Genderize.io API

⭐ Beginner's Pick Development / No Auth Required Beginner HTTPS CORS
Free to Use Varies (check documentation)

Overview

Genderize.io predicts the likely gender of a given first name using a statistical model trained on a database of over 100 million names from around the world. It returns the predicted gender along with a probability score and the count of name samples used — giving you a confidence measure for each prediction. The API is free for up to 1,000 names per day without authentication.

💡

Beginner Tip

This is one of the simplest APIs you can call — just pass a name in the URL query string and get back a JSON object. No API key required for the free tier. You can also pass a country_id parameter (ISO 3166-1 alpha-2) to get region-specific predictions, since the same name can lean differently by country.

Available Data

prediction result with confidence score
input name or text
statistical data

Example Response

JSON Response
{
  "name": "michael",
  "prediction": "male",
  "count": 234567,
  "probability": 0.87
}

Field Reference

name The input first name as provided in the query, returned as-is.
gender Predicted gender: "male", "female", or null if the name is not in the database.
probability Confidence score from 0.0 to 1.0 — higher means stronger evidence for the predicted gender.
count Number of data samples for this name in the Genderize.io database — larger counts mean more reliable predictions.

Implementation Example

const url = "https://genderize.io/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

probability: 0 or null result The name is not in the Genderize.io database, often due to unusual spelling or a very rare name
Try common alternate spellings or handle the null case gracefully in your code as a name-not-found state.
429 Too Many Requests The free tier limit of 1,000 requests per day has been exceeded
Batch multiple names in a single request using repeated name[] parameters (e.g., ?name[]=alice&name[]=bob) to stay within limits, or subscribe to a paid plan.
Inaccurate prediction for unisex names Names like Alex or Jordan have roughly 50/50 distribution, leading to low probability scores
Check the probability field — if it is below 0.7, treat the prediction as uncertain and avoid acting on it without additional signals.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 15/20
🔒 Security 15/15
🛠 Developer XP 20/20
✓ Reliability 7/15
Response Time 484ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS YES
Category Development
Difficulty Beginner
Verified: 2026-04-04

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