SLNG

SLNG Deepgram Nova 3 API

Deepgram Nova 3 with VAD and speaker diarization.

GitHub OpenAPI

Operations 4

POST /v1/stt/slng/deepgram/nova:3-en Nova 3 (English) #
POST /v1/stt/slng/deepgram/nova:3-es Nova 3 (Spanish) #
POST /v1/stt/slng/deepgram/nova:3-hi Nova 3 (Hindi) #
POST /v1/stt/slng/deepgram/nova:3-multi Nova 3 (Multi-Language) #

Specifications

⚙
OpenAPI
https://artifacts.apis.io/slng/openapi/slng-deepgram-nova-3-api-openapi.yml
⚙
AsyncAPI
https://artifacts.apis.io/slng/asyncapi/slng-slng-asyncapi.yml
⚙
AsyncAPI
https://artifacts.apis.io/slng/asyncapi/slng-stt-slng-asyncapi.yml
⚙
AsyncAPI
https://artifacts.apis.io/slng/asyncapi/slng-tts-slng-asyncapi.yml

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OpenAPI Specification

slng-deepgram-nova-3-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: SLNG Gateway API - SLNG STT Deepgram Nova 3 API
  version: 0.1.0
  description: Unified API for speech-to-text and text-to-speech services.
  contact:
    name: SLNG Support
    email: support@slng.ai
servers:
- url: https://api.slng.ai
  description: Production
- url: https://stageapi.slng.ai
  description: Staging
security:
- BearerAuth: []
tags:
- name: Deepgram Nova 3
  description: Deepgram Nova 3 with VAD and speaker diarization.
paths:
  /v1/stt/slng/deepgram/nova:3-en:
    post:
      operationId: slng/deepgram/nova:3-en
      summary: Nova 3 (English)
      description: Transcribe English audio using SLNG-hosted Deepgram Nova 3.
      tags:
      - Deepgram Nova 3
      parameters:
      - $ref: '#/components/parameters/XRegionSlngNovaEn'
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3EnRequest'
            examples:
              binary:
                summary: Binary audio upload
                value:
                  audio: <binary>
                  language: en
          application/json:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3EnRequest'
            examples:
              url:
                summary: URL-based transcription
                value:
                  url: https://docs.slng.ai/audio/hello.wav
                  language: en
      responses:
        '200':
          $ref: '#/components/responses/SlngDeepgramSttSuccess'
        '400':
          $ref: '#/components/responses/ProviderBadRequest'
        '401':
          $ref: '#/components/responses/ProviderUnauthorized'
        '413':
          $ref: '#/components/responses/ProviderPayloadTooLarge'
        '500':
          $ref: '#/components/responses/ProviderInternalServerError'
        '503':
          $ref: '#/components/responses/ProviderServiceUnavailable'
  /v1/stt/slng/deepgram/nova:3-es:
    post:
      operationId: slng/deepgram/nova:3-es
      summary: Nova 3 (Spanish)
      description: Transcribe Spanish audio using SLNG-hosted Deepgram Nova 3.
      tags:
      - Deepgram Nova 3
      parameters:
      - $ref: '#/components/parameters/XRegionSlngNovaEs'
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3EsRequest'
            examples:
              binary:
                summary: Binary audio upload
                value:
                  audio: <binary>
                  language: es
          application/json:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3EsRequest'
            examples:
              url:
                summary: URL-based transcription
                value:
                  url: https://docs.slng.ai/audio/hello-es.wav
                  language: es
      responses:
        '200':
          $ref: '#/components/responses/SlngDeepgramSttSuccess'
        '400':
          $ref: '#/components/responses/ProviderBadRequest'
        '401':
          $ref: '#/components/responses/ProviderUnauthorized'
        '413':
          $ref: '#/components/responses/ProviderPayloadTooLarge'
        '500':
          $ref: '#/components/responses/ProviderInternalServerError'
        '503':
          $ref: '#/components/responses/ProviderServiceUnavailable'
  /v1/stt/slng/deepgram/nova:3-hi:
    post:
      operationId: slng/deepgram/nova:3-hi
      summary: Nova 3 (Hindi)
      description: Transcribe Hindi audio using SLNG-hosted Deepgram Nova 3.
      tags:
      - Deepgram Nova 3
      parameters:
      - $ref: '#/components/parameters/XRegionSlngNovaHi'
      - $ref: '#/components/parameters/XWorldPartSlngNovaHi'
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3HiRequest'
            examples:
              binary:
                summary: Binary audio upload
                value:
                  audio: <binary>
                  language: hi
          application/json:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3HiRequest'
            examples:
              url:
                summary: URL-based transcription
                value:
                  url: https://docs.slng.ai/audio/hello-hi.wav
                  language: hi
      responses:
        '200':
          $ref: '#/components/responses/SlngDeepgramSttSuccess'
        '400':
          $ref: '#/components/responses/ProviderBadRequest'
        '401':
          $ref: '#/components/responses/ProviderUnauthorized'
        '413':
          $ref: '#/components/responses/ProviderPayloadTooLarge'
        '500':
          $ref: '#/components/responses/ProviderInternalServerError'
        '503':
          $ref: '#/components/responses/ProviderServiceUnavailable'
  /v1/stt/slng/deepgram/nova:3-multi:
    post:
      operationId: slng/deepgram/nova:3-multi
      summary: Nova 3 (Multi-Language)
      description: Transcribe multi-language audio using SLNG-hosted Deepgram Nova 3.
      tags:
      - Deepgram Nova 3
      parameters:
      - $ref: '#/components/parameters/XRegionSlngNovaMulti'
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3MultiRequest'
            examples:
              binary:
                summary: Binary audio upload
                value:
                  audio: <binary>
                  language: multi
          application/json:
            schema:
              $ref: '#/components/schemas/SlngDeepgramNova3MultiRequest'
            examples:
              url:
                summary: URL-based transcription
                value:
                  url: https://docs.slng.ai/audio/hello.wav
                  language: multi
      responses:
        '200':
          $ref: '#/components/responses/SlngDeepgramSttSuccess'
        '400':
          $ref: '#/components/responses/ProviderBadRequest'
        '401':
          $ref: '#/components/responses/ProviderUnauthorized'
        '413':
          $ref: '#/components/responses/ProviderPayloadTooLarge'
        '500':
          $ref: '#/components/responses/ProviderInternalServerError'
        '503':
          $ref: '#/components/responses/ProviderServiceUnavailable'
components:
  schemas:
    DeepgramSttResponse:
      type: object
      description: 3rd Party Deepgram API response format.
      required:
      - results
      properties:
        results:
          type: object
          properties:
            channels:
              type: array
              items:
                type: object
                properties:
                  alternatives:
                    type: array
                    items:
                      type: object
                      properties:
                        transcript:
                          type: string
                        confidence:
                          type: number
                  detected_language:
                    type: string
        metadata:
          type: object
          properties:
            request_id:
              type: string
            model:
              type: string
    SttAudioRequestBase:
      type: object
      properties:
        audio:
          type: string
          format: binary
          description: Audio file (multipart) or base64-encoded audio (JSON).
        url:
          type: string
          description: Publicly accessible audio URL.
          example: https://docs.slng.ai/audio/hello.wav
    SlngDeepgramNova3EnRequest:
      allOf:
      - $ref: '#/components/schemas/SttAudioRequestBase'
      - $ref: '#/components/schemas/SlngDeepgramSttOptionsBase'
      - type: object
        properties:
          language:
            $ref: '#/components/schemas/SlngDeepgramNova3EnLanguage'
    SlngDeepgramNova3EsLanguage:
      type: string
      description: Supported Spanish language code.
      example: es
      enum:
      - es
      - es-us
      - es-419
      - es-ar
      - es-mx
      - es-es
    SlngDeepgramNova3MultiLanguage:
      type: string
      description: Supported language code. Nova 3 Multi auto-detects language; only `multi` is accepted.
      example: multi
      default: multi
      enum:
      - multi
    SlngDeepgramSttOptionsBase:
      type: object
      description: SLNG-hosted Deepgram STT processing options.
      properties:
        model:
          type: string
          description: Model name override.
          default: nova-3
        enable_partials:
          type: boolean
          description: Enable partial/interim transcription results for streaming.
          default: true
        punctuate:
          type: boolean
          description: Add punctuation and capitalization.
          default: false
        smart_format:
          type: boolean
          description: Apply formatting to improve readability (dates, times, numbers, etc.).
          default: false
        utterances:
          type: boolean
          description: Segment transcript into utterances.
          default: false
        paragraphs:
          type: boolean
          description: Add paragraph formatting.
          default: false
        numerals:
          type: boolean
          description: Convert spoken numbers to digits.
          default: false
        profanity_filter:
          type: boolean
          description: Filter profanity from transcript.
          default: false
        redact:
          type: array
          description: Redact sensitive information (pci, ssn, numbers).
          items:
            type: string
            enum:
            - pci
            - ssn
            - numbers
        detect_language:
          type: boolean
          description: Auto-detect spoken language.
          default: false
        filler_words:
          type: boolean
          description: Include filler words (uh, um) in transcript.
          default: false
        multichannel:
          type: boolean
          description: Enable multi-channel audio processing.
          default: false
        keywords:
          type: array
          description: Keywords to boost recognition accuracy.
          items:
            type: string
        encoding:
          type: string
          description: Input audio encoding.
          default: linear16
          enum:
          - linear16
          - flac
          - mulaw
          - amr-nb
          - amr-wb
          - opus
          - speex
          - mp3
          - mp4
          - webm
          - aac
          - ogg
        sample_rate:
          type: integer
          description: Input audio sample rate in Hz.
          default: 16000
        channels:
          type: integer
          description: Number of audio channels.
          minimum: 1
        endpointing:
          oneOf:
          - type: integer
            minimum: 0
          - type: boolean
          default: 10
          description: Time in milliseconds of silence before finalizing speech. Enabled by default at 10ms on Deepgram's side. Set to false to disable endpointing entirely.
        utterance_end_ms:
          type: integer
          minimum: 200
          maximum: 5000
          default: 1000
          description: Time in milliseconds of silence between words before sending an UtteranceEnd message. Default is 1000ms, minimum 200ms, maximum 5000ms. Requires interim_results (enable_partials) to be true.
        tag:
          type: string
          description: Tag for request tracking.
    SlngDeepgramNova3MultiRequest:
      allOf:
      - $ref: '#/components/schemas/SttAudioRequestBase'
      - $ref: '#/components/schemas/SlngDeepgramSttOptionsBase'
      - type: object
        properties:
          language:
            $ref: '#/components/schemas/SlngDeepgramNova3MultiLanguage'
    SlngDeepgramNova3EsRequest:
      allOf:
      - $ref: '#/components/schemas/SttAudioRequestBase'
      - $ref: '#/components/schemas/SlngDeepgramSttOptionsBase'
      - type: object
        properties:
          language:
            $ref: '#/components/schemas/SlngDeepgramNova3EsLanguage'
    SlngDeepgramNova3HiRequest:
      allOf:
      - $ref: '#/components/schemas/SttAudioRequestBase'
      - $ref: '#/components/schemas/SlngDeepgramSttOptionsBase'
      - type: object
        properties:
          language:
            $ref: '#/components/schemas/SlngDeepgramNova3HiLanguage'
    SlngDeepgramNova3HiLanguage:
      type: string
      description: Supported language codes for the Hindi variant.
      example: hi
      enum:
      - hi
      - en
    ProviderErrorResponse:
      type: object
      description: 'Provider error response. Contains error information from the upstream provider.

        Common errors include invalid speakers, unsupported languages, or malformed requests.

        '
      properties:
        error:
          type: string
          description: Error type or category (e.g., "TTS service error", "Validation error").
          example: TTS service error
        status:
          type: number
          description: Original HTTP status code from the provider (may differ from gateway response code).
          example: 400
        details:
          type: string
          description: 'Detailed error message from the provider. For TTS errors, this typically includes

            the specific validation failure (e.g., invalid speaker ID for the selected model/language).

            '
          example: 'Rime TTS API error: 400 Bad Request - Invalid argument: Invalid speaker: aurelie'
      required:
      - error
    SlngDeepgramNova3EnLanguage:
      type: string
      description: Supported English language code.
      example: en
      enum:
      - en
      - en-au
      - en-us
      - en-nz
      - en-gb
      - en-in
  parameters:
    XWorldPartSlngNovaHi:
      name: X-World-Part-Override
      in: header
      required: false
      description: Target world part override. Auto-selected if not provided.
      schema:
        type: string
        enum:
        - ap
    XRegionSlngNovaEs:
      name: X-Region-Override
      in: header
      required: false
      description: Target region override. Auto-selected if not provided.
      schema:
        type: string
        enum:
        - us-east-1
    XRegionSlngNovaHi:
      name: X-Region-Override
      in: header
      required: false
      description: Target region override. Auto-selected if not provided.
      schema:
        type: string
        enum:
        - asia-south1
    XRegionSlngNovaEn:
      name: X-Region-Override
      in: header
      required: false
      description: Target region override. Auto-selected if not provided.
      schema:
        type: string
        enum:
        - asia-south1
        - australia-southeast1
        - us-east-1
    XRegionSlngNovaMulti:
      name: X-Region-Override
      in: header
      required: false
      description: Target region override. Auto-selected if not provided.
      schema:
        type: string
        enum:
        - eu-north-1
  responses:
    SlngDeepgramSttSuccess:
      description: Transcription successful.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/DeepgramSttResponse'
          examples:
            basic:
              summary: Basic transcription
              value:
                results:
                  channels:
                  - alternatives:
                    - transcript: hello from sunny barcelona
                      confidence: 0.98
                metadata:
                  request_id: req-123
                  model: nova-3
    ProviderInternalServerError:
      description: Internal server error from the provider.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ProviderErrorResponse'
          examples:
            processing-error:
              summary: Processing error
              value:
                error: Service error
                details: Internal processing error
    ProviderPayloadTooLarge:
      description: Audio file exceeds size limit.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ProviderErrorResponse'
    ProviderBadRequest:
      description: Bad request - invalid parameters provided.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ProviderErrorResponse'
          examples:
            validation-error:
              summary: Validation error
              value:
                error: Validation error
                details: 'Missing required field: text'
    ProviderServiceUnavailable:
      description: Service unavailable.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ProviderErrorResponse'
    ProviderUnauthorized:
      description: Invalid or missing API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ProviderErrorResponse'
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: 'API key issued by SLNG. Pass as `Authorization: Bearer <token>`.

        '