M
API Matrix

Lingua Robot API

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

Lingua Robot is a dictionary API that provides word definitions, pronunciations, synonyms, antonyms, and related forms for English words via a clean JSON REST interface. It requires an API key obtained by registering for a free tier account. The free plan includes a limited number of requests per day, making it accessible for small projects and learning.

💡

Beginner Tip

The /lemmas endpoint is the best starting point — it returns definitions, pronunciations, and word forms all in one response for a given word. Keep your API key in an environment variable rather than hardcoding it in your source code.

Available Data

word definitions
pronunciation
synonyms and antonyms
example sentences
part of speech

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

lemma The base dictionary form of the queried word.
definitions List of definition objects grouped by part of speech.
pronunciations Phonetic transcriptions (IPA) and optional audio URLs for the word.
synonyms List of synonymous words or phrases.
antonyms List of words with opposite meanings.

Implementation Example 

const url = "https://www.linguarobot.io/";
// 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 Authorization header format is incorrect or the API key is invalid.
✓ Use the format "Authorization: Token YOUR_API_KEY" — make sure to include the word Token before the key.
404 Not Found for a word The word is not in the Lingua Robot lexical database.
✓ Try the base lemma form of the word (e.g., "run" instead of "running") or check for spelling errors.
429 Too Many Requests You have exceeded the daily request limit on the free tier.
✓ Implement request caching for repeated lookups or upgrade to a paid plan for higher limits.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 5/20
🔒 Security 15/15
🛠 Developer XP 17/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

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

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