Find answers to our most frequent questions

Genderize is an API that predicts the gender of a person based on their first name. It uses a dataset of around a billion records to return a statistical probability — for example, that "Anna" is 97% likely to be female. You can try it instantly with no sign-up at api.genderize.io?name=anna.

Genderize, Agify, and Nationalize are all operated by Demografix ApS and share the same underlying dataset of ~1 billion records. A single subscription gives you access to all three APIs with one API key. You can predict gender, age, and nationality from names — separately or in combination.

Our APIs are used by academic researchers, data scientists, marketers, HR teams, journalists, and developers worldwide. Notable users include The Guardian, MIT, Columbia University, Yale University, Uber, Shopify, Nature, and The Washington Post. Genderize.io alone has been cited in over 1,400 academic papers.

Most first names are predominantly used by one gender. Genderize uses a statistical approach across a dataset of ~1 billion records to calculate the probability that a given name belongs to a male or female person. The API returns the predicted gender, a probability score (0 to 1), and a count of how many data rows were examined. Names that are used across both genders — like "Kim" or "Alex" — will return a probability closer to 0.5, reflecting genuine ambiguity.

Yes, and we recommend it whenever you have the data. Some names behave very differently across cultures — "Kim" is predominantly male in Denmark but predominantly female in the United States, and "Andrea" is a common male name in Italy but female in most English-speaking countries. Pass the country_id parameter (ISO 3166-1 alpha-2 code) to get predictions scoped to a specific country.

We recommend sending the first name only, as that gives the most accurate results for gender and age prediction. However, if you only have a full name, the API will attempt to parse out the first name automatically.

Yes. You can send up to 10 names per request using array syntax: name[]=anna&name[]=john&name[]=kim. Each name counts individually toward your usage limit.

The API attempts three lookup strategies in sequence: a direct match, a match with diacritics removed (e.g., "José" → "Jose"), and a parsed first/last name from a full name string. If no match is found after all three attempts, the prediction fields will be returned as null.

Our dataset consists of around a billion data rows covering 249 countries and territories. You can explore the full coverage breakdown on our Our Data page.

Our data is collected from publicly available sources across the web. We have been collecting and processing name-based demographic data for over 12 years.

Gender prediction is based on statistical probability. If a name returns a probability of 0.92 for female, it means 92% of the people with that name in our dataset are female. On an unbiased sample, the prediction will be correct at that same rate. When tested against the 2024 Olympic Athletes dataset (11,074 athletes), Genderize achieved 94.35% accuracy using first name with country scoping. Accuracy improves further when you scope predictions to a specific country, since names like "Andrea" or "Kim" behave differently across cultures.

Names like "Alex," "Jordan," or "Robin" are used by both genders. For these names, the probability score will be closer to 0.5, reflecting the genuine split in our dataset. This is useful information in itself — a probability of 0.52 tells you the name is essentially gender-neutral, which is a valid finding for many use cases.

Extensively. Genderize.io has been cited in over 1,400 scholarly articles across disciplines including sociology, computer science, economics, medicine, and media studies. You can find papers using Genderize.io on arXiv , Europe PMC , JAMA Network , Springer , and MDPI .

Yes. You can enrich CRM data with gender, age, and nationality predictions through our official no-code apps for Zapier, Make, and Pipedream . These integrations let you automatically process new contacts as they're added. For more custom setups, the API is straightforward to call from any CRM with webhook or API support.

Yes. We offer a CSV upload tool that lets you upload a spreadsheet and get predictions added as new columns. We also have official integrations with Zapier, Make, and Pipedream for no-code workflows.

The easiest way is through our official no-code apps for Zapier, Make, and Pipedream . These let you automatically classify customers by gender as they enter your system. For a more custom solution, you can call the Genderize API directly — it's a single HTTP call per name with no SDK required.

Yes. Our CSV tool lets you upload a spreadsheet with a name column and get a gender column added automatically. You can also set up automated spreadsheets that update gender when new rows are added — see our guide on checking gender in Google Sheets using Zapier .

Currently, Genderize provides binary (male/female) predictions based on the statistical distribution of names in our dataset. We do not directly address non-binary gender identities. If your use case requires sensitivity to non-binary genders, we recommend using the probability score to identify gender-neutral names (those with probabilities near 0.5) and treating them accordingly in your analysis.

We recommend that researchers: (1) clearly report their methodology, including which API and parameters were used, (2) acknowledge the limitations of name-based inference — it reflects statistical tendencies, not individual identity, (3) use our predictions as one component of a broader methodology rather than a sole determinant, and (4) be transparent about accuracy rates and how uncertain predictions were handled.

Ethics depend on context and application. Name-based gender classification can be a valuable tool for large-scale studies where individual-level data isn't available — for example, analyzing gender gaps in academic publishing or media representation. However, researchers should be transparent about the method's limitations, consider privacy implications, and ensure their use aligns with their institution's ethics guidelines.

Key limitations to be aware of: (1) gender prediction is binary and does not capture non-binary identities, (2) cultural biases may exist — predictions are only as representative as the underlying data, (3) some names are genuinely ambiguous and will yield low-confidence results, (4) predictions reflect population-level statistics, not individual certainty, and (5) the dataset may have uneven coverage across regions. We recommend using the probability score and count fields to assess confidence for each prediction.

Yes — you can make up to 100 requests per day with no sign-up and no API key. This free tier gives you access to all three APIs (Genderize, Agify, and Nationalize). If you need more, paid subscriptions start at $20/month for 25,000 names.

All paid plans include access to all three APIs (Genderize, Agify, and Nationalize) with a single API key. There is no rate limiting beyond your monthly name allowance. Plans range from 25,000 names/month ($20) to 25,000,000 names/month ($540). Annual billing saves you two months.

We count names, not API calls. If you send a batch of 100 names in a single request, that counts as 100 names against your monthly limit. A CSV upload with 10,000 rows counts as 10,000 names. One name in, one name counted — however you send it.

Requests above your limit return a 429 Too Many Requests response until your next billing cycle starts. We never charge overage fees and we'll never bill you for usage you didn't agree to. If you're consistently hitting the ceiling, upgrade to the next tier — it takes effect immediately.

Yes. Upgrades take effect immediately and we prorate the difference. Downgrades take effect at the start of your next billing cycle, so you keep the higher limit until then.

No. Limits reset at the start of each billing cycle.

Yearly billing costs the same as 10 months of monthly billing — you get two months free. You're charged once per year and your limit resets monthly as usual.

No. Your subscription stays at the price you signed up at for as long as you remain subscribed. If we raise prices, only new customers pay the new rate. Cancel and resubscribe later and you'll be on whatever the current pricing is at that point.

Yes. Cancel from your dashboard in one click. You keep access until the end of your current billing period, and we don't ask why or try to talk you out of it.

All major credit and debit cards, plus PayPal, processed through Stripe. For yearly Enterprise plans we also support invoicing and bank transfer.

We use Stripe as our payment provider. Your credit card details and billing information are stored with Stripe and never touch our systems.

Go to your account page and click "Billing dashboard" under the Billing management section. This takes you to Stripe's billing portal where you can update your details.

We cannot manually trigger a charge. Stripe will retry up to four times within two weeks. As long as a working payment method is on file before the last attempt, you'll be fine.

Sign up for a paid subscription on the registration page . Your API key will be available immediately in your account dashboard. For the free tier (100 names/day), no API key is needed.

Free users are limited to 100 requests per day. Paid subscribers have no rate limiting — you can make requests as fast as you need, up to your monthly name allowance.

You can reach us at info@genderize.io for any questions. We're happy to help you get the most out of our APIs, whether you need guidance on integration, data coverage, or choosing the right plan.

We do not store the names you submit via the API. Individual API requests are processed in real time and the names are immediately discarded — they are not written to any database, log, or file. For CSV file uploads, the original file is processed in memory only. The results file is stored temporarily and deleted after you download it or after 24 hours, whichever comes first. We do not log IP addresses of API requests.

Demografix ApS is a Danish company, directly subject to the GDPR. We practice data minimization by design: we don't store the names you submit, we don't log IP addresses, and our website analytics are cookieless. For full details, see our GDPR & Data Protection page and our Privacy Policy .

Yes. Our Data Processing Agreement is available and applies automatically through our Terms of Service. If your organization requires a countersigned copy, contact us at info@genderize.io .

Our infrastructure is hosted by DigitalOcean in the United States. For details on international data transfers and the safeguards in place, see our GDPR & Data Protection page.