Alexander Kostas

Backend & AI Automation Engineer

Production-ready systems • API Integration • AI/LLM • Reliability

What Is This?

This is a live, working portfolio — not mockups or screenshots. Each demo below is a fully functional application running on my server right now. Try them out to see my coding style, architecture decisions, and attention to production details like security, error handling, and user experience.

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Rate-limited & secure — safe to explore

Real APIs you can call programmatically

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Full API documentation available

Interactive Demos

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AI Document Q&A

Upload a PDF or text file, then ask questions about its contents. The AI reads and understands your document to provide accurate answers.

How to use:

  1. Upload any PDF or TXT file (max 5MB)
  2. Ask a question about the content
  3. Get an AI-powered answer
FastAPI Claude AI RAG
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Webhook Automation

Simulate sending webhooks and watch them get processed in real-time. See queue management, success/failure rates, and processing history.

How to use:

  1. Select an event type (e.g., user.created)
  2. Edit the JSON payload if desired
  3. Click "Send" and watch it process
API Integration Queues Automation
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System Dashboard

Watch live system metrics update in real-time via WebSocket. See CPU, memory, request rates, and alerts as they happen.

How to use:

  1. Open the dashboard
  2. Watch metrics update every 2 seconds
  3. See charts build in real-time
WebSocket Real-time Monitoring
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What I Can Build For You

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API Integrations

Connect your systems to third-party APIs, handle webhooks, sync data between platforms

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AI/LLM Applications

Build AI-powered features using Claude, GPT, or other models — chatbots, document analysis, automation

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Backend Systems

REST APIs, database design, authentication, background jobs, caching

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Dashboards & Monitoring

Real-time dashboards, alerting systems, data visualization, admin panels

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Automation & Scripts

Automate repetitive tasks, data pipelines, scheduled jobs, web scraping

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Production Hardening

Security audits, rate limiting, error handling, logging, deployment

Technical Skills

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Python

FastAPI, Django

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AI/LLM

Claude, OpenAI, RAG

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API Integration

REST, Webhooks

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Databases

PostgreSQL, Redis

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Linux

Server Admin

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Automation

CI/CD, Scripts

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Node.js

Express, APIs

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Cloud

AWS, GCP, VPS

Built with FastAPI, Python, and Claude AI

Upwork API Docs