WorldPop — Free Global Population Data API (No Key)

TL;DR

WorldPop provides high-resolution (approximately 100m) population distribution data for the entire planet, developed by the University of Southampton. The API allows you to query estimated population counts for specific coordinates, download raster tiles, and access demographic data for research, urban planning, and humanitarian applications. It is one of the most authoritative free sources of gridded population data, used by the UN and World Bank.

Quick start: https://www.worldpop.org/api/population

No API key needed — just make a request!

How to Use This API

1. Get Population Data by Coordinates

Query population estimates for specific latitude/longitude points:

https://www.worldpop.org/api/population

2. JavaScript — Population at Location

// WorldPop API typically requires POST with lat/lon
const body = { lat: 40.7128, lon: -74.0060 };
fetch('https://www.worldpop.org/api/population', {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify(body)
})
  .then(r => r.json())
  .then(d => console.log('Population density:', d));

3. Python — Query Multiple Points

import requests, json

# WorldPop provides data downloads and tile services
# For programmatic access, their WMS/TMS tile services work well
url = 'https://www.worldpop.org/api/population'
points = [
    {'lat': 40.7128, 'lon': -74.0060},  # NYC
    {'lat': 51.5074, 'lon': -0.1278},    # London
    {'lat': 35.6762, 'lon': 139.6503},   # Tokyo
]
resp = requests.post(url, json={'points': points})
print(resp.json())

API Details

API URL: https://www.worldpop.org/api
Documentation: www.worldpop.org/apis
Category: Data
Authentication: Not Required
Geographic Coverage: Global

Frequently Asked Questions

What is the spatial resolution of WorldPop data?: The standard resolution is approximately 100 meters (3 arc-seconds) at the equator. This means population is estimated for roughly 100m x 100m grid cells.
What years are covered?: WorldPop provides estimates for multiple years including 2000, 2005, 2010, 2015, 2020, and future projections. Data for different years may have different methodologies.
Can I download raster files?: Yes, WorldPop offers GeoTIFF downloads for offline analysis. The API is primarily for point queries and small-area extractions at this time.
What is the difference between population count and density?: Count is the estimated number of people in each grid cell. Density is people per square kilometer. Both are available from WorldPop datasets.
Is this data suitable for academic research?: Yes, WorldPop is widely cited in academic literature. They request that you cite their papers and data sources in any publications using the data.

What You Can Build

Population density heatmap for any region in the world
Urban planning tool with demographic estimates
Emergency response resource allocation calculator
Market analysis tool for retail location planning
Environmental impact studies with population exposure data