openapi: 3.0.3
info:
  title: languagelayer API
  description: >
    Language detection REST API that identifies 173 languages and accents from
    text with confidence scores, character usage statistics, and batch processing
    support, powered by an AI-based detection algorithm via the APILayer platform.
  version: '1.0'
  contact:
    name: APILayer Support
    email: support@apilayer.net
    url: https://languagelayer.com/
  termsOfService: https://languagelayer.com/terms
externalDocs:
  description: Official Documentation
  url: https://languagelayer.com/documentation
servers:
  - url: https://apilayer.net/api
    description: Production API server
security:
  - accessKey: []
paths:
  /detect:
    get:
      operationId: detectLanguage
      summary: Detect Language
      description: >
        Identifies the language of a single text string, returning language code,
        language name, confidence score, probability score, and character usage
        statistics across 173 supported languages.
      parameters:
        - name: access_key
          in: query
          required: true
          description: Your API access key obtained from languagelayer.com.
          schema:
            type: string
        - name: query
          in: query
          required: true
          description: The URL-encoded text string whose language you want to detect.
          schema:
            type: string
      responses:
        '200':
          description: Successful language detection response.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DetectResponse'
              example:
                success: true
                results:
                  - language_code: en
                    language_name: English
                    probability: 78.4
                    percentage: 99.2
                    reliable_result: true
        '401':
          description: Unauthorized — missing or invalid access key.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '404':
          description: Endpoint not found.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /batch:
    post:
      operationId: batchDetectLanguage
      summary: Batch Detect Languages
      description: >
        Identifies the language of multiple text strings in a single request,
        returning language detection results for each text supplied.
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
                - access_key
                - query[]
              properties:
                access_key:
                  type: string
                  description: Your API access key obtained from languagelayer.com.
                'query[]':
                  type: array
                  items:
                    type: string
                  description: Array of text strings to detect languages for.
      responses:
        '200':
          description: Successful batch language detection response.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/BatchResponse'
              example:
                success: true
                results:
                  - - language_code: en
                      language_name: English
                      probability: 78.4
                      percentage: 99.2
                      reliable_result: true
                  - - language_code: fr
                      language_name: French
                      probability: 81.2
                      percentage: 97.5
                      reliable_result: true
        '401':
          description: Unauthorized — missing or invalid access key.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  securitySchemes:
    accessKey:
      type: apiKey
      in: query
      name: access_key
      description: API access key obtained from languagelayer.com.
  schemas:
    LanguageResult:
      type: object
      description: Language detection result for a single text.
      properties:
        language_code:
          type: string
          description: ISO 639-1 or ISO 639-2 language code (e.g. "en", "fr").
          example: en
        language_name:
          type: string
          description: Human-readable language name (e.g. "English").
          example: English
        probability:
          type: number
          format: float
          description: >
            Probability score indicating how strongly the language was matched,
            based on cross-referencing words, expressions, and grammatical
            constructions.
          example: 78.4
        percentage:
          type: number
          format: float
          description: >
            Confidence percentage indicating the API's level of confidence that
            the detected language is correct.
          example: 99.2
        reliable_result:
          type: boolean
          description: >
            Boolean flag indicating whether the detection result is considered
            reliable.
          example: true
    DetectResponse:
      type: object
      description: Response object for a single text language detection request.
      properties:
        success:
          type: boolean
          description: Whether the API request was successful.
          example: true
        error:
          $ref: '#/components/schemas/ErrorInfo'
        results:
          type: array
          description: >
            List of language detection results ordered by probability score
            (highest first).
          items:
            $ref: '#/components/schemas/LanguageResult'
    BatchResponse:
      type: object
      description: Response object for a batch language detection request.
      properties:
        success:
          type: boolean
          description: Whether the API request was successful.
          example: true
        error:
          $ref: '#/components/schemas/ErrorInfo'
        results:
          type: array
          description: >
            Array of result arrays, one per input text, each containing language
            detection results ordered by probability score.
          items:
            type: array
            items:
              $ref: '#/components/schemas/LanguageResult'
    ErrorResponse:
      type: object
      description: Error response object.
      properties:
        success:
          type: boolean
          example: false
        error:
          $ref: '#/components/schemas/ErrorInfo'
    ErrorInfo:
      type: object
      description: Details about an API error.
      properties:
        code:
          type: integer
          description: Numeric error code.
          example: 101
        type:
          type: string
          description: Short error type identifier.
          example: missing_access_key
        info:
          type: string
          description: Human-readable error description.
          example: You have not supplied an API Access Key.