local-deep-research/docs/search-engines.md

Search Engines Guide

Local Deep Research integrates with multiple search engines to provide comprehensive research capabilities. This guide covers all available search engines, their specializations, and configuration details.

Note

: This documentation is maintained by the community and may contain inaccuracies. While we strive to keep it up-to-date, please verify critical information and report any errors via GitHub Issues.

Overview

LDR supports three categories of search engines:

• Free Search Engines - No API key required
• Premium Search Engines - Require API keys but offer enhanced features
• Custom Sources - Your own documents and databases

Search Engine Selection

Auto Engine (Recommended)

The auto search engine intelligently selects the most appropriate engines based on your query:

result = quick_summary(
    query="What are the latest advances in quantum computing?",
    search_tool="auto"  # Automatically selects best engines
)

Free Search Engines

Academic Search Engines

arXiv

• Specialization: Scientific papers and preprints
• Best for: Physics, mathematics, computer science, biology
• Results: Direct access to research papers
• Rate Limit: Moderate - automatic retry on limits

PubMed

• Specialization: Biomedical and life science literature
• Best for: Medical research, clinical studies, biology
• Results: Abstracts and links to full papers
• Rate Limit: Generous - rarely hits limits

Semantic Scholar

• Specialization: Academic literature across all fields
• Best for: Cross-disciplinary research, citation networks
• Results: Paper summaries with citation context
• Rate Limit: Moderate - adaptive rate limiting handles this

General Purpose

Wikipedia

• Specialization: General knowledge and encyclopedic information
• Best for: Background information, concepts, facts
• Results: Well-structured article content
• Rate Limit: Very generous

SearXNG (Highly Recommended)

• Specialization: Meta-search engine aggregating multiple sources
• Best for: Comprehensive web search with privacy
• Results: Aggregated results from Google, Bing, DuckDuckGo, etc.
• Setup:

  docker pull searxng/searxng
  docker run -d -p 8080:8080 --name searxng searxng/searxng
  

• Configuration: Set URL to http://localhost:8080 in settings

DuckDuckGo

• Specialization: Privacy-focused web search
• Best for: General web queries without tracking
• Results: Web pages, instant answers
• Rate Limit: Strict - use SearXNG for better reliability

Technical Search

GitHub

• Specialization: Code repositories and documentation
• Best for: Finding code examples, libraries, technical solutions
• Results: Repository information, code snippets, issues
• Rate Limit: Moderate when unauthenticated

Elasticsearch

• Specialization: Custom search within your Elasticsearch cluster
• Best for: Searching your own indexed data
• Configuration: See Elasticsearch Setup Guide

Historical Search

Wayback Machine

• Specialization: Historical web content
• Best for: Finding deleted content, tracking changes over time
• Results: Archived web pages with timestamps
• Rate Limit: Moderate

News Search

The Guardian

• Specialization: News articles and journalism
• Best for: Current events, news analysis
• Results: Recent news articles
• Note: Requires API key (free tier available at https://open-platform.theguardian.com/)

Wikinews

• Specialization: Open and collaboratively-written news articles on a wide range of topics
• Best for: Historical and recent news, general news coverage, quick overviews
• Results: News articles written by volunteers with verified sources

Premium Search Engines

Tavily

• Specialization: AI-optimized search for LLM applications
• Best for: High-quality, relevant results for AI research
• Pricing: Free tier available, paid plans for higher volume
• Configuration:

  # In .env file or web interface
  LDR_SEARCH_ENGINE_TAVILY_API_KEY=your-key-here
  

Google (via SerpAPI)

• Specialization: Comprehensive web search
• Best for: Most current and comprehensive results
• Pricing: Paid service with free trial
• Configuration:

  LDR_SEARCH_ENGINE_WEB_SERPAPI_API_KEY=your-key-here
  

Google Programmable Search Engine

• Specialization: Customizable Google search
• Best for: Searching specific sites or topics
• Pricing: Free tier with limits
• Configuration:

  LDR_SEARCH_ENGINE_WEB_GOOGLE_PSE_API_KEY=your-key-here
  LDR_SEARCH_ENGINE_WEB_GOOGLE_PSE_ENGINE_ID=your-engine-id
  

Brave Search

• Specialization: Independent search index with privacy focus
• Best for: Web search without big tech tracking
• Pricing: Free tier available
• Configuration:

  LDR_SEARCH_ENGINE_WEB_BRAVE_API_KEY=your-key-here
  

Custom Sources

Local Documents

• Specialization: Search your private documents
• Supported formats: PDF, TXT, MD, DOCX, CSV, and more
• Configuration: See Configuring Local Search
• Setup:
  1. Go to Settings → Search for "local"
  2. Add document collection paths
  3. Choose embedding model (CPU or Ollama)
  4. First search will index documents

LangChain Retrievers

• Specialization: Any vector store or database
• Supported: FAISS, Chroma, Pinecone, Weaviate, Elasticsearch
• Configuration: See LangChain Integration Guide

Search Performance Comparison

Engine	Speed	Quality	Privacy	Rate Limits
SearXNG	★★★★★	★★★★☆	★★★★★	★★★★★
Wikipedia	★★★★☆	★★★★☆	★★★★★	★★★★★
arXiv	★★★★☆	★★★★★	★★★★★	★★★☆☆
PubMed	★★★★☆	★★★★★	★★★★★	★★★★☆
Tavily	★★★★☆	★★★★★	★★★☆☆	★★★★☆
Google (SerpAPI)	★★★★☆	★★★★★	★★☆☆☆	★★★★★
Local Documents	★★★☆☆	★★★★★	★★★★★	★★★★★

Rate Limiting and Reliability

LDR includes intelligent adaptive rate limiting that:

• Learns optimal wait times for each engine
• Automatically retries failed requests
• Prevents your IP from being blocked
• Maintains high reliability

Managing Rate Limits

# Check rate limit status
python -m local_deep_research.web_search_engines.rate_limiting status

# Reset rate limits if needed
python -m local_deep_research.web_search_engines.rate_limiting reset

Search Strategies

LDR supports multiple search strategies that determine how queries are processed:

• source-based: Single query, fast results
• focused_iteration: Iterative refinement for accuracy (recommended)

Best Practices

1. For General Research: Use auto or searxng
2. For Academic Research: Combine arxiv, pubmed, and semantic_scholar
3. For Technical Questions: Use github with searxng
4. For Maximum Privacy: Use searxng with local Ollama models
5. For Best Quality: Use tavily or Google with focused_iteration strategy

Troubleshooting

SearXNG Not Working

• Verify container is running: docker ps | grep searxng
• Check URL in settings: http://localhost:8080
• Test directly: curl http://localhost:8080
• Check the logs: docker logs searxng or view them in the LDR web UI

Rate Limit Errors

• Wait a few minutes and retry
• Use auto engine for automatic fallbacks
• Consider adding premium engines for higher limits

No Results Found

• Try different search engines
• Broaden your query
• Check internet connectivity
• Verify API keys for premium engines

Advanced Configuration

Configuring Search Engines

You can enable/disable specific search engines and adjust their reliability parameters in the settings. This affects which engines are used in 'auto' mode and how the system handles rate limiting.

Parallel Search Configuration

Adjust parallel search settings:

result = quick_summary(
    query="your query",
    max_parallel_searches=5,  # Number of engines to query simultaneously
    timeout_per_engine=30     # Seconds per engine
)

Related Documentation

• API Quickstart
• Configuration Guide
• Full Configuration Reference
• LangChain Integration
• Elasticsearch Setup