> ## Documentation Index > Fetch the complete documentation index at: https://docs.slng.ai/llms.txt > Use this file to discover all available pages before exploring further. # Cognigy TTS > Synthesize speech via Cognigy Voice Gateway protocol bridge. ## OpenAPI ````yaml POST /v1/bridges/cognigy/tts/{model_variant} openapi: 3.0.3 info: title: SLNG Gateway API - Cognigy Bridges 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: Cognigy STT Bridge description: Cognigy Voice Gateway STT protocol bridge. - name: Cognigy TTS Bridge description: Cognigy Voice Gateway TTS protocol bridge. paths: /v1/bridges/cognigy/tts/{model_variant}: parameters: - $ref: '#/components/parameters/TtsModelVariantPath' - $ref: '#/components/parameters/RegionQuery' - $ref: '#/components/parameters/WorldPartQuery' post: tags: - Cognigy TTS Bridge summary: Cognigy TTS Bridge description: Synthesize speech via Cognigy Voice Gateway protocol bridge. operationId: cognigy-tts-http requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CognigyTTSRequest' examples: deepgram: summary: Deepgram Aura value: text: Hello, this is a test of text to speech synthesis. model: aura-2-thalia-en orpheus: summary: Orpheus value: prompt: Hello, this is a test of text to speech synthesis. voice: tara responses: '200': $ref: '#/components/responses/TtsSynthesisSuccess' '400': $ref: '#/components/responses/ProviderBadRequest' '403': $ref: '#/components/responses/ForbiddenBearerToken' '500': $ref: '#/components/responses/ProviderInternalServerError' components: parameters: TtsModelVariantPath: name: model_variant in: path required: true description: Target TTS model. Any WebSocket-capable TTS model is supported. schema: type: string enum: - cartesia/sonic:3 - deepgram/aura:2 - elevenlabs/eleven-flash:2 - elevenlabs/eleven-flash:2.5 - elevenlabs/eleven-multilingual:2 - elevenlabs/eleven:3 - gradium/tts:default - kugelaudio/kugel:1 - kugelaudio/kugel:1-turbo - kugelaudio/kugel:2 - kugelaudio/kugel:2-turbo - murf/murftts:falcon - sarvam/bulbul:v3 - slng/canopylabs/orpheus:en - slng/deepgram/aura:2-en - slng/deepgram/aura:2-es - slng/inworld/max:1.5 - slng/rime/arcana:3-en - slng/rime/arcana:3-es - slng/rime/arcana:3-fr - slng/rime/arcana:3-hi - slng/rime/arcana:ar - slng/rime/arcana:de - slng/rime/arcana:en - slng/rime/arcana:es - slng/rime/arcana:fr - slng/rime/coda:0-id - soniox/tts-rt:v1 examples: deepgramAura: summary: Deepgram Aura 2 value: deepgram/aura:2 orpheus: summary: SLNG-hosted Orpheus English value: slng/canopylabs/orpheus:en RegionQuery: name: region in: query required: false description: >- Target region override. Auto-selected if not provided. Equivalent to the `X-Region-Override` header; the header takes precedence when both are set. schema: type: string enum: - ap-southeast-2 - eu-north-1 - us-east-1 WorldPartQuery: name: world-part in: query required: false description: >- Target world part override. Auto-selected if not provided. Equivalent to the `X-World-Part-Override` header; the header takes precedence when both are set. schema: type: string enum: - ap - eu - na schemas: CognigyTTSRequest: type: object description: Cognigy TTS request. properties: text: type: string description: Text to synthesize. prompt: type: string description: Alternative text field for some models. voice: type: string description: Voice identifier. model: type: string description: Model name. language: type: string description: Language code. AudioBinary: type: string format: binary description: Binary audio data. 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 ErrorResponse: type: object description: Standard error response. properties: error: type: string description: Error type or code. message: type: string description: Human-readable error message. statusCode: type: integer description: HTTP status code. required: - error responses: TtsSynthesisSuccess: description: Synthesis successful. content: audio/*: schema: $ref: '#/components/schemas/AudioBinary' 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' ForbiddenBearerToken: description: Missing or invalid Bearer token. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' 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 securitySchemes: BearerAuth: type: http scheme: bearer description: | API key issued by SLNG. Pass as `Authorization: Bearer `. ````