development APIs

Userstack is a User-Agent string parsing API that detects browser type, version, operating system, and device category from a raw UA string in real time.

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.

ApiFlash provides a REST API that captures full-page or viewport screenshots of any public URL using a headless Chrome browser, returning the image as a PNG, JPEG, or WebP file.

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.

Azure DevOps REST API provides programmatic access to all Azure DevOps services including work items, repositories, pipelines, test plans, and artifact feeds.

Base provides programmatic access to building quick backends via REST API.

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

The Bitbucket REST API (v2) provides programmatic access to Bitbucket Cloud repositories, pull requests, pipelines, and user accounts, enabling you to automate code review workflows and integrate Bitbucket into your CI/CD toolchain.

Blitapp is a screenshot-as-a-service API that lets you capture full-page or viewport screenshots of any web page on a schedule, then automatically sync them to cloud storage like Dropbox or Google Drive.

Blynk Cloud is an IoT platform API that allows you to read and write values to virtual pins on hardware devices (such as Arduino or Raspberry Pi) connected to the Blynk server.

Browshot is a screenshot API that captures web pages rendered in real browsers (Chrome, Firefox) at any screen resolution or as any device type, including mobile and tablet.

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.

The Contentful Images API lets you retrieve, resize, crop, convert format, and apply other transformations to images stored in your Contentful media library by simply appending query parameters to the image URL.

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.

The Databricks REST API lets you programmatically manage clusters, notebooks, jobs, and workspaces on the Databricks platform — a cloud-based analytics and machine learning environment built on Apache Spark.

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.

The Docker Hub API lets you programmatically interact with Docker Hub registries — searching repositories, pulling image metadata, managing tags, and automating image builds.

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.

GeekFlare provides programmatic access to provide numerous capabilities for important testing and monitoring methods for websites via REST API.

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.

The Ghost Content API provides read-only access to posts, pages, tags, authors, and settings published on a Ghost CMS instance — letting you pull your blog content into any frontend, app, or static site generator.

The GitHub REST API gives you programmatic access to nearly everything on GitHub — repositories, issues, pull requests, commits, users, organizations, GitHub Actions, and more.

The GitLab REST API provides comprehensive programmatic control over GitLab projects, including repositories, merge requests, pipelines, issues, CI/CD variables, and user management.

Glitterly is an image generation API that lets you create customized graphics, banners, and visual assets programmatically.

The Google Docs API provides full programmatic control over Google Docs documents, including reading content, inserting text, applying styles, and managing document structure.

Google Firebase provides a suite of backend services for mobile and web applications, including a real-time database, authentication, cloud storage, and cloud messaging, all accessible via REST APIs.

The Google Fonts API provides metadata about all font families hosted on Google Fonts, including available variants, subsets, and file download URLs.

The Google Keep API allows applications to read and create notes in Google Keep, including text notes, lists, and notes with attachments.

The Google Sheets API enables full programmatic control of spreadsheets — reading cell data, writing values, applying formatting, managing sheets, and creating charts.

The Google Slides API allows you to create, read, and modify Google Slides presentations programmatically, including managing slides, text boxes, images, shapes, and speaker notes.

Gorest is a free online REST API service designed for testing, prototyping, and development — it provides fake but realistic user, post, comment, and todo data via standard CRUD endpoints.

Hasura is a GraphQL and REST API engine that auto-generates a powerful API layer on top of your PostgreSQL, MySQL, or other supported databases with built-in authorization, subscriptions, and remote joins.

The Heroku Platform API provides full programmatic control over your Heroku apps, dynos, add-ons, pipelines, and configuration variables.

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

Host.io aggregates domain data including DNS records, web technology fingerprints, backlinks, and related domains into a single REST API.

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.

Hunter (hunter.io) provides APIs to find and verify professional email addresses associated with any domain, making it a go-to tool for sales prospecting and lead enrichment.

IBM Text to Speech converts written text into natural-sounding audio using deep neural network models that support multiple languages and voices.

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.

import.io is a web scraping and data extraction API that lets you retrieve structured data from any website or RSS feed programmatically.

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

IP2WHOIS provides a simple REST API to look up WHOIS registration data for any domain name, including registrar info, creation date, expiry date, and registrant details.

ipfind.io is a geolocation API that returns detailed location data for any IP address or domain name, including country, region, city, timezone, and ASN 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.

JSONbin.io is a free cloud-based JSON storage and hosting service that lets you create, read, update, and delete JSON data bins via a simple REST API.

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.

Logs.to provides programmatic access to generate logs via REST API.

macaddress.io resolves any MAC address or OUI (Organizationally Unique Identifier) prefix to the hardware vendor that manufactured the network interface.

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.

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.

The Netlify API provides full programmatic control over your Netlify account, including deploying sites, managing custom domains, retrieving build logs, and configuring environment variables.

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.

Open PageRank provides a free alternative to Google's original PageRank score for any domain, calculated from the Common Crawl dataset of billions of web pages.

OpenAPIHub is an all-in-one API management platform that hosts, documents, and discovers APIs using the OpenAPI specification.

OpenGraphr is a lightweight API that extracts Open Graph metadata from any publicly accessible URL, returning properties such as title, description, image, and site name in a clean JSON format.

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.

PageCDN exposes a public API to query its CDN library catalog — including JavaScript packages, CSS frameworks, and web fonts — so developers can look up available versions and generate optimized CDN URLs programmatically.

The Postman API provides programmatic access to your Postman workspace — letting you manage collections, environments, mocks, monitors, and API schemas without opening the Postman desktop or web app.

ProxyCrawl (now Crawlbase) is an anti-bot scraping and crawling API that routes requests through rotating residential and datacenter proxies, handles CAPTCHAs automatically, and returns the rendered HTML of JavaScript-heavy pages.

Pusher Beams is a managed push notification API that enables developers to send reliable push notifications to Android and iOS devices without managing their own FCM/APNs infrastructure.

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.

Rejax provides a reverse AJAX (server-sent events / long-polling) infrastructure as a service, allowing server-side applications to push real-time updates to connected web clients without those clients needing to constantly poll your backend.

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.

SavePage.io provides a RESTful API for capturing full-page screenshots of any desktop or mobile website.

ScrapeNinja is a web scraping API that uses real Chrome browser fingerprints and residential proxies to bypass anti-bot protections.

ScraperApi is a web scraping infrastructure service that handles proxy rotation, browser rendering, and CAPTCHA solving so developers can extract data from websites with a simple GET request.

Scrapestack is a real-time web scraping and proxy REST API that routes requests through a global pool of residential and datacenter proxies.

ScrapingAnt is a headless Chrome-based web scraping API that renders JavaScript-heavy pages and rotates proxies automatically.

ScrapingDog is a proxy-based web scraping API that handles IP rotation, CAPTCHAs, and JavaScript rendering to help developers reliably extract data from websites.

AbstractAPI's Website Screenshot API lets developers programmatically capture full-page or viewport screenshots of any website URL and receive the image directly in the response.

ScreenshotAPI.net is a developer-friendly API for generating pixel-perfect screenshots of any website, supporting custom viewport sizes, full-page capture, and mobile device emulation.

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

serpstack delivers real-time Google Search results through a simple REST API, returning organic results, ads, featured snippets, and more.

Sheetsu (now SheetDB) lets you turn any Google Spreadsheet into a REST API with full CRUD support.

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.

SonarQube provides a REST API for its code quality and security analysis platform, letting you programmatically retrieve metrics, issues, and quality gate statuses for your projects.

The StackExchange API gives you programmatic access to all Stack Overflow and Stack Exchange network sites, including questions, answers, users, tags, and comments.

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

Supportivekoala is an API that auto-generates custom images by filling in templates with dynamic text or data, returning a ready-to-use image URL.

WebScraping.AI is a web scraping API that handles JavaScript rendering, proxy rotation, and CAPTCHA bypassing automatically, so you get clean HTML or text from any webpage with a single request.

ZenRows is a web scraping API that automatically bypasses anti-bot protections, CAPTCHAs, and IP bans so you can extract data from any website.