Free APIs Without API Key

Query-aware context and token compression engine for LLMs. Fits long documents into prompt token budgets by extracting relevant excerpts

Developer platform offering PDF merge, split, compress, and image conversion/resizing tools through a single versioned REST API (v1). Includes free guest and registered member tiers.

Converts public WeChat articles into clean Markdown for AI assistants, LLM pipelines, and research workflows. Features anonymous zero-card access, daily free credits, and a hosted MCP server.

Public REST JSON and MCP service for 5,400+ perfumes, notes, fragrance pyramids, accords, and seasonal profiles. Zero auth, open CORS, and no signup required.

High-speed free IP lookup API returning geolocation, ASN/ISP, and VPN/Proxy/Tor detection signals. HTTPS, zero-auth, and open CORS.

Open index of industry statistics from primary publishers across 32 industries, linking figures directly to source reports.

Zero registration required, 16-day forecasts, free for non-commercial applications

Official US National Weather Service open API, requires User-Agent header

Norwegian Meteorological Institute open public weather feeds with User-Agent policy

Public API for Aare river data including temperature, flow rate, weather forecasts, and more. Non-commercial use allowed with customizable app and version parameters.

Provides access to data from around 160 automatic measurement stations within the SwissMetNet network. It delivers vital meteorological data including temperature, precipitation, wind speed, and humidity every 10 minutes to support weather forecasting and environmental monitoring.

This API provides machine-to-machine access to aviation weather data, including METARs, TAFs, AIRMETs, and SIGMETs. It enables users to fetch up-to-date weather information for flight planning and operations.

This API provides current weather data for a specified location, presenting information visually through Glax. Users can retrieve data in JSON or PNG formats and customize their queries with parameters like location, units, and forecast options.

The Meteoprog Weather API provides comprehensive weather data, allowing integration of fast and accurate weather forecasts into various applications and websites. It offers endpoints for current weather, forecasts, historical data, and more, ensuring easy access to vital meteorological information.

This API provides real-time readings of temperature, humidity, precipitation, and wind conditions across various weather stations in Singapore at intervals of up to one minute. Managed by the National Environment Agency (NEA), it allows users to access detailed weather data for public use.

The UV Index API provides real-time and 5-day forecast data for UV index levels based on geographic coordinates. It's free to use with no API key required, making it accessible for developers to integrate into their applications.

This API provides weather data, including current conditions, forecasts, and historical weather information. It allows users to access weather information for various locations worldwide.

The WeatherTotals JSON API provides real-time weather data including precipitation and snow information across various US states. The API does not require a key or signup, making it accessible for quick integration into applications.

Real-time weather radar without the clutter, providing live precipitation vectors, lightning activity telemetry, storm warnings, and historical meteorological data.

Open-source meteorological tool calculating FAO-style soil water balance and precipitation forecasts from Open-Meteo to optimize watering schedules.

Zero-auth public REST API providing 2023 USDA plant hardiness zones, 2012 historical climate comparison, and NOAA frost dates across 40,502 US ZIP codes.

Zero authentication required, comprehensive crypto market datasets

Real-time crypto market cap, exchange volume, and live pricing feeds

100% free crypto price ticker and decentralized token analytics