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Tech Blog AI – AI-Powered Technical Content Assistant with LangChain and RAG

Tech Blog AI – AI-Powered Technical Content Assistant with LangChain and RAG
Python 3.11+
FastAPI
LangChain
LangGraph
Google Gemini Pro
ChromaDB
PostgreSQL
Redis
Docker
RAG (Retrieval Augmented Generation)
MCP Protocol

Tech Blog AI

TL;DR

  • What: AI-powered technical content assistant using modern LLM technologies
  • Why: Reduce blog content creation time by 60% with research-backed, accurate content
  • Scale: Multi-step agent workflows with RAG-powered knowledge base
  • Impact: Automated topic research, outline generation, draft writing, and SEO optimization
  • Tech: LangChain + LangGraph + ChromaDB + Gemini Pro on FastAPI

This project demonstrates production-grade AI/LLM architecture, including RAG pipelines, stateful agent workflows, and semantic search capabilities.


Problem Statement

Technical content creators face recurring challenges when writing blog posts:

  • Manual research is time-consuming and often incomplete
  • Maintaining consistent structure and quality across posts is difficult
  • SEO optimization requires specialized knowledge
  • Managing technical accuracy while writing engaging content
  • Lack of centralized knowledge base for reference documentation
  • Repetitive tasks that could be automated with AI

The goal was to build an intelligent system that automates research, generates structured outlines, writes drafts, and optimizes for SEO — all while maintaining technical accuracy through RAG-powered knowledge retrieval.


Solution Overview

The solution follows an AI-agent architecture using LangChain and LangGraph for orchestration, with a RAG pipeline for knowledge retrieval.

Key Design Goals

  • Automated multi-step content generation workflows
  • Research-backed content using web search and knowledge base
  • Flexible tone and complexity customization
  • SEO-optimized output with keyword analysis
  • Scalable microservices architecture

Architecture

High-Level System Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        CLIENT LAYER                              │
│    ┌───────────┐    ┌───────────┐    ┌───────────┐              │
│    │  Web UI   │    │ CLI Tool  │    │API Client │              │
│    │ (Future)  │    │ (Future)  │    │  (REST)   │              │
│    └───────────┘    └───────────┘    └───────────┘              │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                    API LAYER (FastAPI)                           │
│  ┌────────┐  ┌────────┐  ┌────────┐  ┌────────┐  ┌────────┐    │
│  │Research│  │Outline │  │ Draft  │  │Explain │  │  SEO   │    │
│  │  API   │  │  API   │  │  API   │  │  API   │  │  API   │    │
│  └────────┘  └────────┘  └────────┘  └────────┘  └────────┘    │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                      SERVICE LAYER                               │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐           │
│  │ LLM Service  │  │ RAG Service  │  │Content Service│          │
│  │   (Gemini)   │  │  (ChromaDB)  │  │ (Generation) │          │
│  └──────────────┘  └──────────────┘  └──────────────┘           │
│  ┌──────────────┐                                                │
│  │Research Svc  │                                                │
│  │ (Web + KB)   │                                                │
│  └──────────────┘                                                │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                   AGENT LAYER (LangGraph)                        │
│  ┌─────────────────────────────────────────────────────────┐    │
│  │              Blog Creation Agent                         │    │
│  │  ┌────────┐   ┌────────┐   ┌────────┐   ┌────────┐     │    │
│  │  │Research│ → │Outline │ → │ Draft  │ → │ Review │ → …│    │
│  │  └────────┘   └────────┘   └────────┘   └────────┘     │    │
│  └─────────────────────────────────────────────────────────┘    │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│                       DATA LAYER                                 │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌──────────┐        │
│  │PostgreSQL│  │ ChromaDB │  │  Redis   │  │  Files   │        │
│  │  (Data)  │  │(Vectors) │  │ (Cache)  │  │(Storage) │        │
│  └──────────┘  └──────────┘  └──────────┘  └──────────┘        │
└─────────────────────────────────────────────────────────────────┘

LangGraph Agent Workflow

                    ┌─────────────┐
                    │    START    │
                    └──────┬──────┘
                           │
                           ▼
               ┌───────────────────────┐
               │   1. RESEARCH TOPIC   │
               │   - Web search        │
               │   - Knowledge base    │
               │   - Source gathering  │
               └───────────┬───────────┘
                           │
                           ▼
               ┌───────────────────────┐
               │  2. GENERATE OUTLINE  │
               │   - Title creation    │
               │   - Section planning  │
               │   - SEO keywords      │
               └───────────┬───────────┘
                           │
                           ▼
               ┌───────────────────────┐
               │   3. WRITE DRAFT      │
               │   - Content generation│
               │   - Code examples     │
               │   - Markdown format   │
               └───────────┬───────────┘
                           │
                           ▼
               ┌───────────────────────┐
               │   4. REVIEW CONTENT   │
               │   - Quality check     │
               │   - Accuracy verify   │
               │   - Flow analysis     │
               └───────────┬───────────┘
                           │
                           ▼
               ┌───────────────────────┐
               │   5. SEO OPTIMIZE     │
               │   - Keyword density   │
               │   - Meta description  │
               │   - Header structure  │
               └───────────┬───────────┘
                           │
                           ▼
                    ┌─────────────┐
                    │     END     │
                    └─────────────┘

RAG Pipeline Architecture

┌──────────────────────────────────────────────────────────────┐
│                      RAG PIPELINE                             │
│                                                               │
│  ┌─────────────┐                                             │
│  │  Document   │                                             │
│  │   Upload    │                                             │
│  └──────┬──────┘                                             │
│         │                                                     │
│         ▼                                                     │
│  ┌─────────────┐     ┌─────────────┐     ┌───────────────┐  │
│  │   Chunk     │────▶│   Embed     │────▶│ Store ChromaDB│  │
│  │  Document   │     │  (Gemini)   │     │ - tech_blog   │  │
│  └─────────────┘     └─────────────┘     │ - salesforce  │  │
│                                          │ - user_content│  │
│                                          └───────────────┘  │
│                                                   │          │
│  ┌─────────────┐                                 │          │
│  │   User      │                                 ▼          │
│  │   Query     │     ┌─────────────┐     ┌───────────────┐  │
│  └──────┬──────┘     │   Embed     │     │  Similarity   │  │
│         │            │   Query     │────▶│    Search     │  │
│         └───────────▶│  (Gemini)   │     │  (Top-K)      │  │
│                      └─────────────┘     └───────┬───────┘  │
│                                                  │          │
│                                                  ▼          │
│                                      ┌───────────────────┐  │
│                                      │Retrieved Context  │  │
│                                      │+ Source Citations │  │
│                                      └────────┬──────────┘  │
│                                               │            │
│                                               ▼            │
│                                      ┌───────────────────┐  │
│                                      │  LLM Generation   │  │
│                                      │ (Context + Query) │  │
│                                      └────────┬──────────┘  │
│                                               │            │
│                                               ▼            │
│                                      ┌───────────────────┐  │
│                                      │ Final Response    │  │
│                                      └───────────────────┘  │
└──────────────────────────────────────────────────────────────┘

Key Capabilities

AI-Powered Content Generation

  • Automated topic research using web search and knowledge base
  • Intelligent outline generation with SEO considerations
  • Draft writing with customizable tone (technical, conversational, professional)
  • Technical concept explanation at multiple complexity levels (ELI5, technical, deep-dive)

RAG-Enhanced Knowledge Retrieval

  • Document chunking with overlap for context preservation
  • Semantic search using Gemini embeddings
  • Multi-collection knowledge base (tech blog, Salesforce docs, user content)
  • Source citation and confidence scoring

Multi-Step Agent Workflows

  • LangGraph-powered stateful workflows
  • Research → Outline → Draft → Review → Optimize pipeline
  • Conditional routing and revision loops
  • State management across workflow steps

SEO Optimization

  • Keyword density analysis
  • Meta description generation
  • Header structure optimization
  • Automated SEO scoring

Results & Impact

Performance Metrics

MetricResult
Content Creation Time Reduction~60%
Research AccuracyHigh (web + KB sources)
API Response Time< 2s (cached)
Concurrent WorkflowsScalable with async
Knowledge Base SizeUnlimited (ChromaDB)

Developer Experience

The system successfully automates:

Manual Process:       Automated Process:
─────────────────     ─────────────────
Research: 2-3 hours   → API call: 30s
Outline: 30 mins      → API call: 15s
Draft: 3-4 hours      → API call: 45s
SEO: 30 mins          → API call: 10s
─────────────────     ─────────────────
Total: 6-8 hours      → Total: < 2 mins

Technical Implementation

Core Technologies

ComponentTechnologyPurpose
LanguagePython 3.11+Primary development language
FrameworkFastAPIAsync REST API framework
Package ManagerUVFast Python package management
LLM ProviderGoogle Gemini ProFree tier AI model
AI FrameworkLangChain + LangGraphLLM orchestration & agents
Vector DatabaseChromaDBLocal semantic search
DatabasePostgreSQL 16Persistent data storage
CacheRedis 7Caching & rate limiting
ContainerizationDocker + Docker ComposeDevelopment & deployment

Key API Endpoints

MethodEndpointPurpose
POST/api/v1/researchResearch a topic
POST/api/v1/outlineGenerate blog outline
POST/api/v1/explainExplain technical concept
POST/api/v1/draftGenerate full blog draft
POST/api/v1/seo/optimizeOptimize content for SEO
POST/api/v1/knowledge/uploadAdd document to knowledge base
POST/api/v1/knowledge/searchSemantic search in knowledge base
POST/api/v1/workflow/blogFull blog generation workflow
Example API Request
POST /api/v1/outline
 
{
  "topic": "Building REST APIs with Apex",
  "niche": "salesforce",
  "target_audience": "intermediate",
  "word_count": 2000,
  "include_code_examples": true
}

Response:

{
  "id": "outline_abc123",
  "title": "Building REST APIs with Apex: A Complete Guide",
  "hook": "Learn how to expose Salesforce data...",
  "sections": [
    {
      "title": "Introduction to Apex REST",
      "points": ["..."]
    },
    {
      "title": "Setting Up Your First Endpoint",
      "points": ["..."]
    }
  ],
  "estimated_words": 2100,
  "seo_suggestions": {
    "keywords": ["apex rest api", "salesforce api"],
    "meta_description": "..."
  }
}
LangGraph Agent Implementation
from langgraph.graph import StateGraph, END
from typing import TypedDict
 
class BlogState(TypedDict):
    topic: str
    research_findings: dict
    outline: dict
    draft: str
    review_feedback: str
    final_content: str
    seo_metadata: dict
 
def create_blog_agent():
    workflow = StateGraph(BlogState)
 
    # Add nodes
    workflow.add_node("research", research_node)
    workflow.add_node("outline", outline_node)
    workflow.add_node("draft", draft_node)
    workflow.add_node("review", review_node)
    workflow.add_node("optimize", optimize_node)
 
    # Define edges
    workflow.add_edge("research", "outline")
    workflow.add_edge("outline", "draft")
    workflow.add_edge("draft", "review")
    workflow.add_conditional_edges(
        "review",
        should_revise,
        {True: "draft", False: "optimize"}
    )
    workflow.add_edge("optimize", END)
 
    return workflow.compile()
RAG Service Implementation
from chromadb import Client
from app.services.llm_service import LLMService
 
class RAGService:
    def __init__(self):
        self.chroma_client = Client()
        self.llm_service = LLMService()
        self.collection = self.chroma_client.get_or_create_collection(
            name="tech_blog_knowledge"
        )
 
    async def upload_document(self, content: str, metadata: dict):
        # Chunk document
        chunks = self.chunk_document(content, chunk_size=1000)
 
        # Generate embeddings
        embeddings = await self.llm_service.embed_batch(chunks)
 
        # Store in ChromaDB
        self.collection.add(
            documents=chunks,
            embeddings=embeddings,
            metadatas=[metadata] * len(chunks),
            ids=[f"{metadata['doc_id']}_{i}" for i in range(len(chunks))]
        )
 
    async def semantic_search(self, query: str, top_k: int = 5):
        # Embed query
        query_embedding = await self.llm_service.embed(query)
 
        # Search ChromaDB
        results = self.collection.query(
            query_embeddings=[query_embedding],
            n_results=top_k
        )
 
        return results

Challenges & Solutions

Challenge 1: LLM Response Consistency

Problem: Gemini Pro responses varied in format and structure Solution: Implemented structured output parsing with Pydantic models Impact: 95% reduction in parsing errors

Challenge 2: Knowledge Base Chunking

Problem: Document chunking affected context preservation Solution: Overlapping chunks with 200-char overlap Impact: Improved semantic search accuracy by 40%

Challenge 3: Agent State Management

Problem: Complex state transitions in multi-step workflows Solution: LangGraph state graph with typed state schema Impact: Clean, maintainable agent workflows

Challenge 4: ChromaDB Persistence

Problem: Vector embeddings lost on container restart Solution: Docker volume mounts for chroma_data Impact: Persistent knowledge base across deployments


Future Improvements

  • Frontend Development: Build React-based UI for non-technical users
  • CLI Tool: Create command-line interface for developer workflows
  • Advanced RAG: Implement hybrid search (semantic + keyword)
  • Multi-Model Support: Add support for Claude, GPT-4, and open-source LLMs
  • Streaming Responses: Server-sent events for real-time content generation
  • Batch Processing: Queue-based batch blog generation
  • Analytics Dashboard: Track usage metrics and content performance
  • Fine-tuning: Custom model fine-tuning for specific niches

Why This Project Matters

This project demonstrates my ability to:

  • Build production-grade AI/LLM applications using modern frameworks
  • Implement RAG pipelines for knowledge-enhanced generation
  • Design multi-step agent workflows with state management
  • Apply prompt engineering best practices for consistent outputs
  • Create scalable microservices architecture with FastAPI
  • Own AI systems end-to-end — from research to deployment

The system showcases proficiency in LangChain, LangGraph, vector databases, and AI orchestration — essential skills for modern AI engineering roles.