Nationalize.io
Nationalize.io is a name-to-nationality prediction API that estimates the national origin of a person from their first name, based on statistical analysis of the frequency with which names appear in different countries. The API takes a first name and returns a ranked list of countries with their estimated probability — reflecting how strongly that name is associated with each nationality in the reference dataset.
The prediction methodology is frequency-based: the API analyzes how often a given name appears in user profiles, census records, and social network data attributed to each country, then calculates the probability distribution across countries. A name that is very common in one country and rare elsewhere produces a high-probability single-country result. A name that is common across many countries produces a spread distribution with lower probabilities for each country.
Multiple countries are returned per name because many names are genuinely multinational — international names like "Mohammed" are very common across many Muslim-majority countries, while others may be dominant in two or three adjacent countries. The probability distribution enables applications to handle these ambiguous cases, using the highest-probability country as the primary prediction while acknowledging alternative possibilities.
ISO 3166 country codes are used in the response, enabling clean integration with other country-data systems such as geographic mapping, localization libraries, and regional classification tools. The response also includes the total sample count used for the prediction, providing context for the confidence of the result.
Batch lookup mode allows multiple names to be submitted in a single API request, which is efficient for processing entire user databases or contact lists without per-name API call overhead.
For Nigerian businesses and applications with international user bases or diaspora audiences, Nationalize.io provides a valuable data enrichment capability. Nigerian fintech apps, e-commerce platforms, and digital services that serve both Nigerian domestic users and Nigerian diaspora globally can use nationality prediction from names to segment their audiences — offering Nigeria-specific products and promotions to likely Nigerian users while presenting international offerings to users predicted to be from other countries.
Nigerian platforms building audience analytics and market intelligence tools can use Nationalize.io to characterize the geographic diversity of their user base from name patterns, supplementing or replacing explicit nationality data collection in contexts where asking for nationality might increase registration friction.
Like its sister APIs Genderize.io and Agify.io, Nationalize.io offers a free tier of 100 predictions per day without requiring an API key — making evaluation completely frictionless. Paid tiers at $9/month and $29/month scale to millions of predictions, appropriate for large-scale data enrichment. The REST API requires a simple GET request with the name as a query parameter.
Nationalize.io's data is derived from real-world name distributions rather than cultural assumptions, meaning it reflects actual usage patterns rather than theoretical origins. A name that was historically specific to one country but has spread globally through migration and cultural exchange will show a distributed probability across its current usage countries — giving a more accurate picture of how names actually map to nationalities in the modern global population. This is particularly relevant for Nigerian names that have spread internationally through the Nigerian diaspora.