Hire the Best Regular Expressions Developers in Belgrade, RS

🚀 Delivered 16+ projects since 2019, AI integration since 2023. My clients get manual workflows replaced with automation and AI - up to 40% faster response, 20+ hours saved monthly. Glad to build yours next! 🔴 Backend Developer | Node.js | Python | TypeScript 🔴 Founder-led studio based in Belgrade, in-house team 🔴 12 years in IT consulting & business analysis 🔴 Thinking like a product owner, not just a coder 🔴 My clients return with new projects - that's how we measure quality CLICK MESSAGE to get a free mini-audit of your workflow 📩 My goal is simple: find what's eating your team's time and build the backend that replaces it - on time, on budget, with a 6-month warranty. 🎯 Need a Backend Developer who builds with Node.js, Python, and TypeScript? As a Backend Developer, I've built REST APIs, database architectures, automation backends, and data pipelines. Every Backend Developer project starts with discovery - we figure out what you actually need before code. Whether you need a Backend Developer for your API, a Python Developer for data pipelines, or a Node.js Developer for automation - you get a written spec, transparent budget, and weekly updates. WHAT I BUILD ➡️ BACKEND DEVELOPMENT As a Backend Developer, I build systems with Node.js, Python, and TypeScript. REST APIs, database design, authentication, webhooks, background jobs. Every Backend Developer project built for reliability. PostgreSQL, MongoDB, Docker, CI/CD. A Backend Developer who thinks like a product owner, not just a coder. ➡️ PYTHON DEVELOPMENT As a Python Developer, I build data pipelines, web scraping systems, ETL workflows, and automation backends. Selenium, Pandas, Google Sheets API. Every Python Developer project delivers structured output from messy inputs. Scheduled extraction, data processing, report generation. ➡️ NODE.JS DEVELOPMENT As a Node.js Developer, I build REST APIs, webhook handlers, automation backends, and SaaS platforms. Express, Koa, TypeScript. Every Node.js Developer project built with clean architecture and documentation. Payment integrations, multi-tenant systems, real-time processing. ➡️ AI INTEGRATION RAG systems, AI agents, GPT/Claude API - integrated into Node.js and Python backends. As a Backend Developer, I wire AI into your API. AI that answers from your data, never invents. Structured outputs, human-in-the-loop, anti-hallucination guardrails. ➡️ AUTOMATION Business process automation with Node.js and Python. Web scraping, data pipelines, report generation, scheduled tasks. Automation that replaces 10-20 hours of manual work per week. TECHNOLOGIES I USE: ➡️ BACKEND Node.js, Python, TypeScript, PostgreSQL, MongoDB, Docker, REST APIs, Webhooks, Koa, Express. Every Backend Developer tool needed for production systems. ➡️ AUTOMATION & SCRAPING Selenium, Playwright, Google Sheets API, Pandas, Apache POI, cron. Python and Node.js for data extraction and ETL pipelines. ➡️ AI & LLM OpenAI API, Claude API, RAG systems, AI agents, pgvector, prompt engineering. ➡️ DEPLOYMENT Docker, Nginx, CI/CD (GitHub Actions), VPS, Railway. DOMAINS & PRODUCTS I BUILD: SaaS backends, internal tools, admin panels, data pipelines, RAG chatbots, AI agents, workflow automation, web scraping platforms. My projects focus on measurable outcomes: 40% faster response times, 20+ hours saved monthly, 10+ hours saved weekly, zero lost leads. Technologies we bring to projects: Backend Developer, Node.js Developer, Python Developer, TypeScript Developer, API Developer, PostgreSQL Developer, MongoDB Developer, Docker Developer, AI Integration Developer, Automation Developer, Web Scraping Developer, Data Pipeline Developer, ETL Developer, Backend API Developer, Node.js Backend Developer, Python Backend Developer. MESSAGE me "BACKEND" and get a free mini-audit of your workflow 📩

I am a highly skilled Python developer with a robust background in retrieval-augmented generation (RAG), machine learning, and AI-driven solutions. My expertise spans building LangChain applications, managing Linux servers, and developing tailored ML workflows for complex problem-solving. I hold a degree in Information Security from the prestigious St. Petersburg State Transport University, where I gained a deep understanding of system integrity and formal verification techniques. Over the years, I have delivered successful projects in data scraping, API development, and scripting, utilizing frameworks like Django and libraries for data processing and analytics. Additionally, I have experience working on the frontend with Vue.js, enabling me to create dynamic and user-friendly interfaces for web applications. My recent work includes: Designing end-to-end ML pipelines for data optimization and real-time AI applications. Implementing scalable RAG frameworks for document and knowledge-based query solutions. Managing Linux server environments for efficient deployment and monitoring of production applications. Building robust APIs and integrating them seamlessly with various platforms. Developing frontend components and features using Vue.js to complement backend functionality. I am passionate about crafting innovative solutions for startups and established companies, providing top-tier performance while remaining flexible to evolving client needs. Let’s work together to bring your vision to life!

I Design Scalable Backend & AI Systems (Spring Boot, LLM Integration, ERP, Fintech) If you need more than just a developer — if you need someone who understands both your business and how to build the system behind it — we should talk. I design and build backend systems for ERP, production environments, and data-heavy platforms, with a focus on scalability, reliability, and real-world usage. I’m not here to just write code — I help you structure the system, avoid costly mistakes, and deliver something that actually works in production. With 10+ years in software engineering and a background in production systems and business processes, I bring more than coding skills. I’ve worked on systems where downtime costs money, bad architecture breaks operations, and “just ship it” is not an option. That’s why I focus on: System design over quick hacks Scalable backend architecture Clean, maintainable solutions that survive real usage I typically help clients with: ✔ Designing backend architecture for SaaS and ERP systems ✔ Building scalable APIs with Spring Boot (high-load ready) ✔ Multi-tenant systems and data isolation strategies ✔ Integrating AI/LLM into backend workflows (automation, document processing, decision support) ✔ Refactoring broken systems that don’t scale ✔ Connecting complex systems (payments, external APIs, legacy systems) Unlike most developers, I understand the business side behind the system: Production & manufacturing workflows ERP logic and operational constraints Financial and data-driven systems This allows me to translate business requirements into working systems without endless back-and-forth. Tech I use when it makes sense: Java, Spring Boot REST / Microservices architecture SQL (MySQL, PostgreSQL, MSSQL) Kafka / messaging systems Docker / containerized environments AI integration (LLMs, APIs, automation pipelin

I find the pricing and logic errors that quietly cost travel companies revenue — before they reach customers or decision systems. As the sole data-validation analyst on a travel loyalty-optimisation platform, I've independently QA'd a loyalty-and-pricing engine with 100,000+ rules, validate hundreds of fares daily, and build the calculation models that confirm an app's output matches real-world earning and pricing behaviour. WHO I HELP Travel-tech teams, loyalty platforms, OTAs and airline-programme tools that depend on large, fast-moving pricing and earning data they need to trust. WHAT I DO - Competitor price monitoring across multiple travel sites - Fare and award anomaly detection (Deal / Flash Deal / Phantom Fare classification) - Independent calculation models that verify airline status, earning and pricing logic - Large-dataset verification, QA workflows and continuous data-consistency testing - Python data pipelines: API ingestion → PostgreSQL → analytics → dashboard HOW I BUILD IT I design end-to-end pipelines that pull live fares from the Amadeus and Duffel APIs, store append-only price observations in PostgreSQL, classify deals against rolling baselines, and gate every alert through a QA verification step before export. The result: clean, trustworthy data instead of false signals. TOOLS Python (pandas, SQLAlchemy, pipelines, automation) · PostgreSQL · SQL · Google Sheets · Excel · Amadeus & Duffel APIs · Streamlit · Docker · ETL A recent client put it simply: "Stefan helped us set up and test our complex logic system with over 100,000 rules — no small task." If you have pricing or loyalty data you can't fully trust, tell me what's breaking and I'll tell you how I'd validate it.

Aleksei N. – Expert in Automation and Data Parsing | Python Developer Rate: $60/hr | Location: Belgrade, Serbia | Availability: 30+ hours/week Hello! I specialize in process automation, data parsing, and database management, with over 10 years of experience in the field. My mission is to help businesses streamline operations, reduce manual work, and leverage data effectively by implementing automated solutions. 🔧 Key Skills and Services I Offer: Data Parsing: Extracting data from websites, APIs, files, and databases of any complexity. Automation: Developing custom scripts and tools to automate repetitive tasks, saving time and resources. Database Management: Expertise in both relational (PostgreSQL, MySQL) and non-relational databases, optimizing performance and managing data structures. API Integration: Connecting business systems with external APIs for seamless data exchange and analytics. 🏆 Why Choose Me: Proven Expertise: 10+ years of experience in automation, data scraping, and backend solutions. Commitment to Quality: I deliver reliable solutions, meeting deadlines and exceeding expectations. Transparent Communication: I believe in regular updates and open communication throughout the project to ensure alignment with your goals. Long-term Collaboration: My focus is on building lasting partnerships and delivering consistent value. 📈 Examples of Completed Projects: Keyword Trends Crawler: Automated scraping of weekly trends from Google Play and the App Store for marketing optimization. Database Integration: API-based data collection and processing for business intelligence in real-time. Custom Automation Scripts: Automated report generation and notification systems to streamline business workflows.

I am a seasoned data extraction and automation specialist with over 20 years of experience in web scraping, data mining, back-end development, Big Data processing, AI/LLM integration, and intelligent workflow automation. My core expertise is Python-based scraping and data engineering. I work with Scrapy, Selenium, Playwright, Scrapy/Splash, APIs, reverse engineering, and custom data extraction pipelines designed to collect, process, clean, enrich, and deliver large volumes of data reliably. In recent years, I have also focused heavily on AI-assisted data processing and automation. I build solutions that use AI/LLMs to classify, normalize, summarize, deduplicate, validate, and enrich scraped or imported data. This allows clients not only to collect data, but also to transform raw information into structured, useful, and decision-ready datasets. My services include designing and developing scalable scraping systems, automated data pipelines, back-end services, and AI-powered workflows that can process both batch and real-time data streams. My areas of specialization include: Large-scale web scraping and data extraction using Python, Scrapy, Playwright, Selenium, and APIs. Business listings, Yellow Pages, company directories, and country-specific databases. Travel, accommodation, booking, and ticket reservation websites. Specialized online databases in real estate, legal, medical, financial, and professional services. Search engine data extraction from Google, Bing, Yahoo, and other platforms based on client-defined criteria. E-commerce platforms, product catalogs, pricing data, stock availability, and competitor monitoring. Financial sector data extraction, real-time market data collection, and data stream processing. Complex API scraping, undocumented API analysis, and structured data extraction. Mobile app data extraction and reverse engineering for Android and iOS. AI-assisted data cleaning, classification, normalization, enrichment, and deduplication. LLM-based automation for text processing, entity extraction, summarization, and insight generation. Automated workflows that combine scraping, databases, AI models, notifications, dashboards, and reporting. I can deliver data in CSV, Excel, JSON, SQL dumps, or integrate it directly into databases such as PostgreSQL, MySQL, MongoDB, or existing client systems. I also build automated pipelines that continuously collect, process, validate, and update data with minimal manual intervention. My goal is not only to extract data, but to help clients turn raw information into structured, reliable, and actionable assets. Whether you need a one-time scraping project, a scalable data pipeline, AI-powered data processing, or full automation of a business workflow, I can design and deliver a robust solution tailored to your needs. I look forward to helping you use data, automation, and AI to improve your processes, support better decisions, and achieve your project goals.