Mist v3 HTTP API | Low-Latency Streaming TTS

curl --request POST \
  --url https://mist.api.rime.ai/ \
  --header 'Accept: audio/webm;codecs=opus' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --output output.webm \
  --fail \
  --data '{
  "text": "Hello from Rime!",
  "speaker": "cove",
  "lang": "en",
  "samplingRate": 24000
}'

import requests

url = "https://mist.api.rime.ai/"

payload = {
    "speaker": "cove",
    "text": "Hello from Rime!",
    "samplingRate": 24000
}
headers = {
    "Accept": "audio/webm;codecs=opus",
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
}

with requests.post(url, headers=headers, json=payload, stream=True) as response:
    response.raise_for_status()
    with open("output.webm", "wb") as f:
        for chunk in response.iter_content(chunk_size=4096):
            if chunk:
                f.write(chunk)

const fs = require("fs");

const options = {
  method: 'POST',
  headers: {
    Accept: 'audio/webm;codecs=opus',
    Authorization: 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: '{"speaker":"cove","text":"Hello from Rime!","samplingRate":24000}'
};

fetch('https://mist.api.rime.ai/', options)
  .then(response => response.arrayBuffer())
  .then(buffer => {
    fs.writeFileSync("output.webm", Buffer.from(buffer));
    console.log("Audio saved to output.webm");
  })
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://mist.api.rime.ai/",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}",
  CURLOPT_HTTPHEADER => [
    "Accept: audio/webm;codecs=opus",
    "Authorization: Bearer YOUR_API_KEY",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
  "io"
  "net/http"
  "os"
  "strings"
)

func main() {

  url := "https://mist.api.rime.ai/"

  payload := strings.NewReader("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")

  req, _ := http.NewRequest("POST", url, payload)

  req.Header.Add("Accept", "audio/webm;codecs=opus")
  req.Header.Add("Authorization", "Bearer YOUR_API_KEY")
  req.Header.Add("Content-Type", "application/json")

  res, _ := http.DefaultClient.Do(req)

  defer res.Body.Close()
  body, _ := io.ReadAll(res.Body)

  _ = os.WriteFile("output.webm", body, 0644)
}

HttpResponse<byte[]> response = Unirest.post("https://mist.api.rime.ai/")
  .header("Accept", "audio/webm;codecs=opus")
  .header("Authorization", "Bearer YOUR_API_KEY")
  .header("Content-Type", "application/json")
  .body("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")
  .asBytes();
Files.write(Paths.get("output.webm"), response.getBody());

curl --request POST \
  --url https://mist.api.rime.ai/ \
  --header 'Accept: audio/webm;codecs=opus' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --output output.webm \
  --fail \
  --data '{
  "text": "Hello from Rime!",
  "speaker": "cove",
  "lang": "en",
  "samplingRate": 24000
}'

import requests

url = "https://mist.api.rime.ai/"

payload = {
    "speaker": "cove",
    "text": "Hello from Rime!",
    "samplingRate": 24000
}
headers = {
    "Accept": "audio/webm;codecs=opus",
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
}

with requests.post(url, headers=headers, json=payload, stream=True) as response:
    response.raise_for_status()
    with open("output.webm", "wb") as f:
        for chunk in response.iter_content(chunk_size=4096):
            if chunk:
                f.write(chunk)

const fs = require("fs");

const options = {
  method: 'POST',
  headers: {
    Accept: 'audio/webm;codecs=opus',
    Authorization: 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: '{"speaker":"cove","text":"Hello from Rime!","samplingRate":24000}'
};

fetch('https://mist.api.rime.ai/', options)
  .then(response => response.arrayBuffer())
  .then(buffer => {
    fs.writeFileSync("output.webm", Buffer.from(buffer));
    console.log("Audio saved to output.webm");
  })
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://mist.api.rime.ai/",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}",
  CURLOPT_HTTPHEADER => [
    "Accept: audio/webm;codecs=opus",
    "Authorization: Bearer YOUR_API_KEY",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
  "io"
  "net/http"
  "os"
  "strings"
)

func main() {

  url := "https://mist.api.rime.ai/"

  payload := strings.NewReader("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")

  req, _ := http.NewRequest("POST", url, payload)

  req.Header.Add("Accept", "audio/webm;codecs=opus")
  req.Header.Add("Authorization", "Bearer YOUR_API_KEY")
  req.Header.Add("Content-Type", "application/json")

  res, _ := http.DefaultClient.Do(req)

  defer res.Body.Close()
  body, _ := io.ReadAll(res.Body)

  _ = os.WriteFile("output.webm", body, 0644)
}

HttpResponse<byte[]> response = Unirest.post("https://mist.api.rime.ai/")
  .header("Accept", "audio/webm;codecs=opus")
  .header("Authorization", "Bearer YOUR_API_KEY")
  .header("Content-Type", "application/json")
  .body("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")
  .asBytes();
Files.write(Paths.get("output.webm"), response.getBody());

The Rime API authenticates every request with a bearer token in the Authorization header: Authorization: Bearer YOUR_API_KEY. See API authentication for how to create a key. The endpoint streams audio in the format you name in the Accept header. Always set it, because a request without Accept returns 400. A wildcard (*/*) returns WAV, and so does a type the API can’t stream.

Audio formats

Set the Accept header to one of the following values:

Format	Accept Header	Notes
Opus (WebM)	`audio/webm;codecs=opus`	Recommended. Smaller files than MP3 at comparable quality. WebM streams natively in browsers.
Opus (OGG)	`audio/ogg;codecs=opus`	Opus in an OGG container. Smaller files than MP3 at comparable quality.
MP3	`audio/mpeg`	Lower compression rate than Opus. Highest compatibility across devices and players.
WAV	`audio/wav`	Uncompressed. RIFF WAVE header with 16-bit little-endian linear PCM samples. Streams natively in browsers.
PCM	`audio/L16`	Headerless 16-bit little-endian linear PCM. A chunk can end mid-sample, so keep whole samples.
G.711 μ-law	`audio/PCMU`	Headerless stream of audio bytes.

Deprecated aliases

The API still accepts these for backward compatibility. Use the RFC types above in new code.

Deprecated	Use instead
`audio/mp3`	`audio/mpeg`
`audio/pcm`	`audio/L16`
`audio/x-mulaw`	`audio/PCMU`

Variable parameters

string

A voice from the Rime voice catalog. If you leave it out, Mist v3 uses one default voice for the language. Set it to choose the voice.

string

required

The text you’d like spoken. Character limit per request is 1,000 via the API and in the dashboard UI.

number

default:"24000"

The sampling rate (Hz).

number

default:"1.0"

The time scaling factor. Accepted range is 0.4 to 2.5. Values outside this range are clamped without an error.Values above 1.0 slow the audio down, and values below 1.0 speed it up.

string

default:"en"

If provided, the language must match the language spoken by the selected speaker. Verify the pairing in the Rime voice catalog.

bool

default:"false"

When set to true, adds pauses between words enclosed in angle brackets. The number inside the brackets specifies the pause duration in milliseconds. Example: Hi. <200> I'd love to have a conversation with you. adds a 200ms pause. Learn more about custom pauses.

string

Comma-separated list of speed values applied to words in square brackets. Values < 1.0 speed up speech, > 1.0 slow it down. Example: “This is [slow] and [fast]”, use “3, 0.5” to make “slow” slower and “fast” faster.

curl --request POST \
  --url https://mist.api.rime.ai/ \
  --header 'Accept: audio/webm;codecs=opus' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --output output.webm \
  --fail \
  --data '{
  "text": "Hello from Rime!",
  "speaker": "cove",
  "lang": "en",
  "samplingRate": 24000
}'

import requests

url = "https://mist.api.rime.ai/"

payload = {
    "speaker": "cove",
    "text": "Hello from Rime!",
    "samplingRate": 24000
}
headers = {
    "Accept": "audio/webm;codecs=opus",
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
}

with requests.post(url, headers=headers, json=payload, stream=True) as response:
    response.raise_for_status()
    with open("output.webm", "wb") as f:
        for chunk in response.iter_content(chunk_size=4096):
            if chunk:
                f.write(chunk)

const fs = require("fs");

const options = {
  method: 'POST',
  headers: {
    Accept: 'audio/webm;codecs=opus',
    Authorization: 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: '{"speaker":"cove","text":"Hello from Rime!","samplingRate":24000}'
};

fetch('https://mist.api.rime.ai/', options)
  .then(response => response.arrayBuffer())
  .then(buffer => {
    fs.writeFileSync("output.webm", Buffer.from(buffer));
    console.log("Audio saved to output.webm");
  })
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://mist.api.rime.ai/",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}",
  CURLOPT_HTTPHEADER => [
    "Accept: audio/webm;codecs=opus",
    "Authorization: Bearer YOUR_API_KEY",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
  "io"
  "net/http"
  "os"
  "strings"
)

func main() {

  url := "https://mist.api.rime.ai/"

  payload := strings.NewReader("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")

  req, _ := http.NewRequest("POST", url, payload)

  req.Header.Add("Accept", "audio/webm;codecs=opus")
  req.Header.Add("Authorization", "Bearer YOUR_API_KEY")
  req.Header.Add("Content-Type", "application/json")

  res, _ := http.DefaultClient.Do(req)

  defer res.Body.Close()
  body, _ := io.ReadAll(res.Body)

  _ = os.WriteFile("output.webm", body, 0644)
}

HttpResponse<byte[]> response = Unirest.post("https://mist.api.rime.ai/")
  .header("Accept", "audio/webm;codecs=opus")
  .header("Authorization", "Bearer YOUR_API_KEY")
  .header("Content-Type", "application/json")
  .body("{\n  \"speaker\": \"cove\",\n  \"text\": \"Hello from Rime!\",\n  \"samplingRate\": 24000\n}")
  .asBytes();
Files.write(Paths.get("output.webm"), response.getBody());

Overview

Coda API reference

Mist v3 API reference

Speech-to-text API reference

API Metadata

Other APIs

Streaming HTTP

Audio formats

Deprecated aliases

Variable parameters

​Audio formats

​Deprecated aliases

​Variable parameters

Audio formats

Deprecated aliases

Variable parameters