AI Engineering Guide: Build and Secure LLM Features
Calling a model is easy; making an LLM feature safe, measurable and affordable is the real work. This guide starts with how LLM apps are built, then follows the AI engineering series through security, evaluation, cost and production guardrails.
The demos use a fake model, so you can run everything without an API key.
Who it is for: Full-stack developers adding LLM features to products, and candidates for AI engineering roles.
8 lessons · Published by Jainik · Last updated
1. How LLM apps are built
- 1. Full-Stack Questions · 45 minLLMs, Agentic AI, RAG and Harnesses
Agent vs agentic AI, workflows vs agents, the harness, MCP, RAG end to end, evaluation and safety.
- 2. Full-Stack Questions · 40 minVercel AI SDK Interview Questions
streamText, tools, structured output, multi-step loops, useChat, testing and security.
- 3. Full-Stack Questions · 40 minVector Databases, pgvector, Retrieval Evals and LLM Cost
Distance measures, HNSW and IVFFlat, the filter trap, hybrid search, golden sets, judges, prompt caching and tracing.
2. Security
- 4. AI Engineering · 14 minSecuring LLM Applications: The OWASP Top 10 for LLM Apps in Code
The ten 2025 OWASP risks for LLM applications, each with a plain definition, a vulnerable sketch, a fix and a one-line interview answer.
- 5. AI Engineering · 13 minPrompt Injection and Safe Tool Use for Agents
Direct and indirect injection, a mock agent leaking private notes, and a policy layer that blocks the leak.
3. Quality, cost and production
- 6. AI Engineering · 14 minBuilding an Evaluation Harness for an LLM Feature
A golden set, code checks and a mock judge, confidence intervals, and a CI gate that catches a regression.
- 7. AI Engineering · 20 minCost, Latency and Caching for LLM Features
Token arithmetic, time to first token, prompt and response caching, model routing, batching, timeouts and budgets, with a simulation.
- 8. AI Engineering · 18 minObservability and Guardrails for LLM Features in Production
What to log and what never to log, spans, redaction, schema validation, a circuit breaker, a kill switch, prompt versions and an incident playbook.
More reading orders are on the guides page, and every series is listed on the home page.