12 Best APIs for Calendar in Nigeria

REST Countries is a free, open-source API providing comprehensive metadata for every country in the world. Without requiring an API key, account registration, or any authentication, the API returns structured data including official names, ISO country codes, capital cities, currencies, languages, calling codes, flag images (SVG and PNG), geographic coordinates, population, land area, timezones, bordering countries, and regional classifications for all 250 sovereign nations and territories globally — including Nigeria with complete data. For Nigerian developers, REST Countries is a utility API that solves several common frontend and backend development problems that arise when building applications serving multiple countries or needing to display country-related information. The API is CORS-enabled, meaning it can be called directly from browser JavaScript without a backend proxy, and responses are typically fast as the dataset is small and entirely static in nature. Nigeria's data in REST Countries includes: official name "Federal Republic of Nigeria", common name "Nigeria", ISO codes (NG / NGA / 566), capital Lagos (though Abuja is the official capital — a common data quality issue worth noting), currency Nigerian Naira (NGN) with symbol ₦, official languages (English), calling code +234, flag SVG and PNG images, continent Africa, region West Africa, subregion Western Africa, population approximately 218 million, land area 923,768 km², coordinates for geographic center, UTC+1 timezone, and bordering countries (Benin, Cameroon, Chad, Niger). The most common use cases in Nigerian application development are: populating country dropdowns in registration and address forms; displaying calling code prefixes in phone number inputs (pre-selecting +234 for Nigerian users); showing currency symbols alongside amounts on multi-currency platforms; displaying country flags in language selectors or international features; and providing educational content about world countries. For country selector dropdowns in Nigerian application registration forms, REST Countries provides clean, consistent country names and codes that eliminate the need to maintain a custom country list. Developers fetch the country list once from the API (or bundle it at build time) and render a searchable select input. With IP geolocation (via a service like GeoJS or IPinfo), Nigeria can be automatically pre-selected as the default country for Nigerian users. Flag images are served as SVG (vector, infinitely scalable) and PNG (raster, width-specified). The flag image URLs pointing to flagcdn.com can be embedded directly in img tags or used as CSS background images. For Nigerian financial and travel applications that display flags alongside country names for currencies or destinations, REST Countries provides a consistent source of all 250 country flags without hosting assets locally. The API supports multiple search modes: get all countries, get by full name, get by partial name, get by ISO code (alpha-2 or alpha-3 or numeric), get by calling code, get by capital, get by currency, get by language, and get by region. This flexibility means applications can query countries by any attribute — for example, fetching all West African countries, or finding the country using "NGN" as currency, or looking up all countries that speak French. REST Countries is maintained as an open-source project on GitHub. Because it is a static dataset that changes infrequently (country data is stable — new countries are extremely rare), the data can also be cached aggressively or bundled directly into an application at build time, eliminating network requests entirely. Several npm packages bundle the REST Countries data for offline use, which is particularly useful for Nigerian mobile applications that should function correctly without internet connectivity. The API has been widely used by Nigerian developers in bootcamp projects, hackathon submissions, and production applications for years, and the dataset quality for Nigerian data (country code, currency, flag) is reliable for all fields except the capital (which lists Lagos rather than Abuja in some responses — a known data discrepancy that developers should handle explicitly).

Holidays API by Holidays API (holidaysapi.com) is a comprehensive public holiday data service providing programmatic access to historical and upcoming public holidays for over 200 countries and territories, covering national holidays, regional observances, and religious celebrations from 2015 onward. For Nigerian developers building scheduling applications, payroll systems, HR software, or any calendar-aware tool, the Holidays API provides structured holiday data for Nigeria's statutory public holidays alongside comprehensive global coverage — enabling applications that must handle public holidays across multiple countries. Nigeria's public holidays covered by the Holidays API include the 12 statutory national holidays recognized by the Federal Government: New Year's Day (January 1), Democracy Day (June 12), Independence Day (October 1), Christmas Day (December 25), Boxing Day (December 26), Good Friday, Easter Monday, Eid al-Fitr (2 days), Eid al-Adha (1 day), Id el Maulud (Mawlid an-Nabi), and Workers Day (May 1). The moveable holidays — Easter and the Islamic observances — are calculated per year based on the lunar calendar, and Holidays API provides the correct dates for each year in its database. Payroll automation using the Holidays API is one of the most direct use cases for Nigerian businesses. Payroll software must correctly identify which days in a given month are working days versus public holidays to calculate statutory pay, overtime rates, and payment run timing. By querying the Holidays API at the start of each year, Nigerian payroll systems can populate their holiday calendars with accurate dates for all 12 national holidays — including the exact dates for Easter and Islamic holidays — without manual data entry that risks errors. HR leave management systems benefit from accurate public holiday data for calculating available leave days, processing leave applications that overlap with public holidays, and ensuring statutory holidays are correctly excluded from annual leave counts. Nigerian HR platforms serving companies across multiple states should note that some Nigerian states observe additional state-level public holidays beyond the national list — though the Holidays API covers national holidays primarily. Multi-country scheduling for Nigerian businesses with international operations is streamlined by Holidays API's 200+ country coverage. A Nigerian company scheduling meetings with partners in the US, UK, and Germany can query all three countries' holiday calendars simultaneously to identify dates when all parties are working — avoiding the manual research of each country's public holiday schedule that is otherwise required. Content calendar planning for Nigerian digital agencies and marketing teams uses public holiday data to identify themed content opportunities. Nigerian national holidays like Independence Day on October 1 or Democracy Day on June 12 are high-engagement content moments that Nigerian brands reliably target with special campaigns, social media posts, and promotional offers. Automated content calendar tools can pull Holidays API data to pre-populate the editorial calendar with upcoming public holidays as content planning reminders. The Holidays API operates on a freemium model with a free tier providing access to historical holiday data from 2015 through the previous year. Accessing current year or future year holidays requires a paid subscription starting at around $19/year — making it one of the most affordable commercial holiday APIs available for Nigerian app developers. The Holidays API historical data archive from 2015 makes it one of the longest-available datasets for auditing past payroll or scheduling decisions against actual Nigerian public holiday dates.

Timeanddate Public Holidays API provides access to the comprehensive public holiday and observance database maintained by timeanddate.com — one of the world's most trusted sources for time zone, calendar, and astronomical data, operating since 1995. The Timeanddate holidays dataset covers over 230 countries and territories with exceptional accuracy, including Nigeria's national public holidays with correct dates for moveable feasts like Easter and Islamic holidays calculated for each year. For Nigerian businesses and developers who need authoritative, accurate holiday data backed by decades of calendar expertise, Timeanddate is one of the most reliable sources available. The Timeanddate holiday API returns structured data for each public holiday: the holiday name, date, type (national, observance, religious), and description. For Nigerian holidays, this includes the statutory national holidays plus major religious observances: New Year's Day, Workers Day (May 1), Democracy Day (June 12), Independence Day (October 1), Christmas Day, Boxing Day, Good Friday, Easter Monday, Eid al-Fitr, Eid al-Adha, and Mawlid al-Nabi. The religious holidays are returned with the year-specific dates computed by Timeanddate's calendar calculation system, which has a long track record of accuracy. Business day calculation using Timeanddate holiday data is a critical function for Nigerian financial services and legal technology. Loan processing timelines specified in "business days," contract cooling-off periods, regulatory filing deadlines, and legal notice periods all require accurate knowledge of which days are public holidays in Nigeria. A fintech platform promising a 3-business-day loan disbursement needs to correctly skip public holidays in that calculation — using Timeanddate's authoritative holiday data ensures the calculation is defensible and accurate. International scheduling across time zones and holiday calendars is a strength of Timeanddate's integrated platform. The Timeanddate API includes both time zone and holiday data, enabling Nigerian companies coordinating with international counterparts to check simultaneously whether a proposed meeting date conflicts with any party's public holiday, and to convert the proposed time to each party's local time zone. For Nigerian professional services firms, consulting companies, and tech companies with international clients, this integrated time zone and holiday functionality simplifies scheduling workflows. Sun and moon calculations from Timeanddate (available in related API products) include sunrise, sunset, moonrise, moonset, and moon phase data — useful for Nigerian agricultural apps planning outdoor activities around daylight hours, Nigerian security platforms scheduling outdoor operations, and Nigerian event planners arranging outdoor events around natural light. The Timeanddate API is commercially licensed through a subscription model, with pricing that reflects the premium quality and reliability of the underlying data. For Nigerian businesses building compliance-sensitive applications where incorrect holiday dates could cause regulatory violations, missed deadlines, or customer complaints, the Timeanddate commercial license with its data accuracy guarantee is worth the investment. API access uses standard REST calls with API key authentication, returning JSON responses. The Timeanddate developer documentation is comprehensive, covering all endpoint parameters, response formats, and country codes. Nigerian developers integrating Timeanddate holiday data can expect well-maintained documentation and a stable API suitable for production use in business-critical scheduling applications.

Easter Date API provides a simple, free endpoint for calculating the date of Easter Sunday for any given year, supporting both the Western (Gregorian) Easter calculation used by Roman Catholic and Protestant churches and the Eastern (Julian) Easter calculation used by Eastern Orthodox churches. Easter is a moveable feast that falls on a different date each year based on a calculation involving the spring equinox and lunar calendar, making programmatic calculation a practical need for app developers building religious calendar apps, church management systems, or any calendar application that needs to account for Easter-dependent holidays. The Western Easter algorithm implemented by this API follows the calculation defined by the Gregorian calendar reform, producing the date on which Easter falls for Catholic and Protestant denominations — the Sunday after the first full moon on or after the vernal equinox (March 21). For Nigerian Christian app developers building church management software or religious calendar apps for Catholic, Anglican, Baptist, Methodist, Assemblies of God, or other mainstream Christian denominations (which together constitute the majority of Nigeria's southern Christian population), the Western Easter date is the relevant calculation. Easter-derived dates are also computable once the Easter date is known: Ash Wednesday falls 46 days before Easter; Palm Sunday is the Sunday before Easter (6 days prior); Holy Thursday (Maundy Thursday) is 3 days before Easter; Good Friday is 2 days before Easter; and Pentecost Sunday falls 49 days after Easter. Nigerian church calendar apps that need to display the full Holy Week schedule and the date of Pentecost each year can calculate all these dates programmatically starting from the Easter date returned by this API. Public holiday calculation in Nigeria includes Easter-adjacent days. Good Friday is a public holiday in Nigeria, as is Easter Monday. App developers building Nigerian public holiday calendars, HR management systems, or payroll applications that need to account for Easter-linked holidays can use this API to dynamically determine Good Friday and Easter Monday dates rather than hardcoding them. This is particularly useful for multi-year payroll or scheduling systems that need accurate holiday dates years in advance. Eastern Orthodox Easter (Pascha) calculation is also supported, returning the Easter date according to the Julian calendar calculation used by the Greek Orthodox, Russian Orthodox, Serbian Orthodox, Romanian Orthodox, and other Eastern churches. While the Eastern Orthodox community is small in Nigeria, international businesses operating in Nigeria with Orthodox staff, or Nigerian-diaspora-focused apps, may require this calculation. The API accepts a year as a query parameter and returns the Easter date in standard ISO 8601 format, making integration straightforward in any programming language or framework. Nigerian developers using JavaScript, Python, PHP, or any other common language can integrate the Easter Date API in minutes. The endpoint is free with no authentication required, no rate limits documented, and returns a simple JSON response with the calculated date, making it one of the simplest religious calendar APIs available for Nigerian Christian app development projects. School management systems in Nigerian private Christian schools can use the Easter Date API to automatically populate the school calendar with holiday dates each academic year — removing the risk of a school secretary miscalculating Easter and scheduling classes on Good Friday. Payroll software vendors serving Nigerian companies can integrate this API to dynamically compute Easter-linked public holidays for each year when processing payroll calendars. The API response is minimal and fast, returning only the computed date in a clean JSON structure, making it one of the most lightweight religious calendar API integrations available to Nigerian developers building feature-rich but performant applications.

Abstract Holidays API is a clean, developer-friendly public holiday data API offered by AbstractAPI — a company known for building simple, well-documented API products for common developer tasks. The Abstract Holidays API provides national public holiday data for 200+ countries with straightforward API design: a single endpoint, simple API key authentication, and clean JSON responses that make integration quick and the data immediately usable. For Nigerian developers who want a polished, modern API experience for holiday data without the complexity of larger API platforms, Abstract Holidays is one of the most accessible entry points to global public holiday data. Country holiday data retrieval from the Abstract Holidays API is straightforward: pass the country code (NG for Nigeria), year, and API key, and receive a JSON array of public holidays for Nigeria in that year. Each holiday object includes the name, name in the local language, date in YYYY-MM-DD format, day of the week, type (national or observed), and a description where available. This clean, consistent response format is easy to parse and display in any Nigerian application regardless of the programming language or framework being used. Nigeria coverage in the Abstract Holidays API includes all federal public holidays, with moveable holidays like Easter and Islamic observances calculated for each requested year. Nigerian developers do not need to maintain a local database of holiday dates or write their own calendar calculation logic — querying the API with the year and country code returns the complete set of correctly dated Nigerian holidays for that year. Multiple country support in a single API account enables Nigerian businesses with international operations to retrieve holiday data for multiple countries using the same API key and endpoint, just changing the country code parameter. A Nigerian holding company with subsidiaries in Ghana, Kenya, and South Africa can build a multi-country holiday awareness system using Abstract Holidays without managing separate holiday data subscriptions for each market. Data freshness and accuracy from Abstract Holidays is maintained by the AbstractAPI team, who update holiday datasets when countries announce changes to their official public holiday schedules. Nigerian public holidays are occasionally modified by government proclamation (for example, a holiday may be moved to an adjacent Monday for a long weekend), and API-driven holiday data that is maintained by the provider requires fewer manual updates by Nigerian development teams than hardcoded holiday lists. The Abstract Holidays API is available on a freemium model — the free tier provides a limited number of API calls per month that is sufficient for small applications and development/testing. The free tier includes access to national holidays for all supported countries including Nigeria. Paid plans increase the monthly call limit for production applications with higher traffic, and pricing is affordable for individual Nigerian developers and small startups. Integration uses a single HTTP GET request with API key authentication via query parameter. The AbstractAPI documentation provides code examples in Python, Node.js, PHP, Ruby, and other languages. Nigerian developers can register for a free API key at abstractapi.com and make their first holiday API call within minutes, without setting up complex OAuth flows or SDK installations. AbstractAPI's consistent API design philosophy across its product suite means Nigerian developers familiar with other AbstractAPI products can onboard to Abstract Holidays with minimal learning curve. The same authentication pattern, response format conventions, and error handling approach used across all AbstractAPI products applies here, making multi-product AbstractAPI integrations efficient.

Open Holidays API is a free, open-source public holiday data API that provides community-maintained holiday datasets for multiple countries, accessible without any API key or authentication requirement. Built as a community project and hosted openly, Open Holidays API embodies the open-source ethos of freely available public data — holiday dates are public information, and Open Holidays makes them available as a clean REST API that any developer worldwide can use without registration or payment. For Nigerian developers building scheduling features, calendar tools, or public holiday awareness into their applications on a zero-budget basis, Open Holidays provides immediate, friction-free access to structured holiday data. The API returns holiday data by country code and year, providing the holiday name (in the country's language and optionally in English), date, and holiday type classification. For Nigeria (country code NG), the API returns the statutory national public holidays that apply across the country, giving Nigerian app developers the base dataset needed for business day calculations, payroll processing, and scheduling features without the cost of a commercial holiday API. Zero-authentication access is Open Holidays API's most developer-friendly characteristic. There is no API key to obtain, no registration form to complete, and no rate limit tied to an account — simply call the endpoint with the country code and year parameters and receive the holiday data. For Nigerian hackathon participants, side project developers, open-source contributors, and students learning API integration, this frictionless access makes Open Holidays the fastest way to get started with public holiday data. Open-source community model means that the holiday data is maintained by contributors around the world, with corrections and additions submitted through the project's repository. For countries with active communities, the coverage is excellent; for less-represented countries, accuracy should be verified against official government sources before using in compliance-sensitive production applications. Nigerian developers using Open Holidays for critical scheduling should cross-verify the Nigerian holiday dates against official Federal Government of Nigeria pronouncements, particularly for Islamic holidays whose dates are announced by the Sultanate each year. Cross-African scheduling support through Open Holidays covers multiple African countries, making it useful for pan-African applications that need holiday awareness across West Africa, East Africa, and Southern Africa simultaneously. Nigerian conglomerates with operations in Ghana, Kenya, and South Africa can query all three countries' holiday calendars from one API endpoint, supporting regional scheduling and operations coordination. Developer prototyping and teaching are ideal use cases for Open Holidays API. Nigerian coding bootcamps, universities teaching web development, and developers building proof-of-concept applications benefit from the ability to integrate real, live holiday data without any account setup — keeping the learning focus on integration patterns rather than on account management and API key provisioning. The Open Holidays API is hosted at openholidaysapi.org and is available completely free with no usage restrictions documented. The project is open-source and welcomes contributions to expand country coverage and improve data accuracy. Nigerian developers who identify inaccuracies in the Nigeria holiday dataset are encouraged to contribute corrections to the GitHub repository.