--- title: "Create an ephemeral API token for use in client-side applications with the Realtime API. Can be configured with the same session parameters as the `session.update` client event. It responds with a session object, plus a `client_secret` key which contains a usable ephemeral API token that can be used to authenticate browser clients for the Realtime API." url: "https://kongair.terwilligar.com/apis/openai-api-2-3-0/versions/ea92d048-c746-4ead-a6a8-da28d93137d1/operations/create-realtime-session" --- > Full API specification: https://kongair.terwilligar.com/apis/openai-api-2-3-0/versions/ea92d048-c746-4ead-a6a8-da28d93137d1.md # Create an ephemeral API token for use in client-side applications with the Realtime API. Can be configured with the same session parameters as the `session.update` client event. It responds with a session object, plus a `client_secret` key which contains a usable ephemeral API token that can be used to authenticate browser clients for the Realtime API. `POST` `/realtime/sessions` Operation ID: `create-realtime-session` ## Request body (required) Content types: `application/json` ## Responses - `200` - Session created successfully. ## OpenAPI definition ```yaml openapi: 3.0.0 info: title: OpenAI API version: 2.3.0 servers: - url: https://api.openai.com/v1 paths: /realtime/sessions: post: summary: > Create an ephemeral API token for use in client-side applications with the Realtime API. Can be configured with the same session parameters as the `session.update` client event. It responds with a session object, plus a `client_secret` key which contains a usable ephemeral API token that can be used to authenticate browser clients for the Realtime API. operationId: create-realtime-session tags: - Realtime requestBody: description: Create an ephemeral API key with the given session configuration. required: true content: application/json: schema: $ref: "#/components/schemas/RealtimeSessionCreateRequest" responses: "200": description: Session created successfully. content: application/json: schema: $ref: "#/components/schemas/RealtimeSessionCreateResponse" x-oaiMeta: name: Create session group: realtime returns: The created Realtime session object, plus an ephemeral key examples: request: curl: | curl -X POST https://api.openai.com/v1/realtime/sessions \ -H "Authorization: Bearer $OPENAI_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-4o-realtime-preview-2024-12-17", "modalities": ["audio", "text"], "instructions": "You are a friendly assistant." }' response: | { "id": "sess_001", "object": "realtime.session", "model": "gpt-4o-realtime-preview-2024-12-17", "modalities": ["audio", "text"], "instructions": "You are a friendly assistant.", "voice": "alloy", "input_audio_format": "pcm16", "output_audio_format": "pcm16", "input_audio_transcription": { "model": "whisper-1" }, "turn_detection": null, "tools": [], "tool_choice": "none", "temperature": 0.7, "max_response_output_tokens": 200, "client_secret": { "value": "ek_abc123", "expires_at": 1234567890 } } security: - ApiKeyAuth: [] components: schemas: RealtimeSessionCreateRequest: type: object description: Realtime session object configuration. properties: modalities: description: | The set of modalities the model can respond with. To disable audio, set this to ["text"]. items: type: string enum: - text - audio model: type: string description: | The Realtime model used for this session. enum: - gpt-4o-realtime-preview - gpt-4o-realtime-preview-2024-10-01 - gpt-4o-realtime-preview-2024-12-17 - gpt-4o-mini-realtime-preview - gpt-4o-mini-realtime-preview-2024-12-17 instructions: type: string description: > The default system instructions (i.e. system message) prepended to model calls. This field allows the client to guide the model on desired responses. The model can be instructed on response content and format, (e.g. "be extremely succinct", "act friendly", "here are examples of good responses") and on audio behavior (e.g. "talk quickly", "inject emotion into your voice", "laugh frequently"). The instructions are not guaranteed to be followed by the model, but they provide guidance to the model on the desired behavior. Note that the server sets default instructions which will be used if this field is not set and are visible in the `session.created` event at the start of the session. voice: type: string enum: - alloy - ash - ballad - coral - echo - sage - shimmer - verse description: > The voice the model uses to respond. Voice cannot be changed during the session once the model has responded with audio at least once. Current voice options are `alloy`, `ash`, `ballad`, `coral`, `echo` `sage`, `shimmer` and `verse`. input_audio_format: type: string enum: - pcm16 - g711_ulaw - g711_alaw description: > The format of input audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`. For `pcm16`, input audio must be 16-bit PCM at a 24kHz sample rate, single channel (mono), and little-endian byte order. output_audio_format: type: string enum: - pcm16 - g711_ulaw - g711_alaw description: > The format of output audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`. For `pcm16`, output audio is sampled at a rate of 24kHz. input_audio_transcription: type: object description: | Configuration for input audio transcription, defaults to off and can be set to `null` to turn off once on. Input audio transcription is not native to the model, since the model consumes audio directly. Transcription runs asynchronously through [OpenAI Whisper transcription](https://platform.openai.com/docs/api-reference/audio/createTranscription) and should be treated as rough guidance rather than the representation understood by the model. The client can optionally set the language and prompt for transcription, these fields will be passed to the Whisper API. properties: model: type: string description: > The model to use for transcription, `whisper-1` is the only currently supported model. language: type: string description: | The language of the input audio. Supplying the input language in [ISO-639-1](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) (e.g. `en`) format will improve accuracy and latency. prompt: type: string description: > An optional text to guide the model's style or continue a previous audio segment. The [prompt](/docs/guides/speech-to-text#prompting) should match the audio language. turn_detection: type: object description: > Configuration for turn detection. Can be set to `null` to turn off. Server VAD means that the model will detect the start and end of speech based on audio volume and respond at the end of user speech. properties: type: type: string description: > Type of turn detection, only `server_vad` is currently supported. threshold: type: number description: > Activation threshold for VAD (0.0 to 1.0), this defaults to 0.5. A higher threshold will require louder audio to activate the model, and thus might perform better in noisy environments. prefix_padding_ms: type: integer description: | Amount of audio to include before the VAD detected speech (in milliseconds). Defaults to 300ms. silence_duration_ms: type: integer description: > Duration of silence to detect speech stop (in milliseconds). Defaults to 500ms. With shorter values the model will respond more quickly, but may jump in on short pauses from the user. create_response: type: boolean default: true description: | Whether or not to automatically generate a response when VAD is enabled. `true` by default. tools: type: array description: Tools (functions) available to the model. items: type: object properties: type: type: string enum: - function description: The type of the tool, i.e. `function`. x-stainless-const: true name: type: string description: The name of the function. description: type: string description: > The description of the function, including guidance on when and how to call it, and guidance about what to tell the user when calling (if anything). parameters: type: object description: Parameters of the function in JSON Schema. tool_choice: type: string description: > How the model chooses tools. Options are `auto`, `none`, `required`, or specify a function. temperature: type: number description: > Sampling temperature for the model, limited to [0.6, 1.2]. Defaults to 0.8. max_response_output_tokens: oneOf: - type: integer - type: string enum: - inf x-stainless-const: true description: | Maximum number of output tokens for a single assistant response, inclusive of tool calls. Provide an integer between 1 and 4096 to limit output tokens, or `inf` for the maximum available tokens for a given model. Defaults to `inf`. RealtimeSessionCreateResponse: type: object description: > A new Realtime session configuration, with an ephermeral key. Default TTL for keys is one minute. properties: client_secret: type: object description: Ephemeral key returned by the API. properties: value: type: string description: > Ephemeral key usable in client environments to authenticate connections to the Realtime API. Use this in client-side environments rather than a standard API token, which should only be used server-side. expires_at: type: integer description: > Timestamp for when the token expires. Currently, all tokens expire after one minute. required: - value - expires_at modalities: description: | The set of modalities the model can respond with. To disable audio, set this to ["text"]. items: type: string enum: - text - audio instructions: type: string description: > The default system instructions (i.e. system message) prepended to model calls. This field allows the client to guide the model on desired responses. The model can be instructed on response content and format, (e.g. "be extremely succinct", "act friendly", "here are examples of good responses") and on audio behavior (e.g. "talk quickly", "inject emotion into your voice", "laugh frequently"). The instructions are not guaranteed to be followed by the model, but they provide guidance to the model on the desired behavior. Note that the server sets default instructions which will be used if this field is not set and are visible in the `session.created` event at the start of the session. voice: type: string enum: - alloy - ash - ballad - coral - echo - sage - shimmer - verse description: > The voice the model uses to respond. Voice cannot be changed during the session once the model has responded with audio at least once. Current voice options are `alloy`, `ash`, `ballad`, `coral`, `echo` `sage`, `shimmer` and `verse`. input_audio_format: type: string description: > The format of input audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`. output_audio_format: type: string description: > The format of output audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`. input_audio_transcription: type: object description: > Configuration for input audio transcription, defaults to off and can be set to `null` to turn off once on. Input audio transcription is not native to the model, since the model consumes audio directly. Transcription runs asynchronously through Whisper and should be treated as rough guidance rather than the representation understood by the model. properties: model: type: string description: > The model to use for transcription, `whisper-1` is the only currently supported model. turn_detection: type: object description: > Configuration for turn detection. Can be set to `null` to turn off. Server VAD means that the model will detect the start and end of speech based on audio volume and respond at the end of user speech. properties: type: type: string description: > Type of turn detection, only `server_vad` is currently supported. threshold: type: number description: > Activation threshold for VAD (0.0 to 1.0), this defaults to 0.5. A higher threshold will require louder audio to activate the model, and thus might perform better in noisy environments. prefix_padding_ms: type: integer description: | Amount of audio to include before the VAD detected speech (in milliseconds). Defaults to 300ms. silence_duration_ms: type: integer description: > Duration of silence to detect speech stop (in milliseconds). Defaults to 500ms. With shorter values the model will respond more quickly, but may jump in on short pauses from the user. tools: type: array description: Tools (functions) available to the model. items: type: object properties: type: type: string enum: - function description: The type of the tool, i.e. `function`. x-stainless-const: true name: type: string description: The name of the function. description: type: string description: > The description of the function, including guidance on when and how to call it, and guidance about what to tell the user when calling (if anything). parameters: type: object description: Parameters of the function in JSON Schema. tool_choice: type: string description: > How the model chooses tools. Options are `auto`, `none`, `required`, or specify a function. temperature: type: number description: > Sampling temperature for the model, limited to [0.6, 1.2]. Defaults to 0.8. max_response_output_tokens: oneOf: - type: integer - type: string enum: - inf x-stainless-const: true description: | Maximum number of output tokens for a single assistant response, inclusive of tool calls. Provide an integer between 1 and 4096 to limit output tokens, or `inf` for the maximum available tokens for a given model. Defaults to `inf`. required: - client_secret x-oaiMeta: name: The session object group: realtime example: | { "id": "sess_001", "object": "realtime.session", "model": "gpt-4o-realtime-preview-2024-12-17", "modalities": ["audio", "text"], "instructions": "You are a friendly assistant.", "voice": "alloy", "input_audio_format": "pcm16", "output_audio_format": "pcm16", "input_audio_transcription": { "model": "whisper-1" }, "turn_detection": null, "tools": [], "tool_choice": "none", "temperature": 0.7, "max_response_output_tokens": 200, "client_secret": { "value": "ek_abc123", "expires_at": 1234567890 } } securitySchemes: ApiKeyAuth: type: http scheme: bearer ```