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This guide will help you make your first LangDex API request and explore the linguistic database.

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Prerequisites

  • A LangDex API key (get one at langdex.co/dashboard)
  • A tool to make HTTP requests (curl, Postman, or your preferred language)

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Step 1: Get Your API Key

Sign up or log in to the LangDex Dashboard to create an API key. You’ll need this for all API requests.
Free tier includes 10,000 requests/month. See pricing for higher limits.

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Step 2: Make Your First Request

Let’s start by looking up a language. We’ll query Japanese using its Glottolog code: 
curl -X GET "https://api.langdex.co/v1/languages/nucl1643" \
  -H "Authorization: Bearer YOUR_API_KEY"
Response: 
{
  "id": 1234,
  "glottocode": "nucl1643",
  "iso639_3": "jpn",
  "name": "Japanese",
  "level": "language",
  "family": {
    "glottocode": "japo1237",
    "name": "Japonic"
  },
  "scripts": ["Jpan", "Hira", "Kana", "Latn"],
  "speakers": 125000000
}

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Step 3: Search for Words

Now let’s search for lexemes. We’ll find entries for “water” in Japanese: 
curl -X GET "https://api.langdex.co/v1/lexemes/search?q=water&lang=jpn&limit=5" \
  -H "Authorization: Bearer YOUR_API_KEY"
Response: 
{
  "data": [
    {
      "id": 56789,
      "lemma": "水",
      "reading": "みず",
      "romanization": "mizu",
      "pos": "noun",
      "language": "jpn",
      "senses": [
        {
          "id": 111,
          "gloss": "water (liquid)",
          "meaning_id": 98765
        }
      ],
      "pronunciation": {
        "ipa": "mizɯ"
      }
    }
  ],
  "total": 12,
  "limit": 5,
  "offset": 0
}

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Step 4: Get Translations

Use the meaning ID to find translations across languages: 
curl -X GET "https://api.langdex.co/v1/translations?meaning_id=98765&target_lang=spa,fra,deu" \
  -H "Authorization: Bearer YOUR_API_KEY"
Response: 
{
  "meaning_id": 98765,
  "translations": [
    {
      "language": "spa",
      "lexeme": "agua",
      "pos": "noun",
      "confidence": 0.98
    },
    {
      "language": "fra",
      "lexeme": "eau",
      "pos": "noun",
      "confidence": 0.97
    },
    {
      "language": "deu",
      "lexeme": "Wasser",
      "pos": "noun",
      "confidence": 0.99
    }
  ]
}

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Common Use Cases

Build a Dictionary

Fetch detailed word entries with definitions, pronunciations, and examples

Language Learning App

Access vocabulary with spaced repetition data and proficiency levels

Translation Service

Translate between any language pair via the meaning network

Linguistic Analysis

Query morphological, phonological, and etymological data

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Rate Limits

PlanRequests/monthRate limit
Free10,00010 req/s
Pro100,00050 req/s
EnterpriseUnlimited200 req/s

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Next Steps