FAQ

Find answers to our most frequent questions

About the service

  • What is Agify?

    Agify is an API that predicts the age of a person based on their first name. Names go through cycles of popularity, creating a statistical link between first names and likely birth years. For example, the name "Dorothy" skews significantly older than "Zoe." You can try it instantly with no sign-up at api.agify.io?name=dorothy.

  • How are the three APIs related?

    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.

  • Who uses these APIs?

    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.

How it works

  • How does age prediction work?

    Names go through cycles of popularity. "Harold" peaked decades ago, while "Liam" is popular today. This creates a statistical correlation between first names and birth years. Agify uses a dataset of ~1 billion records to estimate the most likely age of a person based on their first name. The API returns the predicted age as an integer and a count of how many data rows were examined.

  • Does specifying a country improve results?

    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.

  • What names should I send — first name or full name?

    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.

  • Can I send multiple names in one request?

    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.

  • What happens if a name isn't in your dataset?

    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.

Data & accuracy

  • How big is your dataset?

    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.

  • Where does the data come from?

    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.

  • How accurate is age prediction?

    Age prediction is inherently approximate — it estimates a statistical central tendency, not an exact birth year. The prediction is most useful for understanding the age profile of a name across a population, not for pinpointing an individual's age. Accuracy improves when you scope the prediction to a specific country using the country_id parameter, since naming trends vary across cultures and regions.

  • Is Agify used in academic research?

    Yes. Researchers use Agify to study age-related patterns in datasets — for example, analyzing generational trends in authorship, customer demographics, or population studies. You can find papers referencing Agify.io on Google Scholar . If you use Agify in a paper, we'd love to hear about it.

Use cases & integrations

  • Can the tool be integrated with CRM systems?

    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.

  • Can I use the APIs without writing code?

    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.

Research & ethics

  • What should researchers consider when using name-based prediction in academic studies?

    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.

  • What are the limitations of name-based prediction?

    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.

Pricing & plans

  • Is the API free to use?

    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.

  • What do I get with a paid subscription?

    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.

  • How is usage counted?

    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.

  • What happens if I exceed my plan's limit?

    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.

  • Can I change plans mid-cycle?

    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.

  • Do unused names roll over to next month?

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

  • What's the difference between monthly and yearly billing?

    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.

  • Will my price go up if you change your pricing?

    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.

  • Can I cancel anytime?

    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.

Payments & billing

  • What payment methods do you accept?

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

  • Is my payment information safe?

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

  • How can I update my billing information or payment method?

    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.

  • My card was declined. Will you retry the charge?

    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.

Getting started & API usage

  • How do I get an API key?

    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.

  • Is there any rate limiting?

    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.

  • What kind of customer support do you offer?

    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.

Privacy & compliance

  • What data do you store about my API requests?

    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.

  • Is the service GDPR compliant?

    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 .

  • Do you offer a Data Processing Agreement (DPA)?

    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 .

  • Where are your servers located?

    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.