curl -X PATCH 'https://api.elevenlabs.io/v1/speech-engine/speech-engine-id' \
  -H "xi-api-key: $ELEVENLABS_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "example-name",
  "speech_engine": {
    "ws_url": "example-ws-url",
    "request_headers": {}
  },
  "asr": {
    "keywords": [
      "hello",
      "world"
    ],
    "provider": "scribe_realtime",
    "quality": "high",
    "user_input_audio_format": "pcm_16000"
  },
  "tts": {
    "agent_output_audio_format": "pcm_16000",
    "model_id": "eleven_turbo_v2",
    "optimize_streaming_latency": 3,
    "pronunciation_dictionary_locators": [],
    "similarity_boost": 0.8,
    "speed": 1,
    "stability": 0.5,
    "voice_id": "cjVigY5qzO86Huf0OWal"
  },
  "turn": {
    "interruption_ignore_term_languages": [],
    "interruption_ignore_terms": [],
    "merge_with_default_ignore_terms": false,
    "mode": "turn",
    "retranscribe_on_turn_timeout": false,
    "silence_end_call_timeout": -1,
    "speculative_turn": false,
    "spelling_patience": "auto",
    "transcribe_on_disabled_interruptions": false,
    "turn_eagerness": "normal",
    "turn_timeout": 7
  },
  "vad": {
    "background_voice_detection": false
  },
  "conversation": {
    "client_events": [
      "audio",
      "interruption"
    ],
    "max_duration_seconds": 600
  },
  "privacy": {
    "apply_to_existing_conversations": false,
    "delete_audio": false,
    "delete_transcript_and_pii": false,
    "record_voice": true,
    "retention_days": -1,
    "zero_retention_mode": false
  },
  "call_limits": {
    "agent_concurrency_limit": -1,
    "bursting_enabled": true,
    "daily_limit": 100000
  },
  "language": "example-language",
  "cascade_timeout_seconds": 0,
  "tags": [
    "example-tags"
  ],
  "overrides": {
    "first_message": false
  }
}'

# PATCH /v1/speech-engine/{speech_engine_id} (ElevenLabs API)
Base URL: https://api.elevenlabs.io
Auth: xi-api-key: <ELEVENLABS_API_KEY>
Last verified: 2026-10-20

> Update Speech Engine

## Critical Gotchas
* Authentication uses the non-standard `xi-api-key` header, not `Authorization: Bearer`. Sending a Bearer token returns HTTP 401.
* Text-to-speech responses are raw binary audio, not JSON. Write the body to a file (`--output speech.mp3`) rather than parsing it.

## cURL
curl -X PATCH 'https://api.elevenlabs.io/v1/speech-engine/speech-engine-id' \
  -H "xi-api-key: $ELEVENLABS_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{"name":"example-name","speech_engine":{"ws_url":"example-ws-url","request_headers":{}}}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| speech_engine_id | path | string | Yes | The speech engine ID (accepts seng_ o... |
| name | body | string | No | Request body field name. |
| speech_engine | body | object | No | Request body field speech_engine. |
Other params: asr, tts, turn, vad, conversation, privacy, call_limits, language, cascade_timeout_seconds, tags, overrides

## Response (200 OK)
{"asr":{"keywords":[],"provider":"elevenlabs"},"call_limits":{"agent_concurrency_limit":-1,"bursting_enabled":true}}

---
Need an API key? Get one at https://elevenlabs.io/app/sign-up

PATCH

PATCH /v1/speech-engine/{speech_engine_id} — ElevenLabs API

ElevenLabs API

Update Speech Engine

Base URL: https://api.elevenlabs.io
Auth: xi-api-key: <ELEVENLABS_API_KEY>
Last verified: 2026-10-20 · upstream hash matched

Actions Try in browser→

Agents: curl -H "Accept: text/markdown" this URL
→ 224 tokens · Vary: Accept

Critical gotchas

Authentication uses the non-standard xi-api-key header, not Authorization: Bearer. Sending a Bearer token returns HTTP 401.

Text-to-speech responses are raw binary audio, not JSON. Write the body to a file (--output speech.mp3) rather than parsing it.

cURL

curl -X PATCH 'https://api.elevenlabs.io/v1/speech-engine/speech-engine-id' \  -H "xi-api-key: $ELEVENLABS_API_KEY" \  -H 'Content-Type: application/json' \  -d '{  "name": "example-name",  "speech_engine": {    "ws_url": "example-ws-url",    "request_headers": {}  },  "asr": {    "keywords": [      "hello",      "world"    ],    "provider": "scribe_realtime",    "quality": "high",    "user_input_audio_format": "pcm_16000"  },  "tts": {    "agent_output_audio_format": "pcm_16000",    "model_id": "eleven_turbo_v2",    "optimize_streaming_latency": 3,    "pronunciation_dictionary_locators": [],    "similarity_boost": 0.8,    "speed": 1,    "stability": 0.5,    "voice_id": "cjVigY5qzO86Huf0OWal"  },  "turn": {    "interruption_ignore_term_languages": [],    "interruption_ignore_terms": [],    "merge_with_default_ignore_terms": false,    "mode": "turn",    "retranscribe_on_turn_timeout": false,    "silence_end_call_timeout": -1,    "speculative_turn": false,    "spelling_patience": "auto",    "transcribe_on_disabled_interruptions": false,    "turn_eagerness": "normal",    "turn_timeout": 7  },  "vad": {    "background_voice_detection": false  },  "conversation": {    "client_events": [      "audio",      "interruption"    ],    "max_duration_seconds": 600  },  "privacy": {    "apply_to_existing_conversations": false,    "delete_audio": false,    "delete_transcript_and_pii": false,    "record_voice": true,    "retention_days": -1,    "zero_retention_mode": false  },  "call_limits": {    "agent_concurrency_limit": -1,    "bursting_enabled": true,    "daily_limit": 100000  },  "language": "example-language",  "cascade_timeout_seconds": 0,  "tags": [    "example-tags"  ],  "overrides": {    "first_message": false  }}'

Parameters

Name	In	Type	Required	Description
speech_engine_id	path	string	Yes	The speech engine ID (accepts seng_ or agent_ prefix)
name	body	string	No	Request body field name.
speech_engine	body	object	No	Request body field speech_engine.
asr	body	object	No	Request body field asr.
tts	body	object	No	Request body field tts.
turn	body	object	No	Request body field turn.
vad	body	object	No	Request body field vad.
conversation	body	object	No	Request body field conversation.
privacy	body	object	No	Request body field privacy.
call_limits	body	object	No	Request body field call_limits.
language	body	string	No	Request body field language.
cascade_timeout_seconds	body	number	No	Time in seconds to wait for the upstream speech engine endpoint to respond before the attempt is abandoned and retried. Must be between 2 and 15 seconds.
tags	body	string[]	No	Request body field tags.
overrides	body	object	No	Request body field overrides.

Response 200 OK

{
  "asr": {
    "keywords": [],
    "provider": "elevenlabs",
    "quality": "high",
    "user_input_audio_format": "pcm_16000"
  },
  "call_limits": {
    "agent_concurrency_limit": -1,
    "bursting_enabled": true,
    "daily_limit": 100000
  },
  "cascade_timeout_seconds": 4,
  "conversation": {
    "client_events": [
      "audio",
      "interruption",
      "agent_response",
      "user_transcript"
    ],
    "max_duration_seconds": 600
  },
  "language": "en",
  "metadata": {
    "created_at_unix_secs": 1714000000,
    "created_from": "api",
    "last_updated_from": "api",
    "updated_at_unix_secs": 1714000000
  },
  "name": "My Speech Engine",
  "overrides": {
    "first_message": false
  },
  "privacy": {
    "apply_to_existing_conversations": false,
    "delete_audio": false,
    "delete_transcript_and_pii": false,
    "record_voice": true,
    "retention_days": -1,
    "zero_retention_mode": false
  },
  "speech_engine": {
    "request_headers": {},
    "ws_url": "wss://example.com/transcript"
  },
  "speech_engine_id": "seng_3701k3ttaq12ewp8b7qv5rfyszkz",
  "tags": [
    "production",
    "v1"
  ],
  "tts": {
    "agent_output_audio_format": "pcm_16000",
    "model_id": "eleven_flash_v2",
    "optimize_streaming_latency": 3,
    "similarity_boost": 0.8,
    "speed": 1,
    "stability": 0.5,
    "voice_id": "cjVigY5qzO86Huf0OWal"
  },
  "turn": {
    "mode": "turn",
    "silence_end_call_timeout": -1,
    "turn_eagerness": "normal",
    "turn_timeout": 7
  },
  "vad": {
    "background_voice_detection": false
  }
}

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