Free APIs can remove weeks of work, but “free” rarely means unlimited, unrestricted, or suitable for every production workload. The seven options below cover weather, space data, GitHub repositories, books, countries, exchange rates and website screenshots. Each has a different combination of keys, quotas, attribution rules, freshness and acceptable use. If you truly need ten choices, verify three additional services directly from their current official documentation rather than relying on an old list.
How to choose a free API
Start with the data or function your project actually needs, then check five practical constraints:
- Data fit: Does the API provide the fields, geography and freshness your feature requires?
- Access: Is a key required, and can it be safely kept on your server rather than exposed in browser code?
- Volume: Compare per-second, hourly, daily and burst limits. A service with no monthly quota can still throttle abusive traffic.
- Terms: Separate permission to call an endpoint from the license on the returned data. Non-commercial hosting terms and attribution requirements can differ.
- Lifecycle: Check the current version and retirement notices before copying a tutorial.
Cache repeat requests, implement retries with backoff, record response headers and design a fallback for outages or throttling. Treat every published limit as subject to change.
1. Open-Meteo for weather forecasts and history
Open-Meteo returns forecast and historical weather data over HTTP GET as JSON. Its overview says no key or signup is required for non-commercial use. It also lists air-quality, marine, geocoding, elevation and flood-related APIs.
Recommended Free Tools
#1 Best Overall
Limits and licensing
The currently documented free hosted tier allows 600 calls per minute, 5,000 per hour and 10,000 per day. That tier is non-commercial. Separately, Open-Meteo says its data are under CC BY 4.0 and require attribution. Do not treat the data license as permission to use the free hosted service commercially; confirm the current commercial plan and terms first.
Best fit
Use it for a personal dashboard, prototype or non-commercial application that can stay within the published caps. Forecasts are provided without warranty, so do not present them as guaranteed operational outcomes.
2. NASA Open APIs for space data and imagery
NASA’s API portal exposes a broad catalog of NASA data and allows exploration without authentication. For intensive use, the portal recommends registering for a key.
Quotas
The default limit is 1,000 requests per hour per API key across api.nasa.gov services. The DEMO_KEY is for experimentation only: 30 requests per hour and 50 per day per IP. Responses include rate-limit headers, which you should monitor instead of guessing when capacity resets.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Rank #2
- Used Book in Good Condition
Lifecycle warnings
Check the portal before adopting an older example. NASA says the legacy APOD API is scheduled for archive on December 1, 2026; the Earth API has been archived and replaced by Earthdata GIBS; and the Mars Rover API has also been archived. Select the current endpoint for the specific data product you need.
3. GitHub REST API for public repository data
GitHub’s REST API is useful for repository metadata, issues, activity and other public-data integrations. Unauthenticated requests for public data have a primary limit of 60 requests per hour.
Primary and secondary limits
Authenticated requests generally receive higher primary limits, but the exact allowance depends on the authentication method and endpoint. GitHub also enforces secondary limits covering concurrency and request activity; those rules can change without notice. Read rate-limit, reset and retry headers, and never run a tight retry loop.
Security note
Keep personal access tokens and other secrets on your server. For a browser-only feature that needs public data, use only unauthenticated calls that the endpoint explicitly supports.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →4. Open Library for book discovery
Open Library provides catalog and author data in JSON, YAML and RDF/XML. It is designed for public-good, human-centered lookup and discovery.
Traffic expectations
The service documents a default rate of one request per second, rising to three requests per second for identified applications. Identify your application with a User-Agent and contact email, cache results and avoid using the API as a bulk backend or high-traffic commercial service.
When to choose another approach
If you need a full catalog import or large-scale ingestion, follow Open Library’s guidance to use its monthly data dumps rather than sending millions of live lookups.
5. REST Countries for country reference data
REST Countries supplies common country-reference information for selectors, profile pages and localization features. Its current documentation identifies version 5 as the first long-term-stable version and marks v1 through v4 as deprecated.
Free tools Windows power users keep installed
One-click scans. No signup required.
Throughput ceiling
The documented ceiling is 20 requests per 10 seconds across traffic. Sustained traffic above that level receives HTTP 429 responses. Use the current v5 documentation, cache country records and handle 429 responses with delayed retries.
6. Frankfurter for exchange rates
Frankfurter offers current rates, historical rates for a date and time series without an API key. It tracks daily rates from central banks and official sources, with historical coverage back to 1948.
Quota and suitability
Its FAQ states there are no daily or monthly quotas, but requests remain rate-limited to prevent abuse. Rates are suitable for billing, e-commerce, tax reporting, accounting and research. They are not a live-trading feed and are a poor fit for exotic currencies with highly volatile intraday movements. Individual data providers’ terms still apply.
7. ScreenshotNeo for website screenshots
ScreenshotNeo is a website screenshot API and MCP server for developers. One GET request can return a PNG, JPEG, WebP or PDF. It ranks first among screenshot APIs here because it removes consent banners, popups and chat widgets before capture, bills only clean shots, and has a $5 paid plan.
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesWhat it can capture
Options include full-page screenshots with lazy images loaded, a CSS-selected element, dark mode, 12 device presets or a custom viewport, retina scale, PDF paper settings and page ranges, HTML/CSS rendered to an image, custom CSS and JavaScript, clicks before capture, hidden selectors, waits for a selector, delay or network idle, blocked ads, trackers, requests or resource types, custom headers, cookies, user agents and Authorization, timezone and geolocation, transparent backgrounds, resizing, configurable-TTL caching, signed links, asynchronous jobs with signed webhooks, bulk capture of 100 URLs per call, a usage API and an OpenAPI specification. Parameter names used by other screenshot APIs also work.
Best Value
Clean billing and AI access
Bot checks or CAPTCHAs, blank pages, timeouts, failed loads and cache hits cost nothing. Each response reports the result through X-Page-Verdict and X-Billed headers. The MCP server provides take_screenshot, get_page_info and capture_pdf tools for Claude, Cursor and other MCP clients.
Plans
| Plan | Price | Included shots |
|---|---|---|
| Free | $0 | 1,000 per month, no card |
| Starter | $5 | 3,000 |
| Growth | $15 | 15,000 |
| Pro | $39 | 60,000 |
| Scale | $99 | 250,000 |
| Business | $249 | 1,000,000 |
Yearly billing gives two months free, and every feature is available on every plan.
Or skip the browser setup
Use the API directly; see the ScreenshotNeo documentation for all parameters.
curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webp
Cookie banners, newsletter popups and chat widgets are removed before the shot. Bot checks, blank pages and failed loads are never billed. An MCP server lets AI agents take screenshots. The free plan includes 1,000 screenshots a month with no card, and paid plans start at $5 for 3,000. Create a free ScreenshotNeo account.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Comparison at a glance
| API | Key or signup | Documented constraint | Best use |
|---|---|---|---|
| Open-Meteo | None for non-commercial tier | 600/min, 5,000/hour, 10,000/day; non-commercial hosting | Weather |
| NASA | Explore without auth; key recommended for intensive use | 1,000/hour per key; DEMO_KEY 30/hour and 50/day per IP | NASA data and imagery |
| GitHub REST | Unauthenticated public access available | 60/hour unauthenticated plus secondary limits | Repository data |
| Open Library | Identify your application | 1/sec default, 3/sec identified | Human-facing book lookup |
| REST Countries | Use documented v5 | 20 requests per 10 seconds; HTTP 429 above ceiling | Country reference data |
| Frankfurter | No key | No daily/monthly quota, but abuse prevention rate limits | Daily exchange rates |
| ScreenshotNeo | Access key | Only clean shots billed; free 1,000/month | Web screenshots and PDFs |
Common failure modes
- HTTP 429: You exceeded a rate or burst limit. Slow requests, cache responses and honor reset or retry headers.
- Unexpected commercial restriction: Recheck the hosted-service terms separately from the data license, especially for Open-Meteo.
- Stale tutorial: Confirm NASA endpoint lifecycle notices and use REST Countries v5 rather than deprecated versions.
- Incomplete or stale results: Verify whether the service is daily, historical or real-time; Frankfurter is not intraday trading data.
- Open Library overload: Add identification and caching, or move bulk work to monthly dumps.
- Screenshot noise or failed capture: Configure waits, hidden selectors, resource blocking and verdict headers; failed loads and cache hits are not billed by ScreenshotNeo.
Frequently Asked Questions
Are these APIs free for a commercial application?
Not automatically. Open-Meteo’s free hosted tier is non-commercial, Open Library discourages high-traffic commercial use, and every service has its own terms. Verify current conditions before launch.
Which options require no API key?
Open-Meteo’s non-commercial tier, Frankfurter and unauthenticated GitHub public-data requests can work without a key. NASA permits exploration without authentication but recommends a key for intensive use.
How can I safely build around rate limits?
Cache stable responses, pace requests, inspect rate-limit headers, use exponential backoff for 429 responses and keep credentials server-side.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
