5 Free APIs Every Developer Should Know About in 2026

#api #webdev #javascript #freecodecamp

Building side projects? You know the pain — most useful data APIs either cost $50+/month or have laughably small free tiers.

I built a suite of 5 free APIs for the data developers actually need. Each one has a free tier of 100 requests/day (enough for prototyping and small apps), and paid tiers starting at $9.99/month if you need more.

All are hosted on RapidAPI with full documentation and code examples.

1. Currency Exchange Rate API

What: Real-time and historical exchange rates for 31 currencies, sourced from the European Central Bank.

Endpoints: Latest rates, historical (back to 1999!), currency conversion, time series, supported currencies list.

Why it's different: Most currency APIs charge $15-50/month for basic access. This one is free for 100 req/day and $9.99/month for production use. Sub-50ms response times on Cloudflare's edge network.

Use it for: Currency converters, multi-currency e-commerce, finance dashboards, travel apps.

Try it: Currency Exchange Rate API on RapidAPI

const response = await fetch('https://currency-exchange-rates13.p.rapidapi.com/rates/latest', {
  headers: {
    'x-rapidapi-key': 'YOUR_KEY',
    'x-rapidapi-host': 'currency-exchange-rates13.p.rapidapi.com'
  }
});
const data = await response.json();
console.log(data.rates.USD); // 1.0842

2. Air Quality Index (AQI) API

What: Real-time air quality data for any city — AQI score, individual pollutant readings (PM2.5, PM10, O3, NO2, SO2, CO), and health recommendations.

Endpoints: Current AQI by city, city pollution rankings, historical data, health advice.

Why it's different: Most AQI APIs just give you a number. This one includes health recommendations in every response (e.g., "Sensitive groups should limit outdoor exertion") and lets you rank cities by pollution levels.

Use it for: Weather apps, health trackers, smart home dashboards, data visualization projects.

Try it: Air Quality Index API on RapidAPI

import requests

url = "https://air-quality-index2.p.rapidapi.com/current"
querystring = {"city": "London"}
headers = {
    "x-rapidapi-key": "YOUR_KEY",
    "x-rapidapi-host": "air-quality-index2.p.rapidapi.com"
}
response = requests.get(url, headers=headers, params=querystring)
print(response.json())

3. UV Index & Sun Exposure API

What: Current UV index, 7-day hourly forecast, and — the unique part — safe sun exposure times calculated by Fitzpatrick skin type with vitamin D synthesis estimates.

Endpoints: Current UV, forecast, safe exposure calculator, vitamin D estimates, historical UV data.

Why it's different: No other UV API calculates personalized safe exposure times for all 6 Fitzpatrick skin types or estimates vitamin D production. It's health data, not just weather data.

Use it for: Health/fitness apps, travel planners, dermatology tools, outdoor sports platforms.

Try it: UV Index & Sun Exposure API on RapidAPI

curl -X GET "https://uv-index-sun-exposure.p.rapidapi.com/uv/current?lat=40.7128&lng=-74.006" \
  -H "x-rapidapi-key: YOUR_KEY" \
  -H "x-rapidapi-host: uv-index-sun-exposure.p.rapidapi.com"

4. US Fuel & Energy Price API

What: Gas prices (regular, midgrade, premium, diesel) and electricity rates (residential, commercial, industrial) for all 50 US states. Historical data back to 1990.

Endpoints: Current gas prices by state, national averages, electricity rates by sector, historical trends.

Why it's different: 35+ years of government-sourced data (EIA) in one API. No other free-tier API combines gas and electricity data. Great for data-heavy projects.

Use it for: Fleet management, travel apps, real estate (utility cost comparisons), EV cost calculators, data journalism.

Try it: US Fuel & Energy Price API on RapidAPI

const response = await fetch('https://us-fuel-energy-prices.p.rapidapi.com/gas/prices/state/CA', {
  headers: {
    'x-rapidapi-key': 'YOUR_KEY',
    'x-rapidapi-host': 'us-fuel-energy-prices.p.rapidapi.com'
  }
});
const data = await response.json();
console.log(`California regular gas: $${data.regular}/gallon`);

5. Sales Tax & VAT Validation API (Coming Soon)

What: US state/local sales tax rates, EU VAT rates, and Canadian GST/HST/PST — plus EU VAT number validation.

Use it for: E-commerce checkout, invoicing, tax compliance, SaaS billing with regional tax handling.

Listing going live soon — follow Two Hundred OK on RapidAPI to get notified.

Why I Built These

I kept running into the same problem: I needed simple data for a side project and every API was either expensive, unreliable, or had a 10-request/day free tier. So I built a suite of APIs on Cloudflare Workers (global edge, fast responses) with genuinely useful free tiers.

All 5 APIs share the same design philosophy: