# LogicLoopTech

> Practical backend engineering from production: FastAPI, AI agents, RAG systems, API architecture, and data pipelines. Written by Ayush Kaushik.

LogicLoopTech is the engineering blog and consulting site of Ayush Kaushik, a backend and AI engineer. Articles are written from production experience: FastAPI, Python, backend architecture, AI agents, and RAG/LLM systems.

## Articles

- [RAG Chunking Best Practices for Production Systems](https://www.logiclooptech.dev/rag-chunking-best-practices-for-production-systems/): Learn proven RAG chunking best practices for LLMs - optimal size, overlap, tabular data, evaluation, and tools - based on real production experience.
- [Python Message Queue Between Processes: IPC Options for FastAPI Workers](https://www.logiclooptech.dev/python-message-queue-between-processes-ipc-options-for-fastapi-workers/): Learn how to implement a python message queue between processes using multiprocessing.Queue, pipes, and shared memory, with FastAPI integration and performance trade-offs.
- [Redis caching in FastAPI: practical setup and pitfalls](https://www.logiclooptech.dev/redis-caching-in-fastapi-practical-setup-and-pitfalls-1/): Learn how to set up Redis caching in FastAPI for sessions and API results, avoid common pitfalls, and monitor performance in production.
- [Vibe Coding vs Agentic Coding: When to Use Which](https://www.logiclooptech.dev/vibe-coding-vs-agentic-coding-when-to-use-which/): Discover the differences between vibe coding and agentic coding, how they affect FastAPI AI projects, and which workflow fits your production needs.
- [Microservices Python Django: Practical Setup & Scaling](https://www.logiclooptech.dev/microservices-python-django-practical-setup-scaling/): Learn to build, containerize, and scale microservices python django apps with Django Rest Framework, Docker, and Kubernetes using inter-service patterns.
- [Bolt.new Python Backend: FastAPI from Zero to Production](https://www.logiclooptech.dev/bolt-new-python-backend-fastapi-from-zero-to-production/): Learn how to scaffold, connect async databases, and deploy a bolt new python backend using FastAPI, with code, pitfalls, and cost tips for indie builders.
- [Why ai generated code cannot be copyrighted and what to do](https://www.logiclooptech.dev/why-ai-generated-code-cannot-be-copyrighted-and-what-to-do/): Find out why ai generated code cannot be copyrighted, how to license snippets, and keep your IP safe when building AI-assisted apps. with open-source tips.
- [How to Fix Claude Code Error 529 in Production](https://www.logiclooptech.dev/how-to-fix-claude-code-error-529-in-production/): Learn why Claude code error 529 happens, how to debug it, and practical steps to prevent it in your AI-powered backend.
- [Hybrid Search RAG Implementation: A Practical Guide](https://www.logiclooptech.dev/hybrid-search-rag-implementation-a-practical-guide/): Build a hybrid search RAG implementation using LangChain and a vector store, with keyword fallback, and learn architecture, tuning, and production lessons.
- [Free AI App Builder with Backend: FastAPI Microservice Guide](https://www.logiclooptech.dev/free-ai-app-builder-with-backend-fastapi-microservice-guide/): Learn how to use a free AI app builder with backend to spin up a FastAPI microservice, avoid common pitfalls, and plan a smooth move to production.
- [Model Context Protocol Examples: How to Run MCP with FastAPI](https://www.logiclooptech.dev/model-context-protocol-examples-how-to-run-mcp-with-fastapi/): Learn practical model context protocol examples, set up MCP with Docker, call it from Python, and embed it in FastAPI for production-grade AI services.
- [FastAPI Rate Limiting: Practical Guide for Production](https://www.logiclooptech.dev/fastapi-rate-limiting-practical-guide-for-production/): Learn how to add fastapi rate limiting with custom middleware, Redis or libraries, and get tips for testing and production monitoring in real-world APIs.
- [How to Fix the copilot error code rate_limited in Production](https://www.logiclooptech.dev/how-to-fix-the-copilot-error-code-rate-limited-in-production/): Learn why the copilot error code rate_limited shows up, how to log it, add exponential backoff, adjust quotas, and fall back to local LLMs with Python.
- [Using Cursor AI Code Tracking API with FastAPI](https://www.logiclooptech.dev/using-cursor-ai-code-tracking-api-with-fastapi/): Authenticate, call, and store results from the Cursor AI Code Tracking API in FastAPI, using PostgreSQL or Redis, with security built in.
- [FastAPI Testing With Pytest: Practical Patterns](https://www.logiclooptech.dev/fastapi-testing-with-pytest-practical-patterns-for-reliable-code/): Learn how to set up pytest for FastAPI, use TestClient for sync and async routes, override dependencies, test auth, and manage DB fixtures in production.
- [Cursor AI code editor tutorial: setup, tips, and CI/CD](https://www.logiclooptech.dev/cursor-ai-code-editor-tutorial-setup-tips-and-ci-cd/): A step-by-step Cursor AI code editor tutorial: install it, wire it into FastAPI, and add linting, security checks, and CI/CD.
- [RAG pipeline diagram: design, build, and scale](https://www.logiclooptech.dev/rag-pipeline-diagram-design-build-and-scale/): Learn how to design a rag pipeline diagram, build each component with FastAPI, integrate vector stores and LLMs, and monitor it in production.
- [Building an ai agent python langchain with FastAPI](https://www.logiclooptech.dev/building-an-ai-agent-python-langchain-with-fastapi/): Learn how to build an ai agent python langchain, hook it into FastAPI, add memory and tool use, then deploy it with scaling and cost awareness.
- [Choosing a python message queue library for production](https://www.logiclooptech.dev/choosing-a-python-message-queue-library-for-production/): Find the right python message queue library for production. Compare Celery, RQ, Dramatiq, Kombu, and see a simple asyncio-Redis example monitoring tips.
- [ai generated code platform security checklist](https://www.logiclooptech.dev/ai-generated-code-platform-security-checklist/): Learn a practical checklist for ai generated code platform security, covering threat modeling, prompt injection, sandboxing, compliance, and monitoring.
- [Kafka Python Tutorial: From Docker to FastAPI](https://www.logiclooptech.dev/kafka-python-tutorial-from-docker-to-fastapi/): A hands-on kafka python tutorial: run a broker with Docker, produce and consume asynchronously, and wire it into FastAPI background work.
- [Redis caching in FastAPI: practical setup and pitfalls](https://www.logiclooptech.dev/redis-caching-in-fastapi-practical-setup-and-pitfalls/): Learn how to add redis caching in fastapi, covering installation, async client integration, decorators, invalidation, Docker deployment, and monitoring.
- [Fixing AI Generated Code Quality Issues in Production](https://www.logiclooptech.dev/fixing-ai-generated-code-quality-issues-in-production/): Learn how to spot and fix AI generated code quality issues with automated tests, linting, CI gates, and practical refactoring tips for FastAPI backends.
- [Fixing an AI Generated Code Vulnerabilities Report](https://www.logiclooptech.dev/fixing-an-ai-generated-code-vulnerabilities-report/): Learn why AI generated code carries security flaws, and how to turn a vulnerabilities report into a reliable CI/CD guardrail for FastAPI.
- [RAG evaluation using ragas: a practical guide](https://www.logiclooptech.dev/rag-evaluation-using-ragas-a-practical-guide/): Learn rag evaluation using ragas in Python: install, run metrics on a sample pipeline, interpret scores, and automate checks in CI/CD for production.
- [How to build AI agent for stock analysis with FastAPI](https://www.logiclooptech.dev/how-to-build-ai-agent-for-stock-analysis-with-fastapi/): Learn step-by-step how to build an AI agent for stock analysis, from data sources to backtesting and automated FastAPI deployment, in production.
- [Comparing AI Agents Python Library Options for Production](https://www.logiclooptech.dev/comparing-ai-agents-python-library-options-for-production/): Compare the top AI agents python library options: LangChain, CrewAI, and LlamaIndex, and see how to embed one in FastAPI for production.
- [Event Driven Architecture vs Microservices: Which to Use](https://www.logiclooptech.dev/event-driven-architecture-vs-microservices-when-to-use-which/): I compare event driven architecture vs microservices, outline trade-offs, give Python code, and explain when each pattern is the right fit for production.
- [AI agent python ollama: Build, Test, Deploy with FastAPI](https://www.logiclooptech.dev/ai-agent-python-ollama-build-test-deploy-with-fastapi/): Learn how to run an AI agent in Python with Ollama, from local installation to FastAPI integration, testing, and production scaling, using code examples.
- [AI Generated Code Detection: Practical Guide for Builders](https://www.logiclooptech.dev/ai-generated-code-detection-practical-guide-for-builders/): Learn how to reliably detect AI-generated code in CI/CD, spot hidden security bugs, and navigate legal risks before they break production.
- [Building microservices python fastapi: design to production](https://www.logiclooptech.dev/building-microservices-python-fastapi-design-to-production/): Build microservices python fastapi from design to production, covering REST/gRPC choices, RabbitMQ/Kafka queues, Docker/K8s deployment, testing and security.
- [Using the OpenAI Agents SDK for Python: A Practical Guide](https://www.logiclooptech.dev/using-the-openai-agents-sdk-for-python-a-practical-guide/): Learn to install the OpenAI Agents SDK for Python, build agents that use tools, manage memory, add custom functions, and scale with FastAPI or serverless.
- [Practical RAG chunking strategies for reliable RAG pipelines](https://www.logiclooptech.dev/practical-rag-chunking-strategies-for-reliable-rag-pipelines/): Learn effective RAG chunking strategies, choose optimal chunk sizes, and evaluate chunk quality with Python tools like LangChain, LlamaIndex, and RAGAS.
- [Building a Robust RAG Pipeline Architecture for Production](https://www.logiclooptech.dev/building-a-robust-rag-pipeline-architecture-for-production/): Learn how to design, evaluate, and scale a production-grade RAG pipeline architecture with FastAPI, LangChain, and hybrid vector stores.
- [FastAPI WebSockets: Production-Ready Setup and Scaling](https://www.logiclooptech.dev/fastapi-websockets-production-ready-setup-and-scaling/): Learn how to build, secure, and scale fastapi websockets, covering basic endpoints, lifecycle handling, auth, broadcasting, and Redis-backed scaling.
- [How to Build AI Agents from Scratch with FastAPI](https://www.logiclooptech.dev/how-to-build-ai-agents-from-scratch-with-fastapi/): Learn how to build AI agents from scratch: set up Python, pick a framework, design the architecture, add memory, and deploy with FastAPI.
- [FastAPI asyncpg: Fast Async PostgreSQL Access](https://www.logiclooptech.dev/supercharge-your-api-fastapi-asyncpg-integration-for-high-performance-postgresql/): Learn how to combine FastAPI with asyncpg for fast, async PostgreSQL queries. Includes pooling, SQLAlchemy 2.0, transactions, and production tuning.
- [FastAPI Deployment on Render: Docker, CI/CD, Scaling](https://www.logiclooptech.dev/mastering-fastapi-deployment-on-render-from-docker-to-ci-cd-scaling-cost-effecti/): Learn step-by-step fastapi deployment on render with Docker, environment config, GitHub Actions CI/CD, scaling strategies, and monitoring tricks.
- [FastAPI Async Logging: Structured and Rotating Logs](https://www.logiclooptech.dev/mastering-fastapi-async-logging-structured-rotating-and-worker-ready-logs-for-hi/): Set up fastapi async logging with structlog and loguru, covering background tasks, websockets, Uvicorn and Gunicorn, and log rotation.
- [FastAPI Async vs Sync: Benchmarks and When to Use Each](https://www.logiclooptech.dev/fastapi-async-vs-sync-when-to-use-each-benchmarks-and-real-world-tips/): Discover the practical differences between fastapi async vs sync, how to choose the right endpoint type, benchmark results, pitfalls, and testing strategies.
- [FastAPI Error Handling Best Practices: A Hands-On Guide](https://www.logiclooptech.dev/mastering-fastapi-error-handling-best-practices-a-hands-on-guide/): Discover fastapi error handling best practices with custom exception handlers, middleware logging, validation strategies, and TestClient testing.
- [FastAPI background tasks poll APIs, create PDFs, send email](https://www.logiclooptech.dev/mastering-fastapi-background-tasks-real-world-patterns-testing-and-when-to-reach/): Discover how to use FastAPI background tasks to poll external APIs, generate PDFs and send emails with aiosmtplib, and know when to move to Celery.
- [FastAPI Deployment on Railway: Docker to CI/CD](https://www.logiclooptech.dev/mastering-fastapi-deployment-on-railway-from-docker-to-ci-cd/): Learn step-by-step fastapi deployment on railway with Docker, Uvicorn workers, PostgreSQL, migrations, and GitHub Actions CI/CD in a practical guide.
- [Welcome to LogicLoopTech](https://www.logiclooptech.dev/welcome/): A backend engineering blog on AI, RAG, and FastAPI, covering the real problems engineers hit running services in production.
- [FastAPI SQLAlchemy Session Leaks: Diagnose and Fix](https://www.logiclooptech.dev/fastapi-session-leak-detection-sqlalchemy-long-running/): Learn how to detect and fix FastAPI session leaks. A deep dive into SQLAlchemy connection pooling, long-running sessions, and production monitoring.
- [FastAPI Session Leak Detection: Find and Fix Them](https://www.logiclooptech.dev/fastapi-session-leak-detection-how-to-find-and-fix-long-running-sqlalchemy-sessions-in-production/): Seeing QueuePool errors or rising DB latency in FastAPI? Learn how to detect session leaks and fix long-running SQLAlchemy sessions in production.
- [Why Your FastAPI App Works Locally But Fails in Production](https://www.logiclooptech.dev/why-your-fastapi-app-works-locally-but-fails-in-p/): FastAPI works locally but fails in production? The five usual causes: Uvicorn workers, QueuePool limits, event loop blocking, and Docker CPU limits.
- [Uvicorn Health Checks Fail Under Load - Fix the Issue](https://www.logiclooptech.dev/uvicorn-health-check-failure-kubernetes-fix/): Learn why your Uvicorn health check times out when a CPU-intensive task blocks the event loop, and get a step-by-step fix to keep FastAPI pods healthy.
- [FastAPI in Production: Docker, Workers, and Scaling](https://www.logiclooptech.dev/fastapi-in-production-the-complete-deployment-guide-docker-workers-scaling-and-best-practices/): Deploy FastAPI the right way. Learn production architecture, Gunicorn vs Uvicorn, worker tuning, database pooling, Docker best practices, and scaling.
- [How Many Uvicorn Workers Do You Actually Need?](https://www.logiclooptech.dev/how-many-uvicorn-workers-do-you-actually-need-fastapi-performance-guide/): Stop guessing your worker count. Learn the (2 x CPU) + 1 formula, avoid the Docker CPU trap, and optimize FastAPI concurrency for production.
- [Why FastAPI Apps Slow Down: Low CPU, High Latency](https://www.logiclooptech.dev/why-fastapi-apps-slow-down-over-time-low-cpu-high-latency-explained/): Why FastAPI apps slow down over time: how session leaks and blocking code cause high latency while CPU stays low, and how to fix it for good.
- [Fix QueuePool Limit Reached: FastAPI Connection Leaks](https://www.logiclooptech.dev/fixing-queuepool-limit-reached-debugging-db-connection-leaks-in-fastapi/): FastAPI apps often fail in production due to silent database connection leaks. Learn why QueuePool errors happen and how to fix them correctly.
- [FastAPI Lifespan: Replace Deprecated @app.on_event Startup](https://www.logiclooptech.dev/fastapi-lifespan-vs-startup-events/): Learn to replace the deprecated @app.on_event startup with FastAPI's lifespan manager, so your async Motor client connects and shuts down cleanly.
- [FastAPI vs Flask 2026: Impact of Flask 3.1 Release](https://www.logiclooptech.dev/fastapi-vs-flask-in-2026-is-flask-finally-dead/): Discover how Flask 3.1’s release and new Flask-Cors version affect performance, async support, and developer experience compared to FastAPI in 2026.
- [Fix: AsyncSession Has No Attribute 'query' (SQLAlchemy 2.0)](https://www.logiclooptech.dev/asyncsession-has-no-attribute-query-in-sqlalchemy-20-fastapi-fix/): Hit AttributeError: AsyncSession object has no attribute query after upgrading to SQLAlchemy 2.0? Here is the select() syntax that fixes it in FastAPI.
- [How to Fix SQLAlchemy MissingGreenlet Error in FastAPI Async](https://www.logiclooptech.dev/fixing-sqlalchemy-missinggreenlet-error-in-fastapi-async-explained/): Learn why the 'greenlet_spawn has not been called' error occurs in async SQLAlchemy with FastAPI and get step-by-step code to fix it using selectinload.
- [CI/CD for Google Cloud Run with GitHub Actions](https://www.logiclooptech.dev/automating-production-a-cicd-pipeline-for-google-cloud-run-with-github-actions/): Automate your deployment. A step-by-step tutorial on building a continuous delivery pipeline for Dockerized apps on Google Cloud Run using GitHub Actions.
- [Deploy FastAPI to Google Cloud Run With Docker](https://www.logiclooptech.dev/serverless-python-deploying-fastapi-to-google-cloud-run-with-docker/): Learn how to containerize your Python API with Docker and deploy it to Google Cloud Run (Serverless). A step-by-step guide for production-ready deployment.
- [Fix AsyncSession Errors in FastAPI (SQLAlchemy 2.0 Guide)](https://www.logiclooptech.dev/modern-backend-building-high-performance-async-apis-with-fastapi-and-sqlalchemy-20/): Build high-performance async APIs with FastAPI and SQLAlchemy 2.0: architecture, async sessions, and the pitfalls that break production systems.
- [How to Send Firebase Push Notifications with Python](https://www.logiclooptech.dev/send-fcm-notifications-python/): Send FCM push notifications from Python with the Firebase Admin SDK: setup, working code examples, and how to test your notification integration.
- [Schedule Python Scripts on Google Cloud (Serverless)](https://www.logiclooptech.dev/serverless-automation-scheduling-python-scripts-with-google-cloud/): Schedule Python scripts serverlessly with Google Cloud Run and Cloud Scheduler. A practical guide to replacing local cron jobs in production.
- [How to Set Up a Firebase Account for FCM Notifications](https://www.logiclooptech.dev/setup-firebase-fcm-account/): Set up a Firebase account for FCM push notifications step by step: project creation, credentials, and the settings you need before sending messages.

## Pages

- [About](https://www.logiclooptech.dev/about/): who Ayush Kaushik is and what he works on
- [Hire](https://www.logiclooptech.dev/hire/): freelance backend and AI engineering services