openapi: 3.0.3
info:
  title: TextGears API
  description: >-
    TextGears is a grammar checking and text analysis REST API providing spelling
    corrections, grammar error detection, readability scoring, language detection,
    text summarization, and custom dictionary management across 11 languages.
    The service processes over 10.8 million API requests daily with distributed
    infrastructure across Estonia, Singapore, and the United States.
  version: 1.0.0
  contact:
    url: https://textgears.com
  termsOfService: https://textgears.com/terms
  license:
    name: Commercial
    url: https://textgears.com
servers:
  - url: https://api.textgears.com
    description: Auto-routing (recommended)
  - url: https://eu.api.textgears.com
    description: Europe
  - url: https://us.api.textgears.com
    description: United States
  - url: https://sg.api.textgears.com
    description: Asia (Singapore)
security:
  - apiKeyQuery: []
  - apiKeyHeader: []
tags:
  - name: Grammar
    description: Grammar and spelling error detection and correction
  - name: Readability
    description: Text readability scoring and analysis
  - name: Language
    description: Language detection
  - name: Summarization
    description: Text summarization and keyword extraction
  - name: Account
    description: Account usage and quota management
  - name: Dictionaries
    description: Custom dictionary management
  - name: Exceptions
    description: Custom exception (whitelist) management
paths:
  /grammar:
    post:
      operationId: checkGrammar
      summary: Check grammar
      description: >-
        Identifies spelling, grammar, style, and punctuation errors in the
        provided text with suggested corrections. Supports 11 languages and
        multiple English dialects.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/CheckRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/CheckRequest'
      responses:
        '200':
          description: Grammar check result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GrammarResponse'
              example:
                status: true
                response:
                  errors:
                    - id: e492411846
                      offset: 5
                      length: 2
                      bad: is
                      better:
                        - am
                      type: grammar
                      description: Subject-verb agreement error
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /spelling:
    post:
      operationId: checkSpelling
      summary: Check spelling
      description: >-
        Focuses on widespread spelling mistakes only, offering a lighter-weight
        alternative to full grammar analysis.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/CheckRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/CheckRequest'
      responses:
        '200':
          description: Spelling check result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GrammarResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /correct:
    post:
      operationId: correct
      summary: Auto-correct text
      description: >-
        Returns a corrected version of the input text with grammar and spelling
        errors automatically fixed.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/CheckRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/CheckRequest'
      responses:
        '200':
          description: Auto-corrected text
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CorrectResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /suggest:
    post:
      operationId: suggest
      summary: Get text suggestions
      description: >-
        Returns style and grammar improvement suggestions for the provided text.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/BaseRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/BaseRequest'
      responses:
        '200':
          description: Text suggestions
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GrammarResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /readability:
    post:
      operationId: checkReadability
      summary: Check readability
      description: >-
        Calculates readability metrics using multiple algorithms including
        Flesch-Kincaid, Gunning Fog, Coleman-Liau, and SMOG, plus emotion
        analysis and word counts.
      tags:
        - Readability
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/BaseRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/BaseRequest'
      responses:
        '200':
          description: Readability analysis result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ReadabilityResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /analyze:
    post:
      operationId: analyzeText
      summary: Analyze text
      description: >-
        Combines grammar checking with readability metrics and text statistics in
        a single request.
      tags:
        - Readability
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/CheckRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/CheckRequest'
      responses:
        '200':
          description: Combined text analysis result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AnalyzeResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /detect:
    post:
      operationId: detectLanguage
      summary: Detect language
      description: >-
        Determines the language and dialect of the provided text with
        probability scores for multiple language candidates.
      tags:
        - Language
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/DetectRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/DetectRequest'
      responses:
        '200':
          description: Language detection result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DetectResponse'
              example:
                status: true
                response:
                  language: en-US
                  multiLanguages:
                    - language: en-US
                      score: 0.95
                    - language: en-GB
                      score: 0.05
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /summarize:
    post:
      operationId: summarize
      summary: Summarize text
      description: >-
        Extracts key sentences, highlights important passages, and identifies
        ranked keywords from longer texts.
      tags:
        - Summarization
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/BaseRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/BaseRequest'
      responses:
        '200':
          description: Text summarization result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SummarizeResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /paraphrase:
    post:
      operationId: paraphrase
      summary: Paraphrase text
      description: >-
        Returns a paraphrased version of the provided text. Supports creativity
        level configuration.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/TransformRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/TransformRequest'
      responses:
        '200':
          description: Paraphrased text
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TransformResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /translate:
    post:
      operationId: translate
      summary: Translate text
      description: Translates the provided text to a specified target language.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/TranslateRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/TranslateRequest'
      responses:
        '200':
          description: Translated text
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TransformResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /split:
    post:
      operationId: splitSentences
      summary: Split text into sentences
      description: Splits the provided text into individual sentences.
      tags:
        - Grammar
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/BaseRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/BaseRequest'
      responses:
        '200':
          description: Split sentences result
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SplitResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /account/resourcequota:
    get:
      operationId: getAccountResourceQuota
      summary: Get account resource quota
      description: Returns the current API quota limits for the authenticated account.
      tags:
        - Account
      responses:
        '200':
          description: Account resource quota
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/QuotaResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /account/usage:
    get:
      operationId: getAccountUsage
      summary: Get account usage statistics
      description: Returns API usage statistics for the authenticated account within a date range.
      tags:
        - Account
      parameters:
        - name: period_start
          in: query
          description: Start of the usage period (Unix timestamp or ISO date)
          schema:
            type: string
        - name: period_end
          in: query
          description: End of the usage period (Unix timestamp or ISO date)
          schema:
            type: string
      responses:
        '200':
          description: Account usage statistics
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UsageResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/createdictionary:
    post:
      operationId: createDictionary
      summary: Create custom dictionary
      description: Creates a new custom dictionary for storing exceptions and whitelisted terms.
      tags:
        - Dictionaries
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/DictionaryRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/DictionaryRequest'
      responses:
        '200':
          description: Created dictionary details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DictionaryResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/updatedictionary:
    post:
      operationId: updateDictionary
      summary: Update custom dictionary
      description: Updates the title or properties of an existing custom dictionary.
      tags:
        - Dictionaries
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/DictionaryRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/DictionaryRequest'
      responses:
        '200':
          description: Updated dictionary details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DictionaryResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/listdictionaries:
    get:
      operationId: listDictionaries
      summary: List custom dictionaries
      description: Returns a paginated list of all custom dictionaries for the account.
      tags:
        - Dictionaries
      parameters:
        - name: limit
          in: query
          required: true
          description: Maximum number of dictionaries to return
          schema:
            type: integer
            minimum: 1
            maximum: 100
        - name: offset
          in: query
          description: Number of dictionaries to skip (for pagination)
          schema:
            type: integer
            minimum: 0
            default: 0
      responses:
        '200':
          description: List of dictionaries
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DictionaryListResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/deletedictionary:
    post:
      operationId: deleteDictionary
      summary: Delete custom dictionary
      description: Permanently deletes a custom dictionary and all its exceptions.
      tags:
        - Dictionaries
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
                - id
              properties:
                id:
                  type: string
                  description: Custom dictionary identifier
          application/json:
            schema:
              type: object
              required:
                - id
              properties:
                id:
                  type: string
                  description: Custom dictionary identifier
      responses:
        '200':
          description: Deletion confirmation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SuccessResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/addexception:
    post:
      operationId: addException
      summary: Add dictionary exception
      description: Adds a word or phrase exception to a custom dictionary.
      tags:
        - Exceptions
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/ExceptionRequest'
          application/json:
            schema:
              $ref: '#/components/schemas/ExceptionRequest'
      responses:
        '200':
          description: Created exception details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ExceptionResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/listexceptions:
    get:
      operationId: listExceptions
      summary: List dictionary exceptions
      description: Returns a paginated list of exceptions for a custom dictionary.
      tags:
        - Exceptions
      parameters:
        - name: limit
          in: query
          required: true
          description: Maximum number of exceptions to return
          schema:
            type: integer
            minimum: 1
            maximum: 100
        - name: offset
          in: query
          description: Number of exceptions to skip (for pagination)
          schema:
            type: integer
            minimum: 0
            default: 0
        - name: dictionary_id
          in: query
          description: Filter exceptions by dictionary ID
          schema:
            type: string
        - name: text
          in: query
          description: Filter exceptions by text content
          schema:
            type: string
        - name: type
          in: query
          description: Filter exceptions by type (1=word, 2=phrase)
          schema:
            type: integer
            enum: [1, 2]
        - name: lang
          in: query
          description: Filter exceptions by language code
          schema:
            type: string
      responses:
        '200':
          description: List of exceptions
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ExceptionListResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
  /custom/deleteexception:
    post:
      operationId: deleteException
      summary: Delete dictionary exception
      description: Removes an exception from a custom dictionary.
      tags:
        - Exceptions
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
                - id
              properties:
                id:
                  type: string
                  description: Exception identifier
                dictionary_id:
                  type: string
                  description: Dictionary identifier containing the exception
          application/json:
            schema:
              type: object
              required:
                - id
              properties:
                id:
                  type: string
                  description: Exception identifier
                dictionary_id:
                  type: string
                  description: Dictionary identifier containing the exception
      responses:
        '200':
          description: Deletion confirmation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SuccessResponse'
        '400':
          $ref: '#/components/responses/ErrorResponse'
components:
  securitySchemes:
    apiKeyQuery:
      type: apiKey
      in: query
      name: key
      description: API key passed as a query parameter
    apiKeyHeader:
      type: http
      scheme: basic
      description: API key passed as HTTP Basic Authorization header value
  schemas:
    BaseRequest:
      type: object
      required:
        - text
      properties:
        text:
          type: string
          description: UTF-8 encoded text to analyze
        language:
          type: string
          description: Language code (BCP 47 format)
          default: en-US
          example: en-US
          enum:
            - en-US
            - en-GB
            - en-ZA
            - en-AU
            - en-NZ
            - fr-FR
            - de-DE
            - de-AT
            - de-CH
            - pt-PT
            - pt-BR
            - it-IT
            - ar-AR
            - ru-RU
            - es-ES
            - ja-JP
            - zh-CN
            - el-GR
        key:
          type: string
          description: API authentication key (if not provided via header or query param)
        ai:
          type: boolean
          description: Enable AI-enhanced analysis
          default: false
        whitelist:
          type: array
          items:
            type: string
          description: Words or phrases to exclude from error detection
        dictionary_id:
          type: string
          description: Custom dictionary identifier to use for exception lookup
    CheckRequest:
      allOf:
        - $ref: '#/components/schemas/BaseRequest'
        - type: object
          properties:
            rules:
              type: array
              items:
                type: string
              description: Specific grammar rules to apply or exclude
    DetectRequest:
      type: object
      required:
        - text
      properties:
        text:
          type: string
          description: UTF-8 encoded text for language detection
        key:
          type: string
          description: API authentication key
    TransformRequest:
      allOf:
        - $ref: '#/components/schemas/CheckRequest'
        - type: object
          properties:
            creativity:
              type: number
              description: Creativity level for paraphrasing (0.0 to 1.0)
              minimum: 0
              maximum: 1
    TranslateRequest:
      allOf:
        - $ref: '#/components/schemas/TransformRequest'
        - type: object
          required:
            - target_language
          properties:
            target_language:
              type: string
              description: Target language code for translation
              example: fr-FR
    DictionaryRequest:
      type: object
      properties:
        id:
          type: string
          description: Custom dictionary identifier
        title:
          type: string
          description: Human-readable dictionary title
    ExceptionRequest:
      type: object
      required:
        - text
        - type
        - lang
      properties:
        text:
          type: string
          description: Word or phrase to add as exception
        type:
          type: integer
          description: Exception type (1=word, 2=phrase)
          enum: [1, 2]
        lang:
          type: string
          description: Language code for the exception
        dictionary_id:
          type: string
          description: Dictionary to add the exception to
        description:
          type: string
          description: Optional description of the exception
        suggestions:
          type: array
          items:
            type: string
          description: Alternative suggestions to offer instead of this exception
    GrammarError:
      type: object
      properties:
        id:
          type: string
          description: Unique error identifier
        offset:
          type: integer
          description: Character offset of the error in the original text
        length:
          type: integer
          description: Length of the error span in characters
        bad:
          type: string
          description: The erroneous text
        better:
          type: array
          items:
            type: string
          description: Suggested corrections
        type:
          type: string
          description: Error type classification
          enum:
            - grammar
            - spelling
            - punctuation
            - style
        description:
          type: string
          description: Human-readable error description
    GrammarResponse:
      type: object
      properties:
        status:
          type: boolean
          description: Whether the request was successful
        response:
          type: object
          properties:
            errors:
              type: array
              items:
                $ref: '#/components/schemas/GrammarError'
    CorrectResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            corrected:
              type: string
              description: The auto-corrected text
    ReadabilityResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            stats:
              type: object
              description: Text statistics
              properties:
                fleschKincaid:
                  type: object
                  properties:
                    readingEase:
                      type: number
                    grade:
                      type: number
                gunningFog:
                  type: number
                colemanLiau:
                  type: number
                smog:
                  type: number
                wordCount:
                  type: integer
                sentenceCount:
                  type: integer
                characterCount:
                  type: integer
            emotion:
              type: object
              description: Emotion analysis results
    AnalyzeResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            errors:
              type: array
              items:
                $ref: '#/components/schemas/GrammarError'
            stats:
              type: object
              description: Text statistics and readability metrics
    DetectResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            language:
              type: string
              description: Most likely language code detected
            multiLanguages:
              type: array
              items:
                type: object
                properties:
                  language:
                    type: string
                  score:
                    type: number
                    description: Probability score (0.0 to 1.0)
    SummarizeResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            keywords:
              type: array
              items:
                type: object
                properties:
                  key:
                    type: string
                  count:
                    type: integer
                  score:
                    type: number
            highlight:
              type: array
              items:
                type: string
              description: Key highlighted sentences
            sentences:
              type: array
              items:
                type: string
    TransformResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            result:
              type: string
              description: Transformed text output
    SplitResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            sentences:
              type: array
              items:
                type: string
    QuotaResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            limit:
              type: integer
              description: Total request limit
            used:
              type: integer
              description: Requests used
            remaining:
              type: integer
              description: Remaining requests
    UsageResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: array
          items:
            type: object
            properties:
              date:
                type: string
                format: date
              requests:
                type: integer
    DictionaryResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            id:
              type: string
              description: Dictionary identifier
            title:
              type: string
              description: Dictionary title
    DictionaryListResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            items:
              type: array
              items:
                $ref: '#/components/schemas/DictionaryResponse/properties/response'
            total:
              type: integer
    ExceptionResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            id:
              type: string
            text:
              type: string
            type:
              type: integer
            lang:
              type: string
            dictionary_id:
              type: string
    ExceptionListResponse:
      type: object
      properties:
        status:
          type: boolean
        response:
          type: object
          properties:
            items:
              type: array
              items:
                $ref: '#/components/schemas/ExceptionResponse/properties/response'
            total:
              type: integer
    SuccessResponse:
      type: object
      properties:
        status:
          type: boolean
          example: true
        response:
          type: object
    ErrorResponse:
      type: object
      properties:
        status:
          type: boolean
          example: false
        error_code:
          type: integer
          description: Error code
          enum: [500, 501, 600, 606, 607]
        description:
          type: string
          description: Human-readable error description
  responses:
    ErrorResponse:
      description: API error
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          examples:
            invalidKey:
              summary: Invalid API key
              value:
                status: false
                error_code: 600
                description: Invalid key
            rateLimitExceeded:
              summary: Rate limit exceeded
              value:
                status: false
                error_code: 607
                description: Request limit exceeded