M
API Matrix

Wordnik API

⭐ Beginner's Pick Dictionaries / API Key Intermediate HTTPS
Varies by plan (check documentation)
72 Score
Grade B
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Overview

Wordnik is a comprehensive English dictionary API offering definitions, pronunciations, example sentences, related words, and frequency data sourced from a large corpus of text. A free API key is available after creating a Wordnik account, with a generous request allowance for hobbyist projects. It is well-documented and a popular choice for vocabulary apps and word games.

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Beginner Tip

The /word.json/{word}/definitions endpoint is the best starting point — it returns definitions from multiple sources in a simple array. Store your API key in an environment variable and pass it as the api_key query parameter on every request.

Available Data

word definitions
pronunciation
synonyms and antonyms
example sentences
part of speech
Use case: Integrate dictionary data data into web and mobile applications

Example Response

JSON Response 
{
  "word": "serendipity",
  "phonetic": "/ˌsɛr.ənˈdɪp.ɪ.ti/",
  "meanings": [
    {
      "partOfSpeech": "noun",
      "definition": "The occurrence of events by chance in a happy way"
    }
  ],
  "synonyms": [
    "luck",
    "fortune",
    "chance"
  ]
}

Field Reference

word The word this definition applies to.
text The full definition text.
partOfSpeech Part of speech for this definition (e.g., noun, verb, adjective).
sourceDictionary The dictionary or source from which this definition was taken.
exampleUses Example sentences showing the word used in context.

Implementation Example 

const url = "https://developer.wordnik.com/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "X-API-Key": "YOUR_API_KEY"
  }
});
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

401 Unauthorized The api_key query parameter is missing or the key has not been activated.
✓ Register at wordnik.com, confirm your email to activate the API key, then pass it as api_key in the query string.
Empty definitions array The word is too obscure, misspelled, or not in the Wordnik corpus.
✓ Try using the /word.json/{word}/related endpoint to find alternative or correct forms of the word.
404 Not Found on /word.json/{word} The word in the URL path contains unsupported characters or spaces.
✓ URL-encode the word and ensure it contains only valid characters; compound phrases may need a hyphen instead of a space.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 5/20
🔒 Security 15/15
🛠 Developer XP 12/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth API Key
HTTPS REQUIRED
CORS UNKNOWN
Category Dictionaries
Difficulty Intermediate
Verified: 2026-04-04

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