.

Get in touch LinkedIn
Open to opportunities

I'm looking for a Senior Backend Engineer role where I can apply my ERP and architecture experience and bring Python and AI into real business platforms.

Contact me LinkedIn