DocTalk

AI-powered document analysis and chat system using Google Vertex AI Search and Gemini.

Tech Stack

Backend: Spring Boot 3.4 (Java 21), Google Cloud Platform Frontend: Next.js 16, React, TypeScript, Tailwind CSS Infrastructure: Vertex AI Search, Firestore, Cloud Storage, Gemini 2.5 Pro

Features

• Project Management - Organize documents into isolated projects
• Document Storage - Upload PDFs, DOCX, TXT via signed URLs to GCS
• Flexible Storage - Use managed storage or Bring Your Own Bucket (BYOB) from GCS
• RAG Chat - Context-aware chat with document grounding and citations
• Search Infrastructure - Auto-provision Vertex AI Search datastores per project
• System Instructions - Customizable AI personas/prompts
• Real-time Streaming - Server-sent events for live chat responses
• Dark Mode - Responsive UI with theme support

Setup

Prerequisites

• Java 21+
• Node.js 18+
• Google Cloud Project with billing enabled
• gcloud CLI authenticated

GCP Permissions

Your service account needs:

roles/firestore.user
roles/storage.admin
roles/discoveryengine.admin
roles/aiplatform.user

Enable APIs:

gcloud services enable \
  firestore.googleapis.com \
  storage.googleapis.com \
  discoveryengine.googleapis.com \
  aiplatform.googleapis.com

Environment Variables

Create .env in project root:

GOOGLE_CLOUD_PROJECT=your-project-id
GCS_BUCKET_NAME=your-bucket-name
GEMINI_API_KEY=your-api-key  # Optional if using Vertex AI
GEMINI_MODEL=gemini-2.5-pro
GCP_LOCATION=us-central1

GCS CORS Configuration

Apply CORS to your bucket:

gsutil cors set gcs_cors.json gs://your-bucket-name

Run Backend

cd api
mvn spring-boot:run

Backend runs on http://localhost:8080

Run Frontend

cd web
npm install
npm run dev

Frontend runs on http://localhost:3000

Usage

1. Create Project - Set up a new document project (Managed or BYOB)
2. Upload Documents - Add files directly or use your external bucket
3. Provision Search - Automatically creates Vertex AI datastore
4. Sync Index - Import documents into the search index
5. Create Chat - Select a system instruction and start chatting
6. Query Documents - Ask questions and get cited answers

Storage Configuration

Managed Mode:

• We host your files in our central GCS bucket.
• You upload files directly via the UI.

BYOB Mode (Bring Your Own Bucket):

• You provide your own GCS bucket name and optional prefix.
• You manage file uploads using gsutil or the GCS Console.
• Requirement: Our service account needs Storage Object Viewer permission on your bucket.

Architecture

┌─────────────┐     ┌──────────────┐     ┌─────────────────┐
│   Next.js   │────▶│  Spring Boot │────▶│  Google Cloud   │
│   Frontend  │     │   REST API   │     │  - Firestore    │
└─────────────┘     └──────────────┘     │  - GCS          │
                                          │  - Vertex AI    │
                                          └─────────────────┘

Project Structure

doctalk/
├── api/                    # Spring Boot backend
│   └── src/main/java/     # Controllers, Services, Models
├── web/                    # Next.js frontend
│   ├── src/app/           # App routes
│   └── src/components/    # React components
└── docs/                   # Documentation