Free Development APIs

24 Pull Requests is a community initiative that runs every December to encourage developers to contribute to open source projects.

Agify.io is a free API that predicts the likely age of a person based solely on their first name, using a database of over 350 million historical records.

API Grátis is a Brazilian API aggregator that bundles multiple free utility services including CEP (postal code) lookup, CNPJ (company registry) data, vehicle plate information, and more — all under a single authentication token.

ApicAgent parses User-Agent strings into structured device and browser information, returning details like browser name, version, OS, device type, and whether the client is a bot.

APIs.guru maintains a crowd-sourced directory of OpenAPI (Swagger) specification files for hundreds of public web APIs, all normalized to OpenAPI 3.0 format.

Beeceptor lets you create a mock REST API endpoint in seconds directly from your browser, without writing any server code.

Bored provides programmatic access to find random activities to fight boredom via REST API.

The CDNJS API provides metadata about JavaScript and CSS libraries hosted on cdnjs.com, one of the largest open source CDN networks.

Changelogs.md aggregates and structures changelog data from popular open source projects hosted on GitHub, making it easy to fetch and display version history programmatically.

Ciprand is a lightweight public API for generating cryptographically secure random strings, useful for creating tokens, nonces, salts, and test data without implementing your own randomness logic.

The Cloudflare Trace API exposes request metadata collected by Cloudflare's edge network, including your public IP address, country code, datacenter IATA code, HTTP version, TLS version, and user agent—all in a single request.

Codex provides programmatic access to online compiler for various languages via REST API.

CORS Proxy acts as a middle-man server that forwards your HTTP requests to external APIs, stripping restrictive CORS headers so browsers can access them without cross-origin errors.

CountAPI provides programmatic access to free and simple counting service.

The DigitalOcean Status API provides real-time and historical data on the operational status of all DigitalOcean services, including Droplets, Managed Databases, Kubernetes, Spaces, and more.

DomainsDB.info provides a searchable database of registered domain names, allowing you to find all domains containing specific keywords, phrases, or patterns across various TLDs.

ExtendsClass JSON Storage is a simple REST API that lets you create, read, update, and delete JSON objects online without any backend setup.

Genderize.io predicts the likely gender of a given first name using a statistical model trained on a database of over 100 million names from around the world.

host-t.com provides DNS lookups over plain HTTP GET requests, making it easy to query DNS records without specialized libraries.

HTTP2.Pro is a testing service that lets you verify whether a client or server supports the HTTP/2 protocol via a simple API call.

Httpbin is a classic developer tool that echoes back HTTP requests in structured JSON, making it invaluable for testing HTTP clients, inspecting headers, and debugging network code.

Httpbin Cloudflare provides programmatic access to a simple http request & response service with http/3 support by cloudflare via REST API.

Icanhazepoch is a minimalist API that returns the current Unix epoch timestamp as a plain integer, with no frills and no authentication required.

Icanhazip returns your public IP address as a plain text string with no authentication, parsing, or configuration needed.

The IFTTT Connect API allows developers to integrate their services with IFTTT automation platform, enabling users to create "if this, then that" automations that connect thousands of apps and IoT devices.

Image-Charts generates chart images and QR codes on-the-fly via a simple GET request URL, with chart parameters encoded directly into the query string.

ip-fast.com is a lightweight, no-auth API that returns the caller's IP address along with associated country and city information.

IPify is an extremely simple, free API with no authentication required that returns your current public IP address as plain text or JSON.

IPinfo is a free, no-auth-required IP geolocation and network intelligence API that returns rich data about any IP address including location, organization, ASN, and timezone.

jsDelivr's Data API provides programmatic access to package metadata and download statistics for npm, GitHub, and WordPress packages hosted on the jsDelivr CDN.

JSON 2 JSONP is a free, no-auth service that acts as a JSONP proxy, converting any JSON endpoint into a JSONP response on the fly to bypass browser cross-domain restrictions in legacy applications.

Kroki is a free, open-source API that converts plain-text diagram descriptions into images (SVG, PNG, PDF) supporting over 20 diagram types including Mermaid, PlantUML, Graphviz, and more.

License-API is an unofficial REST wrapper around choosealicense.com that lets you fetch structured data about open-source licenses by their SPDX identifier.

Lua Decompiler provides programmatic access to online lua 5.1 decompiler via REST API.

MicroENV is a hosted fake REST API that returns realistic-looking mock data for common entities such as users, posts, and todos, making it ideal for front-end prototyping without a real backend.

Mocky provides programmatic access to mock user defined test json for rest api endpoints via REST API.

MY IP is a straightforward API that returns the public IP address of the caller along with associated geolocation metadata such as country, city, ISP, and coordinates.

Nationalize.io predicts the likely nationality of a person based on their first name by analyzing a large database of name-to-country associations.

NetworkCalc provides programmatic access to network calculators, including subnets, dns, binary, and security tools via REST API.

The npm Registry API exposes package metadata for every module published to the npm ecosystem, including version history, author information, download counts, and README content.

oyyi is a versatile utility API that lets developers generate fake/test data, convert and optimize images and videos, compress PDFs, and create thumbnails — all without authentication.

The QRtag QR Code API generates clean, scan-ready QR code images from any URL or text with a single GET request — no authentication or signup required.

The goQR.me QR Code API is a straightforward REST service for generating and decoding QR codes — you can produce a QR image from any text or URL with a single GET request and receive a PNG back, or POST an image to decode its contents.

QRcode Monkey provides a free API to generate highly customizable QR codes with logos, custom colors, and various dot styles — far beyond the plain black-and-white output of simpler QR APIs.

QuickChart turns Chart.js configuration objects into chart images via a simple GET or POST request — no JavaScript runtime or canvas library required.

ReqRes is a free, hosted fake REST API designed for testing and prototyping front-end applications.

RSS feed to JSON is a free, no-auth API that converts any RSS feed URL into structured JSON data.

Serialif Color is a free, no-auth API that converts colors between formats like HEX, RGB, and HSL.

SHOUTCLOUD is a fun, no-auth API that converts any text string into ALL CAPS, delivered as a humorous "ALL-CAPS AS A SERVICE." It requires no authentication and responds instantly, making it a great first API for absolute beginners learning how HTTP POST requests work.

Sonar provides a fast DNS enumeration API built on Project Sonar's large passive DNS dataset, allowing you to look up subdomains associated with any domain.

Statically is a free CDN for developers that accelerates static assets from GitHub, GitLab, npm, and WordPress, with no account or API key required.

Wandbox provides programmatic access to code compiler supporting 35+ languages mentioned at wandbox.org via REST API.