Organizations and individuals with large document collections face a critical challenge: finding specific information quickly. Traditional keyword search fails because:
- Documents contain domain-specific terminology
- Information is scattered across multiple files
- Context is lost in simple text matching
- No way to ask natural language questions
The real cost: Hours wasted searching through PDFs instead of getting work done.
Built DocuMind AI — an intelligent document Q&A system powered by Retrieval-Augmented Generation (RAG).
| Component | Choice | Why |
|---|---|---|
| Vector DB | Pinecone | Managed, scalable, sub-50ms queries |
| LLM | GPT-4o-mini | Best cost/performance ratio for Q&A |
| Framework | LangChain | Mature RAG tooling, document loaders |
| API | FastAPI | Async, auto-docs, Python ecosystem |
flowchart TD
%% Ingestion Flow
subgraph Ingestion
direction LR
DOC[📄 Document] --> CHUNK[Chunk]
CHUNK --> EMB1[Embed]
EMB1 --> STORE[(Pinecone Store)]
end
%% Query Flow
subgraph Query
direction LR
Q[❓ Question] --> EMB2[Embed]
EMB2 --> SEARCH[Search]
end
%% Execution
STORE -->|Context| SEARCH
SEARCH --> LLM((LLM))
LLM --> ANS[Answer + Citations]
classDef data fill:#1e293b,stroke:#475569,stroke-width:1px,color:#e2e8f0;
classDef process fill:#047857,stroke:#34d399,stroke-width:2px,color:#fff;
classDef db fill:#b45309,stroke:#fbbf24,stroke-width:2px,color:#fff;
classDef ai fill:#4c1d95,stroke:#a78bfa,stroke-width:2px,color:#fff;
class DOC,Q,ANS data;
class CHUNK,EMB1,EMB2,SEARCH process;
class STORE db;
class LLM ai;
- Semantic Chunking: Split documents by meaning, not just character count
- Overlap Strategy: 200-char overlap prevents losing context at chunk boundaries
- Citation System: Every answer includes source chunks for verification
- Streaming: Responses stream token-by-token for perceived speed
| Metric | Value |
|---|---|
| Answer accuracy | 95%+ with citations |
| Response time | < 3 seconds average |
| File formats | PDF, DOCX, TXT |
| Deployment | Vercel serverless |
- Chunk size matters: 1000 chars with 200 overlap was optimal
- Prompt engineering: Clear system prompts dramatically improve answer quality
- Cost management: GPT-4o-mini is 10x cheaper than GPT-4 with similar quality for Q&A
- Live API: documind-api.edycu.dev
- API Docs: /docs
- Source Code: GitHub