# Language Code Lookup by ISO 639 or BCP 47

> Language Code Lookup by ISO 639 or BCP 47 is a paid API for AI agents from country-codes-iso.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Look up a language by ISO 639-1, ISO 639-2 (B or T), or BCP 47 tag and return all code forms and names.

## Facts

- Endpoint: GET https://country-codes-iso.x402tookit.com/language-lookup?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/language-code-lookup-by-iso-639-or-bcp-47-66bf6ef5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XC0udmOvcMd5LlAkSWyt6

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability language-code-lookup-by-iso-639-or-bcp-47-66bf6ef5
```

Example prompt: What are all the ISO 639-1 and 639-2 codes for Welsh — I have the English name but need both the bibliographic and terminological forms.

## When to prefer this

Use this endpoint when you have any form of ISO 639-1, ISO 639-2 (B or T), BCP 47 tag, or English language name and need to resolve the full set of standardized code equivalents. Prefer this over the generic multi-entity lookup when your query is specifically a language identifier. It is ideal for internationalization pipelines, localization config validation, or data normalization tasks where language codes need to be cross-referenced.

## Known failure modes

- Unknown or unsupported language input returns an empty or null language object
- Ambiguous BCP 47 subtags (e.g. regional variants not in ISO 639) may not resolve
- Misspelled English language names may not match
- Missing required query parameter 'q' returns a 400-level error
- ISO 639-3 codes (three-letter codes for smaller languages) are not supported — only 639-1 and 639-2

## How this service works

Look up a language by ISO 639-1, 639-2 (B or T) code, BCP 47 tag or English name; returns all code forms.

## Output

Returns a language object containing ISO 639-1 code, ISO 639-2 B (bibliographic) code, ISO 639-2 T (terminological) code, and an array of known English names for the language, along with which query field was matched and metadata like source and disclaimer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "q"
     ],
     "properties": {
      "q": {
       "type": "string",
       "description": "Language code, tag or name: fr, fra, fre, pt-BR, Welsh"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "language": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "names": {
         "type": [
          "array",
          "null"
         ],
         "items": {
          "type": "string"
         }
        },
        "iso639_1": {
         "type": [
          "null",
          "string"
         ]
        },
        "iso639_2": {
         "type": [
          "null",
          "string"
         ]
        },
        "iso639_2T": {
         "type": [
          "null",
          "string"
         ]
        }
       }
      },
      "matchedOn": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "attribution": {
       "type": [
        "null",
        "string"
       ]
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/language-code-lookup-by-iso-639-or-bcp-47-66bf6ef5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from country-codes-iso.x402tookit.com](https://www.zero.xyz/host/country-codes-iso.x402tookit.com/llms.txt)