KeepRule Investment Principles API

Free, open-source API serving curated investment wisdom from the world's greatest investors — Warren Buffett, Charlie Munger, Benjamin Graham, Peter Lynch, Howard Marks, Ray Dalio, and more.

Powered by KeepRule — Your guide to timeless investment principles.

API Endpoints

All endpoints are static JSON files hosted on GitHub Pages. No authentication required.

Endpoint	Description
/api/principles.json	100 investment principles with author, category & source
/api/authors.json	List of all investment masters
/api/categories.json	Investment principle categories

Base URL: https://henu-wang.github.io/keeprule-api

Data Format

Principles

{
  "total": 100,
  "source": "https://keeprule.com",
  "principles": [
    {
      "id": 1,
      "text": "Rule No. 1: Never lose money. Rule No. 2: Never forget Rule No. 1.",
      "author": "Warren Buffett",
      "category": "Risk Management",
      "source": "Berkshire Hathaway Annual Meeting"
    }
  ]
}

Authors

{
  "total": 18,
  "authors": [
    {
      "id": 1,
      "name": "Warren Buffett",
      "title": "Chairman & CEO, Berkshire Hathaway",
      "known_for": "Value Investing, Long-term Holding",
      "principles_count": 20
    }
  ]
}

Categories

{
  "total": 13,
  "categories": [
    {
      "id": 1,
      "name": "Risk Management",
      "description": "Principles about identifying, assessing, and mitigating investment risks",
      "principles_count": 14
    }
  ]
}

Usage Examples

cURL

# Get all principles
curl https://henu-wang.github.io/keeprule-api/api/principles.json

# Get authors
curl https://henu-wang.github.io/keeprule-api/api/authors.json

# Get categories
curl https://henu-wang.github.io/keeprule-api/api/categories.json

JavaScript

// Fetch all investment principles
const response = await fetch('https://henu-wang.github.io/keeprule-api/api/principles.json');
const data = await response.json();

// Get a random principle
const random = data.principles[Math.floor(Math.random() * data.total)];
console.log(`"${random.text}" — ${random.author}`);

// Filter by author
const buffett = data.principles.filter(p => p.author === 'Warren Buffett');
console.log(`Found ${buffett.length} Buffett principles`);

// Filter by category
const risk = data.principles.filter(p => p.category === 'Risk Management');
console.log(`Found ${risk.length} risk management principles`);

Python

import requests
import random

# Fetch all principles
response = requests.get('https://henu-wang.github.io/keeprule-api/api/principles.json')
data = response.json()

# Random principle
principle = random.choice(data['principles'])
print(f'"{principle["text"]}" — {principle["author"]}')

# Filter by author
munger = [p for p in data['principles'] if p['author'] == 'Charlie Munger']
print(f'Found {len(munger)} Munger principles')

Featured Investors

Investor	Principles	Known For
Warren Buffett	20	Value Investing, Long-term Holding
Charlie Munger	13	Mental Models, Multidisciplinary Thinking
Benjamin Graham	10	Margin of Safety, Security Analysis
Peter Lynch	10	Invest in What You Know
Howard Marks	10	Second-Level Thinking
Ray Dalio	10	Principles-Based Investing
Philip Fisher	7	Growth Investing, Scuttlebutt Method
John Templeton	4	Global Contrarian Investing
+ 10 more	...	...

Categories

Risk Management, Value Investing, Market Psychology, Long-term Thinking, Mental Models, Decision Making, Circle of Competence, Portfolio Management, Business Quality, Self-improvement, Contrarian Thinking, Research, Compounding

About KeepRule

KeepRule is an interactive platform for exploring investment principles from the world's greatest investors. Features include:

• Scenario-based learning with real-world investment situations
• Principles organized by master investor and category
• AI-powered investment wisdom chat

License

This API is free to use for personal and commercial projects. Attribution to KeepRule is appreciated but not required.

Data is provided for educational purposes only and does not constitute financial advice.

🔗 More KeepRule Resources

Free Tools

• Investor Personality Quiz - Which legendary investor are you?
• Investment Scorecard - Rate any stock like Buffett
• Portfolio Health Check - Grade your portfolio
• Fear & Greed Calculator - Market sentiment tool
• Decision Tree - Buy/Hold/Sell guidance
• Investment Calculators - Compound interest, retirement, DCA & more
• 30-Day Challenge - Transform your investing

For Developers

• Free API - 100 principles, 20 authors
• NPM Package - npm install keeprule
• PyPI Package - pip install keeprule
• Chrome Extension
• Discord Bot
• Embeddable Widget

Learning

• Master Guides - Buffett, Munger, Graham & more
• Free Ebook - 100 Investment Principles
• Email Course - 7-day Buffett course
• Infographics - Visual investing guides
• Investment Glossary - 100 terms every investor should know
• Annual Report - State of Investment Principles 2026
• SEO Blog - Deep-dive investing articles
• Platform Comparisons - KeepRule vs alternatives

---

Built by William Wang | All Tools