Ranjan Kumar
AI & ML Engineer · Author · Educator
I help AI builders design, build, and ship production-grade AI systems that actually work, cost-effectively, through hands-on writing, books, and practical engineering guidance.
Latest Posts
View all →Why Your RAG Knowledge Base Is Lying About What It Knows
The vector index is a snapshot of your documents at ingestion time. Semantic similarity has no relationship to temporal validity. A document from 18 months ago can score 0.94 cosine similarity and still be completely wrong today - and nothing in the standard RAG pipeline raises a flag.
ai-engineeringWhy Your Reranker Is the Last Line You Forgot to Build
Retrieval gets you recall. Reranking gets you precision. Skipping it means your LLM reads the wrong documents with complete confidence - and you will not know until production.
ai-engineeringWhy Your RAG System Cannot Tell When It Is Wrong
Most RAG pipelines measure answer quality and ignore retrieval quality - which means the Retrieval Tax, Chunking Debt, and Precision Gap from Parts 1 through 4 are accumulating invisibly, query by query, until a production incident forces the question.
ai-engineeringWhy Your Agentic RAG System Costs 10x More Than It Should
Wrapping a well-built RAG pipeline in an agent loop multiplies every cost in the stack by the number of retrieval iterations - and most teams have no budget ceiling, no per-session spend tracking, and no circuit breaker.
My Books
The ChatML Handbook
Structured Prompting & LLM Conversations
Learn how to structure prompts using ChatML for predictable, production-ready LLM behavior.
Building Real-World Agentic AI Systems
From Prototypes to Production
A practitioner's guide to designing, deploying, and operating reliable agentic AI systems in the real world.
My Toolkit
A collection of tools I've built to boost productivity and simplify workflows.
Developer & AI Tools
Test Your Knowledge
Quiz yourself on AI engineering, observability, and production LLM systems
MedhaV - मेधावी
Start every day with clarity
Imagelly
AI-Based SaaS Image Edit/Enhancement Tool
Mermaid Diagram Generator
Create flowcharts, sequence diagrams, and more
MermAniSt — Mermaid Animation Studio
Turn Mermaid diagrams into animated presentations
LinkedIn Text Formatter
Format your LinkedIn posts with bold, italic, and more
MarkMelon: Markdown Editor
Edit, generate docs from Markdown and more
Slides Creator from Markdown
Generate beautiful presentations from Markdown
What I Write About
AI & ML Engineering
Production-ready AI systems, LLMs, and machine learning deployment strategies.
System Design
Scalable architectures, distributed systems, and infrastructure for AI applications.
Real-World Projects
Case studies, lessons learned, and practical insights from production deployments.