Finnhub API Integration Services for Fintech Apps | FintegrationFS

Finnhub API — Real-Time Stock Market Data for US Fintech Developers

What is Finnhub API?

The Finnhub API is an institutional-grade financial data platform designed for developers, fintech startups, investment firms, and individual traders across the United States. Built by ex-engineers from Google, Bloomberg, and Tradeweb, Finnhub provides real-time stock prices, global fundamentals, alternative financial data, and economic indicators — all through a single, developer-friendly REST API and WebSocket feed.

Whether you are building a trading platform, a personal finance app, an investment research tool, or a robo-advisor, the Finnhub API delivers the financial data infrastructure you need to compete in the US market.

Official Website: https://finnhub.io API Documentation: https://finnhub.io/docs/api

Who Uses Finnhub API?

The Finnhub API is used by a wide range of professionals and organizations in the US financial ecosystem, including:

• Individual investors and retail traders

• Fintech startups building investment apps

• Financial analysts and quantitative researchers

• Hedge funds and asset management firms

• Academic institutions studying capital markets

• Software developers building financial dashboards

Finnhub API Key Features

Finnhub API Pricing Plans (USA)

Getting Started with Finnhub API in Python

Below is a complete example to get you started with the Finnhub API using Python. Install the library first:

pip install finnhub-python

Fetch Real-Time Stock Quote & Company Profile

import finnhub
import os

# Initialize the Finnhub client
finnhub_client = finnhub.Client(api_key="YOUR_FINNHUB_API_KEY")

# --- Real-Time Stock Quote ---
quote = finnhub_client.quote('AAPL')
print("Current Price:", quote['c'])
print("Day High:", quote['h'])
print("Day Low:", quote['l'])
print("Previous Close:", quote['pc'])
print("Change %:", quote['dp'])

# --- Company Profile ---
profile = finnhub_client.company_profile2(symbol='AAPL')
print("\nCompany Name:", profile['name'])
print("Industry:", profile['finnhubIndustry'])
print("Market Cap ($B):", round(profile['marketCapitalization'] / 1000, 2))

# --- Earnings Surprises ---
earnings = finnhub_client.company_earnings('TSLA', limit=5)
print("\nRecent Tesla Earnings:", earnings)

# --- Recent Company News ---
news = finnhub_client.company_news('AAPL', _from="2024-01-01", to="2024-01-15")
for article in news[:3]:
    print(article['headline'])

Fetch Historical OHLCV Candlestick Data

import finnhub
import pandas as pd
import datetime

finnhub_client = finnhub.Client(api_key="YOUR_FINNHUB_API_KEY")

# Convert dates to UNIX timestamps
from_ts = int(datetime.datetime(2024, 1, 1).timestamp())
to_ts   = int(datetime.datetime(2024, 6, 30).timestamp())

# Daily candles for MSFT
res = finnhub_client.stock_candles('MSFT', 'D', from_ts, to_ts)

# Convert to Pandas DataFrame
df = pd.DataFrame(res)
df['date'] = pd.to_datetime(df['t'], unit='s')
df = df.rename(columns={'o': 'Open', 'h': 'High', 'l': 'Low', 'c': 'Close', 'v': 'Volume'})
print(df[['date', 'Open', 'High', 'Low', 'Close', 'Volume']].head())

Real-Time WebSocket Stream (Live Trades)

// Node.js WebSocket example
const WebSocket = require('ws');

const ws = new WebSocket('wss://ws.finnhub.io?token=YOUR_FINNHUB_API_KEY');

ws.on('open', function open() {
  // Subscribe to real-time trades for AAPL and AMZN
  ws.send(JSON.stringify({ type: 'subscribe', symbol: 'AAPL' }));
  ws.send(JSON.stringify({ type: 'subscribe', symbol: 'AMZN' }));
});

ws.on('message', function incoming(data) {
  const msg = JSON.parse(data);
  if (msg.type === 'trade') {
    msg.data.forEach(trade => {
      console.log(`Symbol: ${trade.s} | Price: ${trade.p} | Volume: ${trade.v}`);
    });
  }
});

Finnhub API Endpoints Reference

Finnhub API vs Competitors: US Market Comparison

Top Use Cases for Finnhub API in the USA

1. Stock Screener & Portfolio Tracker Build a custom dashboard that pulls real-time quotes, fundamentals, and earnings data to help US investors screen and track their portfolios.

2. Algorithmic Trading Systems Use Finnhub's WebSocket feed for low-latency tick data to power US-based algorithmic and high-frequency trading strategies.

3. Robo-Advisor Applications Combine fundamental data, ETF holdings, and earnings calendar endpoints to automate investment recommendations for retail clients.

4. SEC Filing Analysis Leverage Finnhub's NLP-powered sentiment analysis on 10-K and 10-Q filings to identify early signals of financial health changes among US-listed companies.

5. Financial News Aggregation Use the news and social sentiment endpoints to build a real-time financial news feed with sentiment scoring for trading signals.

6. ESG & Responsible Investing Tools Access ESG risk scores and congressional trading data to power ethical investment screening applications for US investors.

7. Market Research & Academic Studies The generous free tier and historical data access make Finnhub ideal for quantitative researchers and universities studying US capital markets.

Advantages of Integrating Finnhub API

• Institutional-grade data accessible to startups and individual developers at a fraction of traditional vendor costs

• One of the most generous free tiers in financial APIs — 60 calls/minute with no credit card required

• Unique alternative datasets such as insider sentiment (MSPR), senate lobbying, government contracts, and social media sentiment that are not available on competing APIs

• WebSocket streaming available on the free plan — rare among financial data providers

• Global coverage spanning 60+ exchanges, with especially deep coverage for US equities, ETFs, and SEC filings

• Multi-language SDK support including Python, JavaScript/Node.js, Go, R, and more

• Featured by Columbia University and ranked #1 on Towards Data Science stock API

Finnhub API Integration Support at FintegrationFS

At FintegrationFS, our US-based fintech development team specializes in integrating the Finnhub API into production-grade financial applications. We help you with:

• End-to-end Finnhub API integration into web and mobile apps

• WebSocket implementation for real-time trading dashboards

• Data pipeline design for historical and alternative financial data

• Compliance and security review for fintech products targeting US users

• Choosing the right Finnhub plan and data endpoints for your specific use case

FAQ

Q1. What is the Finnhub API used for? 

The Finnhub API is used to access real-time stock prices, historical market data, company fundamentals, SEC filings, earnings calendars, insider transactions, alternative financial data, and financial news. It is widely used by US developers building trading platforms, investment apps, and financial research tools.

Q2. Is Finnhub API free to use? 

Yes. Finnhub offers a free tier with 60 API calls per minute, real-time US stock quotes, company news, basic fundamentals, SEC filings access, and WebSocket streaming for up to 50 symbols — all at no cost. No credit card is required to get started.

Q3. How do I get a Finnhub API key? 

Visit https://finnhub.io, create a free account, and your API key will be available immediately in your dashboard. You can start making API calls within minutes.

Q4. Does Finnhub API provide real-time data for US stocks? 

Yes. Finnhub provides real-time trade and quote data for US stocks listed on major exchanges including NYSE and NASDAQ via both REST endpoints and WebSocket streaming.

Q5. What programming languages does Finnhub API support? 

Finnhub provides official client libraries for Python, JavaScript/Node.js, Go, R, Ruby, and Kotlin. You can also call the REST API from any language that supports HTTP requests (Java, C#, PHP, etc.).

Q6. Can I access SEC filings through Finnhub API? 

Yes. Finnhub's /stock/filings endpoint provides access to 10-K, 10-Q, and 8-K SEC filings. Additionally, the /financials/sentiment endpoint offers NLP-powered sentiment analysis on filings to detect unusual language shifts that may signal stock price movements.

Q7. What alternative data does Finnhub API offer? 

Finnhub offers a range of alternative data rarely found in competing APIs, including social media sentiment (Reddit/Twitter), insider transactions and MSPR sentiment scoring, senate/congressional trading data, government contracts, lobbying records, FDA approval calendars, earnings call transcripts, and ESG scores.

Q8. How does Finnhub API compare to Alpha Vantage or Polygon.io? 

Finnhub stands out for its free WebSocket streaming, alternative data sets (lobbying, insider sentiment, ESG), and SEC filing access — features not typically available on Alpha Vantage's free tier. Compared to Polygon.io, Finnhub's free tier is more comprehensive for fundamental data, though Polygon.io excels for institutional-grade tick data on paid plans.

Q9. What is the rate limit for Finnhub API free plan? 

The free plan supports up to 60 API calls per minute and WebSocket connections for up to 50 symbols simultaneously.

Q10. Can FintegrationFS help integrate Finnhub API into my US fintech product? 

Absolutely. FintegrationFS specializes in fintech API integrations for US-based products. Our team can help you integrate the Finnhub API into your application, design efficient data pipelines, implement real-time WebSocket dashboards, and ensure your integration is production-ready and compliant.