Transcribe a short audio file
curl --request POST \
--url https://sync.assemblyai.com/transcribe \
--header 'Authorization: <api-key>' \
--header 'Content-Type: multipart/form-data' \
--header 'X-AAI-Model: <x-aai-model>' \
--form audio='@example-file' \
--form 'config={
"prompt": "<string>",
"keyterms_prompt": [
"<string>"
],
"conversation_context": "<string>",
"language_code": "en"
}'import requests
url = "https://sync.assemblyai.com/transcribe"
files = { "audio": ("example-file", open("example-file", "rb")) }
payload = { "config": "{
\"prompt\": \"<string>\",
\"keyterms_prompt\": [
\"<string>\"
],
\"conversation_context\": \"<string>\",
\"language_code\": \"en\"
}" }
headers = {
"X-AAI-Model": "<x-aai-model>",
"Authorization": "<api-key>"
}
response = requests.post(url, data=payload, files=files, headers=headers)
print(response.text)const form = new FormData();
form.append('audio', '<string>');
form.append('config', '{
"prompt": "<string>",
"keyterms_prompt": [
"<string>"
],
"conversation_context": "<string>",
"language_code": "en"
}');
const options = {
method: 'POST',
headers: {'X-AAI-Model': '<x-aai-model>', Authorization: '<api-key>'}
};
options.body = form;
fetch('https://sync.assemblyai.com/transcribe', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://sync.assemblyai.com/transcribe",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--",
CURLOPT_HTTPHEADER => [
"Authorization: <api-key>",
"Content-Type: multipart/form-data",
"X-AAI-Model: <x-aai-model>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://sync.assemblyai.com/transcribe"
payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("X-AAI-Model", "<x-aai-model>")
req.Header.Add("Authorization", "<api-key>")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.post("https://sync.assemblyai.com/transcribe")
.header("X-AAI-Model", "<x-aai-model>")
.header("Authorization", "<api-key>")
.body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--")
.asString();require 'uri'
require 'net/http'
url = URI("https://sync.assemblyai.com/transcribe")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["X-AAI-Model"] = '<x-aai-model>'
request["Authorization"] = '<api-key>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--"
response = http.request(request)
puts response.read_body{
"text": "Hi, I'm calling about my Best Buy order...",
"words": [
{
"text": "Hi",
"start": 0,
"end": 200,
"confidence": 0.91
},
{
"text": "I'm",
"start": 220,
"end": 320,
"confidence": 0.88
}
],
"confidence": 0.87,
"audio_duration_ms": 101567,
"session_id": "eb92c4ff-4bbb-429f-9b99-7279d7fe738f"
}{
"message": "<string>"
}{
"detail": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}{
"detail": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}API reference
Transcribe a short audio file
POST
/
transcribe
Transcribe a short audio file
curl --request POST \
--url https://sync.assemblyai.com/transcribe \
--header 'Authorization: <api-key>' \
--header 'Content-Type: multipart/form-data' \
--header 'X-AAI-Model: <x-aai-model>' \
--form audio='@example-file' \
--form 'config={
"prompt": "<string>",
"keyterms_prompt": [
"<string>"
],
"conversation_context": "<string>",
"language_code": "en"
}'import requests
url = "https://sync.assemblyai.com/transcribe"
files = { "audio": ("example-file", open("example-file", "rb")) }
payload = { "config": "{
\"prompt\": \"<string>\",
\"keyterms_prompt\": [
\"<string>\"
],
\"conversation_context\": \"<string>\",
\"language_code\": \"en\"
}" }
headers = {
"X-AAI-Model": "<x-aai-model>",
"Authorization": "<api-key>"
}
response = requests.post(url, data=payload, files=files, headers=headers)
print(response.text)const form = new FormData();
form.append('audio', '<string>');
form.append('config', '{
"prompt": "<string>",
"keyterms_prompt": [
"<string>"
],
"conversation_context": "<string>",
"language_code": "en"
}');
const options = {
method: 'POST',
headers: {'X-AAI-Model': '<x-aai-model>', Authorization: '<api-key>'}
};
options.body = form;
fetch('https://sync.assemblyai.com/transcribe', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://sync.assemblyai.com/transcribe",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--",
CURLOPT_HTTPHEADER => [
"Authorization: <api-key>",
"Content-Type: multipart/form-data",
"X-AAI-Model: <x-aai-model>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://sync.assemblyai.com/transcribe"
payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("X-AAI-Model", "<x-aai-model>")
req.Header.Add("Authorization", "<api-key>")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.post("https://sync.assemblyai.com/transcribe")
.header("X-AAI-Model", "<x-aai-model>")
.header("Authorization", "<api-key>")
.body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--")
.asString();require 'uri'
require 'net/http'
url = URI("https://sync.assemblyai.com/transcribe")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["X-AAI-Model"] = '<x-aai-model>'
request["Authorization"] = '<api-key>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"config\"\r\n\r\n{\r\n \"prompt\": \"<string>\",\r\n \"keyterms_prompt\": [\r\n \"<string>\"\r\n ],\r\n \"conversation_context\": \"<string>\",\r\n \"language_code\": \"en\"\r\n}\r\n-----011000010111000001101001--"
response = http.request(request)
puts response.read_body{
"text": "Hi, I'm calling about my Best Buy order...",
"words": [
{
"text": "Hi",
"start": 0,
"end": 200,
"confidence": 0.91
},
{
"text": "I'm",
"start": 220,
"end": 320,
"confidence": 0.88
}
],
"confidence": 0.87,
"audio_duration_ms": 101567,
"session_id": "eb92c4ff-4bbb-429f-9b99-7279d7fe738f"
}{
"message": "<string>"
}{
"detail": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}{
"detail": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}{
"message": "<string>"
}Authorizations
Your AssemblyAI API key. Optionally prefixed with Bearer. Also accepted as the token query parameter.
Headers
Model identifier used for request routing. The canonical value is universal-3-5-pro; u3-sync-pro and u3-pro are accepted as legacy aliases.
Available options:
universal-3-5-pro Query Parameters
API key alternative for clients that cannot set the Authorization header. The header wins when both are present.
Body
multipart/form-data
Response
Transcription completed successfully.
Full transcript of the audio.
Word-level timestamps and confidence scores.
Show child attributes
Show child attributes
Overall transcript confidence (0–1).
Duration of the submitted audio in milliseconds.
Server-generated request identifier. Include this in support requests.
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