If you're building scheduling software, payroll systems, or anything that needs to know when people aren't working, you need a holiday API. The problem? There are at least seven options worth considering, and they differ in ways that matter.

This guide breaks down what each API actually offers, where they fall short, and which one makes sense for your specific situation.

Before we dive into the comparison, it's worth understanding why this problem is harder than it seems:

• Holidays move. Easter, Eid, Chinese New Year, and dozens of others shift dates every year.

• Regions matter. The US has federal holidays, but individual states add their own. Germany has 16 states with different holiday calendars.

• Lunar calendars are complex. Islamic holidays depend on moon sightings and can vary by country. Getting these right requires specialized data.

• Business days aren't just "not holidays." You need to account for weekends (which vary by country), half-days, and regional observances.

With that context, let's look at your options.

Price: $100/year | Countries: 230+

Calendarific is the workhorse option. It covers more countries than most alternatives and handles the complexity of regional holidays well. You get public holidays, observances, and religious holidays in a clean REST API.

Strengths:

• Broad country and regional coverage

• Handles Islamic/lunar holidays with country-specific variations

• Straightforward JSON responses

• Solid documentation

Weaknesses:

• No business day calculations—you get holidays, but calculating "next business day" is on you

• No free tier beyond a limited trial

• Historical data only goes back a few years on lower plans

Best for: Teams that need reliable global coverage and can handle business day logic themselves.

Price: $99–$999/year | Countries: 230+

TimeAndDate is the reference-grade option. They've been tracking time and date data for decades, and it shows in their historical coverage. If you need to know what holidays were observed in Brazil in 1987, this is your API.

Strengths:

• Deep historical data (decades, not just years)

• Highly accurate lunar calendar handling

• Trusted by enterprise clients

• Includes sunrise/sunset and other time data if you need it

Weaknesses:

• Pricing scales steeply with usage

• API design feels dated compared to newer options

• Overkill if you only need current/future holidays

• No built-in business day calculations

Best for: Enterprise applications needing historical accuracy or integration with other time-based data.

Price: $9–$99/month | Countries: 200+

Abstract offers a holiday API as part of their broader API suite (which includes email validation, IP geolocation, and more). The holiday data is solid, and the developer experience is polished.

Strengths:

• Modern, well-documented API

• Part of a suite—convenient if you need other APIs

• SOC 2 Type II compliant

Weaknesses:

• Free tier is only 1,000 requests total (not per month), and prohibits commercial use

• Paid tier jumps straight to $99/month—no mid-tier option

• Country coverage slightly less comprehensive than Calendarific

• No business day endpoint

• Lunar holiday handling is less nuanced

Best for: Developers already using Abstract's other APIs, or those who prefer monthly billing.

Price: Free (open source) | Countries: ~119

Nager.Date is the open-source champion. It's free, well-maintained, and covers most of Europe thoroughly. If your users are primarily in Europe and North America, this might be all you need.

Strengths:

• Completely free

• Open source—you can self-host or contribute fixes

• Excellent European coverage (regional holidays for Germany, Austria, Switzerland, etc.)

• Includes a basic business day calculation endpoint

Weaknesses:

• Limited coverage in Asia, Africa, and South America

• Explicitly excludes all Islamic holidays (Eid al-Fitr, Eid al-Adha, etc.)

• Smaller team maintaining it (bus factor risk)

• Offline use (NuGet/Docker) requires GitHub sponsorship

Best for: Projects focused on Europe/North America, budget-conscious teams, or anyone who wants to self-host.

Price: Freemium (free tier + paid plans) | Countries: 100+

HolidayAPI has been around for years and offers a straightforward freemium model. The free tier is limited to historical data, which is an unusual restriction.

Strengths:

• Free tier available

• Simple, easy-to-use API

• Covers major countries well

Weaknesses:

• Free tier only returns previous year's holidays (not current or future)

• Country coverage is narrower than Calendarific or TimeAndDate

• Regional holiday support is inconsistent

• Documentation is sparse in places

Best for: Hobby projects or prototypes where you don't mind the historical-only limitation on free tier.

Price: Free (open source) | Countries: 36

OpenHolidays is a newer open-source project with a focus on accuracy over breadth. It covers fewer countries but aims to get every detail right for the ones it does cover.

Strengths:

• Completely free and open source (AGPL-3.0)

• Includes school holidays (unique among free options)

• High accuracy for supported countries

• JSON and iCal formats

Weaknesses:

• Limited to 36 countries (European focus + Brazil, Mexico, South Africa)

• Data only available from 2020 onwards

• No Islamic/lunar holiday support

• No business day calculations

• Not suitable for global applications

Best for: European-focused projects that prioritize data accuracy over breadth, or need school holiday data.

Price: $79/year | Countries: 230+

World Data API bundles holidays with business day calculations and other date-related utilities. It's one of the few options that answers "is this a business day?" directly.

Strengths:

• Built-in business day calculations

• Broad country coverage

• Includes related data (country info, currencies, etc.)

• Competitive annual pricing

Weaknesses:

• Less established than Calendarific or TimeAndDate

• Documentation could be more detailed

• Lunar holiday handling varies by country

• Smaller community (fewer Stack Overflow answers when you get stuck)

Best for: Applications that need business day logic built in, especially payroll or scheduling systems.

All of these APIs occasionally have errors—holidays get added late, regional observances get missed, or lunar calculations differ from official announcements.

In our experience, TimeAndDate and Calendarific have the best track records for accuracy. Nager.Date and OpenHolidays benefit from open-source corrections but can lag on less common countries. The others fall somewhere in between.

If accuracy is critical (think: payroll compliance), budget for validation against official government sources for your key markets.

Go with Calendarific. It's $100/year, covers 230+ countries, and just works. You'll need to build business day logic yourself, but the holiday data is reliable.

Start with Nager.Date. It's free, covers Europe thoroughly, and includes basic business day calculations. If you outgrow it, migrate to Calendarific later.

Choose World Data API. At $79/year with built-in business day endpoints, it saves you from implementing that logic yourself. Nager.Date is a free alternative if you're Europe-focused.

Use Nager.Date or OpenHolidays. Both are free and open source. Nager.Date has broader coverage; OpenHolidays has higher accuracy for its supported countries.

TimeAndDate is your only real option. They have the deepest historical archives. Expect to pay for it.

Add Abstract Holidays for convenience. The bundled pricing and consistent API design make sense if you're already in their ecosystem. Just watch the monthly costs.

TimeAndDate handles this best, followed by Calendarific. Lunar holidays vary by country based on moon sighting committees, and these two track those variations most reliably.

There's no single "best" holiday API—it depends on your coverage needs, budget, and whether you need business day calculations built in.

If you're unsure, start with Nager.Date (free) to validate your approach, then upgrade to Calendarific ($100/year) or World Data API ($79/year) when you need broader coverage or business day logic.

And whatever you choose, build in a fallback. Holiday APIs occasionally go down or return unexpected data. Cache aggressively, validate edge cases, and your users will never know the difference.