Free Developer Tools APIs

Open-source SEO, GEO (Generative Engine Optimization) and SERP intelligence platform powered by Umay AI with keyword research, backlink audits, and AI visibility tracking.

Fake online REST API for testing and prototyping client applications

Modern SMS gateway REST API allowing developers to send programmatic SMS via connected Android devices and SIM cards.

Remote HTTP MCP server for Menlo Insurance Services. Discover insurance products, policy quotes, and application forms with AI assistants.

Hosted REST API simulating user CRUD operations for frontend prototyping

HTTP request and response inspection service for testing HTTP clients

Concise, consistent, and legible SVG badges for GitHub READMEs

Robust online code execution engine supporting 60+ programming languages

High-performance multi-language code execution engine and sandbox

Simple public IP address lookup API with universal CORS support

Online JSON storage, schema validation, and RESTful document API

Generate and export beautiful source code screenshots and syntax images

Generate strong types and converters from JSON in multiple languages

Programmatic control over Vercel deployments, domains, edge middleware, and DNS

Continuous deployment orchestration, serverless functions, and form handling

Search public container images, tags, user repositories, and builds

GitHub repositories, pull requests, issues, commits, and user profiles

GitLab DevOps platform, CI/CD pipelines, merge requests, and projects

Node package metadata, version dependencies, and download telemetry

Stack Overflow questions, answers, comments, and user badges

Automated metrics, insights, and time tracking for software developers

Competitive programming contests, user rankings, and problem archive

Coding kata challenges, user katas, and programming ranking stats

All-in-one developer API providing web scraping, full-page screenshots, Google SERP data, and DNS/SSL diagnostics

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.

Programmatic website screenshot API with built-in ad blocking, cookie banner hiding, and HTML/PDF rendering

Web scraping API that manages proxies, browsers, and CAPTCHAs with a single REST API call and 5,000 free API credits

World's #1 web data platform with 72M+ residential IPs, Web Unlocker, Scraping Browser, and ready-to-use dataset APIs

Zero-dependency mathematical 1D barcode generator producing vector SVG barcodes from text.

Student and academic email verification service validating 10,000+ world universities instantly.

Deterministic User-Agent parser extracting browser, OS, hardware device, and AI crawler/bot signatures in <0.01ms.

Mathematical content analyzer computing Flesch Reading Ease, Grade Level, Gunning Fog, and reading durations.

Designed to manage and provide standardized responses for different error scenarios encountered during API calls. It ensures that error messages are consistent and useful for end-users and developers alike.

Free REST API to detect browser, OS, device from user agent string. Provides easy-to-use API to avoid user-agent parsing libraries.

Estimate age from names. Integrate age inference directly into workflows and perform efficient inference on big datasets with simple APIs.

Public, machine-readable dataset that compiles published fees, sources and notes for ancestral record requests across jurisdictions. The page offers JSON, CSV and Markdown exports and includes source URLs and retrieval timestamps.

OpenAPI Documentation for Autobahn GmbH's Autobahn API.

API zur Exportierung von Daten zu Lehrverträgen und Abschlüssen der Berufsbildung seit 2017, einschließlich Anzahl der Lehrverträge, neu registrierten Lehrverträgen und Abschlüssen der Qualifikationsverfahren nach Ausbildungsfeldern.

Acesso programático de informações relacionadas a CEPs, bancos, CNPJ, IBGE, feriados nacionais, tabela FIPE e muito mais, fornecendo endpoints modernos com baixa latência. Este projeto busca centralizar dados públicos para uma fácil e rápida consulta em aplicações.

The Bucketlist Inspiration API provides users with daily dream prompts and destination ideas to help them create and manage personal bucket lists. It offers a cookie-free, CORS-enabled JSON endpoint that can be embedded in websites and applications.

The CTP API provides integration methods for connecting the functionality and content of the Chinese Text Project with external web applications. It consists of a Plugin API for adding external tools and a JSON API for leveraging CTP features externally.

This API provides a comprehensive listing of public holidays in China for the year 2024. It includes the date, name of the holiday, and whether it is an off day or not.

Public dataset exposing published private-provider prices for cholecystectomy (gallbladder removal) in the UK. Data is available as machine-readable JSON and CSV and includes per-provider figures plus summary statistics.

Provides access to calendar data for any day, allowing users to retrieve various liturgical celebrations and details. It supports multiple languages and enables specific queries for feast names and calendar descriptions based on the selected calendar system.

A public dataset API that publishes the Colorado Roof Replacement Cost Index. It returns the computed median, per‑metro breakdown and the sourced figures as machine‑readable JSON, CSV and Markdown.

Public dataset of USDT P2P price and premium history available as downloadable CSV and JSON files. Files cover many fiat markets with 30-minute samples and are refreshed every 30 minutes.

The Crossref REST API allows users to search and retrieve metadata for scholarly works, including DOIs, ISSNs, and funder identifiers. It provides access to various endpoints that expose data on works, journals, funders, and more, facilitating sophisticated searches and integrations for research purposes.

Provides access to a dataset of detection runs performed by AntiBrow against public fingerprinting and anti-bot detectors. Users can retrieve results in JSON and CSV formats, which include detailed information about each run, checks, and their results without the need for an API key.

Free Digimon API using data from official and fan-based sources like Wikimon.net. Not affiliated with Bandai.

Machine-readable dataset of dilapidations survey cost figures (GBP) collected from provider pages, showing medians, ranges and source citations. Data is available as JSON, CSV and Markdown and includes retrieval dates.

REST + GraphQL API for the 5e SRD database

Este API proporciona información sobre el precio del Dólar Oficial, Dólar Blue, Dólar Bolsa, Dólar CCL, Dólar Mayorista y otras monedas en países de América del Sur como Argentina, Chile, Venezuela y Uruguay. Permite obtener cotizaciones actuales y datos históricos sobre estas divisas importantes.

Provides access to various data sets related to the Elering power and gas systems, including balancing data and capacity information. It offers endpoints for retrieving real-time data, historical records, and CSV file downloads for easy data handling.

Provides access to energy data. Allows users to retrieve and analyze energy consumption information.

Public dataset (machine-readable JSON/CSV) that reports an index of HVAC replacement prices for Florida. It provides a statewide median, per-source price entries, and retrieval dates.

The FUSSY API allows users to access and manipulate data related to hobbies through a structured database. This API supports posting and retrieving data, enabling integration with external applications and services.

Provides the Factoring Price Index for UK invoice finance, with median rates, source rows and breakdowns. Data is available as machine-readable JSON and CSV and includes source citations and retrieval dates.

Set API allows users to query and generate entities within a fantasy role-playing world. It supports various actions such as rolling items and characters via HTTP GET requests, making it easily accessible and compatible with JSON, CURL, and CORS.

Public dataset API exposing the Florida Roof Replacement Cost Index, including the median and per-source roof replacement figures. Machine-readable JSON, CSV and Markdown exports are provided for easy programmatic access.

This API automatically retrieves the current year for website footers, eliminating the need for manual updates each January. Designed for developers, it ensures that the displayed year is accurate and up to date, improving user experience while saving time and resources.

Provides access to dictionary data sourced from Wiktionary. It allows users to retrieve definitions, pronunciations, synonyms, antonyms, and translations for words in various languages without requiring an API key.

Provides information about fuel prices at gas stations in Spain.

The GBIF API provides a programmatic interface to query and publish biodiversity data on GBIF.org, enabling advanced queries not supported by the website. Users can integrate GBIF data into scripts, workflows, or analyses, ensuring reliable and automated results.

A simple API that predicts the gender of a person based on a first name

Allows users to search for locations, layers, or features using either text search or bounding box parameters. It supports three types of searches: location search, layer search, and feature search, enabling comprehensive data retrieval from the Swiss national geographic database.

This API allows you to retrieve issues associated with a specific GitHub repository using the owner's username and the repository name. It supports queries to get detailed information about different issues for improved project management.

This API provides up-to-date information about closures and diversions of hiking trails as well as cycle and mountain bike routes in Switzerland. Data is updated daily and presented in a standardized format for developers to integrate into their applications.

This API provides fast and efficient screenshots of specified web pages. Users can request screenshots for various dates, sizes, and formats, making it ideal for web monitoring and analysis.

The Insult API generates humorous and creative insults in various formats, allowing users to specify language and templates. It supports multiple languages, including English and corporate jargon, catering to different contexts and preferences.

The Invoice Extraction API is designed to process and extract data from invoices submitted in various formats. It parses key information such as vendor details, amounts, items, and dates, enabling integration with accounting and ERP systems.

The Is Even API checks whether a given integer is even or odd. It provides a simple endpoint where you can submit a number and receive a response indicating its parity.

The JMESPath free API provides a serverless endpoint for running JSON transformations using the JMESPath query language. It enables users to quickly filter, reshape, and extract data from JSON without the need for deploying any infrastructure.

Provides Japan public holiday data (English and Japanese names) as downloadable JSON, CSV, or iCalendar files. Data is free to use with no sign-up and is served with CORS for direct browser fetches.

A super simple key value database with APIs for setting and getting key/value pairs.

Super simple JSON API in Korean for GET, POST, PUT, DELETE actions providing JSON data in Korean for prototyping projects.

Provides access to a dataset containing addresses within the city of Cologne. It includes geospatial information and various formats for data retrieval, enabling navigation and analysis of geographic data related to buildings and urban structures.

Machine-readable Laundry Service Price Index for the UK, giving median per-kg prices and source-level figures. JSON and CSV downloads are provided and the dataset is re-read monthly.

Provides access to real-time information about participants, rankings, events, and historical data related to the Longevity World Cup. It enables users to retrieve public rankings, athlete profiles, and detailed competition rules, facilitating engagement with the longevity-focused sporting community.

Access Magic: The Gathering card and set information through HTTPS endpoints. SDKs available for easier consumption.

Search makeup products by brand, price, product category, tags, and more. Provides visual representation of JSON data.

Provides access to various resources related to MapleStory, a popular MMORPG. It includes functionalities for character data, items, mobs, quests, and more, catering to developers creating tools and applications for the MapleStory community.

This API provides a visualization tool that helps users understand and optimize their MySQL queries through easy-to-read graphical outputs. It transforms the cryptic output of MySQL's EXPLAIN command into interactive graphics, assisting users in identifying performance issues and understanding complex query plans.

The Mydentify Public API allows users to access product directories and weekly leaderboard data. It enables the creation of product listings and supports requests without an API key, making it user-friendly for developers.

A simple API that estimates the nationality of a person based on a last name.

Nextbike Bikesharing API

Provides information about Nobel Prizes and Laureates. Offers endpoints to list and search data, returning results in JSON or CSV format.

Open Topo Data is a REST API server that provides access to elevation data. Users can utilize the free public API or host their own server with customizable datasets.

Open-Elevation is a free and open-source elevation API that provides elevation data for geographical points. Users can easily access elevation information over a broad dataset, offering a reliable alternative to commercial elevation services.

Allows searching and downloading parking records in Stadt St.Gallen with various parameters. Data includes parking locations, availability, occupancy, and more.

Dieses API ermöglicht den Zugriff auf Daten zu Passantenfrequenzen an verschiedenen Standorten in Zürich. Die Messungen werden stündlich aktualisiert und umfassen Informationen über die Anzahl der Passanten, unterteilt nach Zonen, Geschlecht und Laufrichtung sowie Wetterdaten.

PhantomJsCloud API offers a REST-like, JSON-based interface for web page rendering and automation. It allows you to submit page requests and receive various output formats like JPEG, PNG, and PDF while handling page interactions via an automation API.

Free UK postcode lookup API and datasets. Search, validate and reverse geocode postcodes.

Machine-readable dataset of published mortgage figures for pubs and licensed-trade lending. Returns JSON, CSV and Markdown exports with lender-level figures, source links and retrieval dates.

This API provides the current timestamp in various formats, including text, JSON, and CSS custom properties. It supports different endpoints for specific use cases, such as returning UNIX timestamps or sending periodic updates via Server-Sent Events and WebSockets.

Dieses API bietet Beispiele für REST API Aufrufe, insbesondere für die HTTP Methoden POST, PUT und PATCH. Es dient als Anleitung, um Ressourcen zu erstellen, zu aktualisieren oder zu löschen, wobei ein Beispielservice verwendet wird.

Get requested color, complementary color, grayscale, and corresponding text color in different formats.

Provides access to a comprehensive collection of data related to the Star Wars universe including characters, droids, creatures, locations, organizations, species, and vehicles. It is a RESTful API that presents official information derived directly from the Star Wars Databank, allowing users to explore and interact with the vast lore of the saga.

A free, CORS-enabled REST API serving over 220,000 sourced industry statistics from many primary publishers. Every datapoint includes full provenance and a ready-made citation, and data is published under CC BY 4.0.

Allows users to retrieve and search for obsolete cards in JSON format. Users can also find functional reprints and access various endpoints with a limit on the number of results per request.

Free API for accessing sumo database including rikishi, basho, banzuke, torikumi, hoshitori, matches, and more. Explore sumo data, learn about sumo history, and check match results.

Card names, descriptions, and divinatory meanings based on AE Waite's Pictorial Key to the Tarot (1910) for the Rider-Waite-Smith deck. Access via REST API with endpoints for getting cards and documentation.

Public JSON API that returns EDF Tempo tariff colors (BLEU/BLANC/ROUGE) for today and tomorrow, plus remaining days, predictions and history. No signup or API key required.

Provides access to detailed information regarding the popular television show 'The Office.' Users can retrieve data about seasons, characters, and episodes, including air dates and descriptions. The API is currently in early development, indicating that features may evolve over time.

API for truth, dare, would you rather, never have I ever, and paranoia questions with different ratings available.

Public dataset reporting median published UK basement construction prices (GBP per m²) with source sentences and read dates. Data is available as machine-readable JSON, CSV and Markdown on the site.

Machine-readable dataset publishing the UK Commercial Mortgage Rate Index (median, min/max, quartiles) and the underlying per-source rates, with dates and source links. Data is available as JSON, CSV and Markdown for programmatic access or embedding.

Public dataset with machine-readable exports for a UK washroom service price index. Provides per-source price figures plus computed median, min/max and retrieval dates in JSON and CSV.

Allows users to parse and retrieve information about user agents for free. It has no limitations or rate limiting, enabling unlimited requests by simply calling the appropriate endpoint with the user agent string.

This API parses user agent strings, providing structured information about the client's browser, operating system, and device type. Users can retrieve detailed data by submitting their user agent string along with an API key.

Veabird Beach API provides free JSON feeds with live beach conditions and sargassum forecasts for resort locations. It returns beach-day grades, sargassum levels, water and air conditions, and a 16-day outlook per resort.

Public dataset endpoint that publishes a Vet SEO Provider Index with median published monthly fees and source rows. The page provides machine-readable JSON and CSV exports of the dataset for easy consumption.

Reverse-Engineered Vogel-Datenbank der Schweiz mit verschiedenen Endpoints

This API provides a comprehensive dataset of historical Wordle answers along with their difficulty ratings and progressive hints. It allows users to query daily answers, filter results by various criteria, and retrieve data in JSON format for easy integration into applications.

This API provides detailed information about the qualification process for the FIFA World Cup for different confederations around the world. It includes tournament structures, match schedules, and results for qualifying matches.

Free and open source API providing information about world wonders

Version 2 API for /post that returns responses in json only. Provides additional information over the standard API with features like tag searches, limiting responses, including tag types, votes, and pool membership.

Ziptastic API allows users to retrieve location information based on the zip code provided. It returns details such as the country, state, and city associated with each zip code, making it easy to integrate location lookup into applications.

The openSenseMap API allows for managing users, senseBoxes (stations), and measurements, providing functionalities such as posting new data, retrieving sensor information, and managing senseBoxes. It also supports various operations with parameters for filtering and formatting responses, including JSON and CSV formats.

Search, discover, and download osu! beatmaps effortlessly.

国会会議録検索システムに登録されているデータを検索するためのAPIです。HTTPのGETメソッドを使用して、指定された条件で会議録や発言情報をXMLまたはJSON形式で取得できます。検索結果は、会議開催日の新しい順にソートされます。

IUCN Red List of Threatened Species

Adoption

Simple REST API that can scan submitted documents/files for the presence of threats

Read-only lookup for published face-shape guide records

Convert colors, check WCAG and APCA contrast, build palettes, gradients and tokens

RijksMuseum Data

Easily create word clouds

Onchain GraphQL APIs & DEX APIs

Multichain block explorer REST API (with Etherscan-compatible JSON-RPC)

Build hybrid smart contracts with Chainlink

To retrieve Walltime's market info

Bhagavad Gita API in telugu and odia languages

KDP niche demand scores, competition analysis and revenue estimates

1330 Thirukkural poems and explanation in Tamil and English

Get information from the Harry Potter universe

API to manage your BI dashboards and data sources on Superset

Non-profit charity data

Search for company logos and embed them in your projects

People and company data covering profiles, headcount, funding and contacts

Hire freelancers to get work done

Companies that just raised funding, scored as sales leads, from public SEC filings

Official company data from 56 European business registers as normalized JSON

Post to and update maintenance and incidents on your status page through an HTTP REST API

Automated code review platform auditing AI-generated code with test-driven validation, security scanning, edge-case testing, and performance optimization.

Dynamic Open Graph (OG) social card image generation API creating customized branded share banners for blogs and developer docs.

Free developer utility platform for international mobile phone carrier verification, IP geolocation, proxy diagnostics, and WHOIS domain lookups.

Model Context Protocol (MCP) server enabling AI coding assistants (Cursor, Claude) to query live NuGet packages, versions, and dependencies via NuGet v3 API.

Local-first, private file utility app featuring in-document search, PDF conversion, editing, redaction, and offline tooling running directly in the browser.

Lightweight CLI tool resolving website domains to IP addresses with geolocation coordinates, region telemetry, and interactive map links.

Agent-first search API delivering live Google autocomplete suggestions and search results. Features instant anonymous key minting with zero signup required for fast programmatic queries.

Open and keyless REST API listing independent benchmarks, score rankings, providers, and pricing plans across modern B2B and GTM data enrichment APIs.

Domain intelligence and SEO analysis API evaluating expired domains, backlink profiles, spam signals, WHOIS records, and domain authority with an integrated 32-tool MCP server.

Screenshot API converting URL, HTML, or Markdown into PNG, JPEG, WebP, PDF, or scrolling videos with full page and dark mode support.

Web data API for AI builders: scrape, crawl, map domains, and extract clean JSON or Markdown with proxy and headless rendering.