Guides, Software, Technology

40 Free Testing APIs to Supercharge Your Projects (With Auth Examples & Google Sheets Integration)

August 10, 2025 No comments yet

Looking for free testing APIs to power your prototypes, learning projects, or data workflows? Whether you want to experiment with real-world data, automate business processes, or bring live feeds into Google Sheets, this curated list delivers. Every API is free to use for testing (some with generous free tiers), and we’ll spotlight those supporting Basic Auth or OAuth for more realistic authentication scenarios. Crypto, news, weather, and more included!

Pro tip:
Using API Parser, you can import any of these APIs into Google Sheets in minutes—no code required. With the built-in scheduler, you can even automate updates and keep your data fresh.

Table of Contents

Why Use Free Testing APIs?

  • Safe to experiment: No payment or credit card needed
  • Realistic workflows: Practice with real authentication (Basic, OAuth)
  • Diverse data: From crypto prices to movie info, public records, and more
  • Perfect for Google Sheets: Build dashboards, alerts, and automations

How to Import Any API to Google Sheets (API Parser)

With API Parser, you can:

  • Connect any REST API—even if it requires authentication.
  • Import JSON, CSV, or XML data into Sheets, mapped to columns automatically.
  • Schedule updates (hourly, daily, weekly).
  • Build live dashboards or automate reporting.

Quick Steps:

  1. Install API Parser from Google Workspace Marketplace.
  2. Paste your API endpoint and (if needed) set up auth.
  3. Map the response fields to your Sheet.
  4. (Optional) Schedule recurring imports with the built-in scheduler.

The 40 Free APIs You Can Connect

Below, you’ll find 40 free testing APIs. Each includes a sample endpoint, documentation link, and authentication method if required.

Public APIs (No Auth)

  1. CoinGecko Crypto Prices
    • Crypto Data
    • Endpoint: https://api.coingecko.com/api/v3/simple/price?ids=bitcoin,ethereum&vs_currencies=usd
    • Docs: CoinGecko API Docs
  2. Open-Meteo Weather
    • Endpoint: https://api.open-meteo.com/v1/forecast?latitude=40.71&longitude=-74.01&hourly=temperature_2m
    • Docs: Open-Meteo Docs
  3. ExchangeRate Host
    • Currency rates
    • Endpoint: https://api.exchangerate.host/latest
    • Docs: Docs
  4. REST Countries
    • Country data
    • Endpoint: https://restcountries.com/v3.1/all
    • Docs: Docs
  5. NASA Astronomy Picture of the Day
    • Requires free API key, no auth
    • Endpoint: https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY
    • Docs: NASA APOD
  6. TheCatAPI
    • Random cat images
    • Endpoint: https://api.thecatapi.com/v1/images/search
    • Docs: TheCatAPI
  7. JokeAPI
    • Programming jokes
    • Endpoint: https://v2.jokeapi.dev/joke/Programming
    • Docs: JokeAPI
  8. Open Trivia Database
    • Quiz questions
    • Endpoint: https://opentdb.com/api.php?amount=5
    • Docs: OpenTDB
  9. IPify
    • Get your public IP
    • Endpoint: https://api.ipify.org?format=json
    • Docs: IPify
  10. Dog CEO
    • Dog images
    • Endpoint: https://dog.ceo/api/breeds/image/random
    • Docs: Dog CEO
  11. BoredAPI
    • Activity ideas
    • Endpoint: https://www.boredapi.com/api/activity/
    • Docs: BoredAPI
  12. Numbers API
    • Random trivia about numbers
    • Endpoint: http://numbersapi.com/42/trivia
    • Docs: NumbersAPI
  13. SpaceX Launch Data
    • Endpoint: https://api.spacexdata.com/v5/launches/latest
    • Docs: SpaceX API
  14. Fun Translations
    • Yoda, Pirate, etc.
    • Endpoint: https://api.funtranslations.com/translate/yoda.json?text=Master%20this%20API%20you%20will.
    • Docs: Fun Translations
  15. Public Holiday API
    • Worldwide holidays
    • Endpoint: https://date.nager.at/api/v3/PublicHolidays/2024/US
    • Docs: Nager.Date
  16. Open Brewery DB
    • Breweries in the US
    • Endpoint: https://api.openbrewerydb.org/breweries
    • Docs: Open Brewery DB
  17. Harvard Art Museums API
    • Requires free API key
    • Endpoint: https://api.harvardartmuseums.org/object?apikey=DEMO_KEY
    • Docs: Harvard Art API
  18. JSONPlaceholder
    • Fake posts/users
    • Endpoint: https://jsonplaceholder.typicode.com/posts
    • Docs: JSONPlaceholder
  19. World Time API
    • Endpoint: http://worldtimeapi.org/api/timezone/Europe/London
    • Docs: WorldTimeAPI
  20. Meteostat
    • Weather history
    • Endpoint: https://meteostat.p.rapidapi.com/stations/nearby?lat=50.0&lon=10.0
    • Docs: Meteostat Docs

APIs With Basic Auth (10 Examples)

(You’ll get to practice setting username & password in API Parser)

  1. ReqRes (User simulation, Basic Auth supported)
    • Endpoint: https://reqres.in/api/users
    • Docs: ReqRes Docs
  2. httpbin Basic Auth
    • Endpoint: https://httpbin.org/basic-auth/user/passwd
    • Docs: httpbin Auth
  3. DigiCert CertCentral
    • Certificate management
    • Endpoint: https://www.digicert.com/services/v2/user/me
    • Docs: DigiCert API
  4. Bitbucket API
    • Code repo info, supports Basic Auth
    • Endpoint: https://api.bitbucket.org/2.0/repositories?role=member
    • Docs: Bitbucket API
  5. Mailtrap Email Testing
    • Send/receive test emails
    • Endpoint: https://mailtrap.io/api/accounts
    • Docs: Mailtrap API
  6. Jenkins API
    • CI/CD automation
    • Endpoint: http://your-jenkins.com/api/json
    • Docs: Jenkins API
  7. Buildkite API
    • CI service
    • Endpoint: https://api.buildkite.com/v2/user
    • Docs: Buildkite API
  8. CircleCI API
    • CI/CD, supports Basic Auth
    • Endpoint: https://circleci.com/api/v1.1/projects
    • Docs: CircleCI API
  9. ZoomEye (cybersecurity search)
    • Endpoint: https://api.zoomeye.org/user/login
    • Docs: ZoomEye Docs
  10. ElasticSearch
    • When self-hosted with Basic Auth
    • Endpoint: http://localhost:9200/_cat/indices?v
    • Docs: Elasticsearch REST

APIs With OAuth (5+ Examples)

  1. GitHub API
    • OAuth supported
    • Endpoint: https://api.github.com/user/repos
    • Docs: GitHub OAuth
  2. Twitter API (X)
    • OAuth 2.0 required for new apps
    • Endpoint: https://api.twitter.com/2/tweets
    • Docs: Twitter API
  3. Spotify API
    • Music data, OAuth required
    • Endpoint: https://api.spotify.com/v1/me/top/artists
    • Docs: Spotify Auth
  4. Google Calendar API
    • OAuth
    • Endpoint: https://www.googleapis.com/calendar/v3/users/me/calendarList
    • Docs: Google Calendar Auth
  5. Reddit API
    • OAuth
    • Endpoint: https://oauth.reddit.com/api/v1/me
    • Docs: Reddit OAuth
  6. Microsoft Graph API
    • OAuth, for Office 365 data
    • Endpoint: https://graph.microsoft.com/v1.0/me
    • Docs: MS Graph Auth

More Useful Free APIs

  1. Polygon.io (Crypto, Stocks—free tier)
    • Endpoint: https://api.polygon.io/v2/aggs/ticker/X:BTCUSD/range/1/day/2024-01-01/2024-01-31?apiKey=YOUR_KEY
    • Docs: Polygon Crypto
  2. Alpha Vantage (Crypto/Stock)
    • Free API Key needed
    • Endpoint: https://www.alphavantage.co/query?function=CURRENCY_EXCHANGE_RATE&from_currency=BTC&to_currency=USD&apikey=demo
    • Docs: Alpha Vantage
  3. Finnhub (Stocks, Crypto, News—free tier)
    • Endpoint: https://finnhub.io/api/v1/crypto/symbol?exchange=binance&token=YOUR_TOKEN
    • Docs: Finnhub API
  4. CoinCap (Crypto Data)
    • Endpoint: https://api.coincap.io/v2/assets/bitcoin
    • Docs: CoinCap API

How to Automate Data Syncs With API Parser Scheduler

  • After connecting your chosen API, use the API Parser Scheduler to run imports automatically—every hour, day, or week.
  • Perfect for tracking crypto prices, stock changes, or any live data feed.
  • Just set your schedule in the API Parser add-on and let it run!

Conclusion: Start Testing, Automating, and Innovating

Free testing APIs are a game-changer for developers, analysts, and marketers. With this list of 40 varied APIs, you can connect to everything from crypto prices to business services—all within your Google Sheet.

Using API Parser, you can:

  • Import any REST API (even those with Basic Auth or OAuth!)
  • Automate data refreshes with the built-in scheduler
  • Build live dashboards or automate business logic without writing code

Ready to supercharge your Sheets? Try API Parser with any of these APIs and see the power for yourself!

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