by OpenAI

TTS-1 HD turns finished copy into quality-focused narration, with preset voices and selectable compressed or uncompressed audio.

openai/tts-1-hd/text-to-speech
  • 9 voices
  • Text to Speech

Call it with the model name openai/tts-1-hd/text-to-speech on POST /jobs/createTask, from $0.006.

Model nameopenai/tts-1-hd/text-to-speech
EndpointPOST https://api.popnow.ai/api/v1/jobs/createTask
# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "openai/tts-1-hd/text-to-speech",
  "input": {
    "text": "Welcome back. Your files finished rendering a minute ago and are ready to download.",
    "voice_id": "alloy"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

The input is built from the schema below, so it passes validation as written. Change the prompt and links to your own.

Price

OptionUSD per 1,000 characters
Standard$0.006

Billed in USD · Every option and its price: GET /models/openai/tts-1-hd/text-to-speech

Limits

Text length (characters)
4,096
Voices
9

Parameters

These fields come from the same schema we check every request against. Fields that are not listed are rejected.

  • textstringRequiredChanges the price

    The words to be spoken, exactly as written.

    Range
    Character count: 1 – 4096
  • voice_idstringOptional

    Pick from the available voices.

    Default
    "alloy"
    Allowed values
    "alloy""ash""coral""echo""fable""onyx""nova""sage""shimmer"
  • speednumberOptional

    Speaking pace.

    Default
    1
    Range
    0.25 – 4
  • output_formatstringOptional

    File type of the result.

    Default
    "mp3"
    Allowed values
    "mp3""opus""aac""flac""wav""pcm"
Raw JSON Schema
{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "text": {
      "type": "string",
      "maxLength": 4096,
      "minLength": 1,
      "description": "Words to be spoken; spaces and punctuation count as characters."
    },
    "speed": {
      "type": "number",
      "default": 1,
      "maximum": 4,
      "minimum": 0.25,
      "description": "Speaking speed multiplier."
    },
    "voice_id": {
      "enum": [
        "alloy",
        "ash",
        "coral",
        "echo",
        "fable",
        "onyx",
        "nova",
        "sage",
        "shimmer"
      ],
      "type": "string",
      "default": "alloy",
      "description": "Built-in voice for this Speech model."
    },
    "output_format": {
      "enum": [
        "mp3",
        "opus",
        "aac",
        "flac",
        "wav",
        "pcm"
      ],
      "type": "string",
      "default": "mp3",
      "description": "Audio file encoding; pcm is raw 24 kHz 16-bit little-endian audio."
    }
  },
  "additionalProperties": false
}

Responses, polling and callbacks

Every model works the same way: create a task, then poll it or wait for a callback.

Price it first

cURL
curl -X POST https://api.popnow.ai/api/v1/jobs/quote \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "openai/tts-1-hd/text-to-speech",
  "input": {
    "text": "Welcome back. Your files finished rendering a minute ago and are ready to download.",
    "voice_id": "alloy"
  }
}'

Send the same request body to POST /jobs/quote to see the estimated and maximum USD charge before running. A quote does not run the task or charge your balance.

Accepted

HTTP
HTTP/1.1 202 Accepted

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "state": "queued"
  },
  "request_id": "req_example_create"
}

HTTP 202 means accepted: the maximum USD amount is held until settlement. When a task is accepted, we reserve the maximum quoted amount from your API balance. On completion, we charge for actual usage, never more than the hold, and release the remainder. If the task fails, the hold is released.

Check status

cURL
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Poll every few seconds with backoff and stop once state is succeeded, failed, canceled or expired.

Finished task

JSON
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "openai/tts-1-hd/text-to-speech",
    "state": "succeeded",
    "output": {
      "assets": [
        {
          "url": "https://cdn.popnow.ai/tasks/task_01k3m8x9q2z4v7n5p6r8s0t1w3/output.mp3?signature=FROM_RESPONSE",
          "expiresAt": "2026-10-17T12:20:00Z",
          "mime": "audio/mpeg",
          "durationSeconds": 30
        }
      ]
    },
    "settled": true
  },
  "request_id": "req_example_record"
}

Download from url before expiresAt. Need a fresh link later? Ask POST /common/download-url.

Verify a callback

Node.js
import { createHash, createHmac, timingSafeEqual } from "node:crypto";
import express from "express";

const app = express();
// express.raw keeps the exact bytes that were signed; express.json would not match.
app.post("/hooks/popnow", express.raw({ type: "application/json" }), (req, res) => {
  const timestamp = req.header("X-Webhook-Timestamp");
  const signature = req.header("X-Webhook-Signature") ?? "";
  const body = JSON.parse(req.body.toString("utf8"));
  const taskId = body.data?.taskId ?? body.task_id;
  const digest = createHash("sha256").update(req.body).digest("hex");
  const expected = createHmac("sha256", process.env.POPNOW_WEBHOOK_SECRET)
    .update(`${taskId}.${timestamp}.${digest}`)
    .digest("base64");
  const ok = expected.length === signature.length && timingSafeEqual(Buffer.from(expected), Buffer.from(signature));
  // Check the signature first, then reject anything older than five minutes.
  if (!ok || Math.abs(Date.now() / 1000 - Number(timestamp)) > 300) return res.status(401).end();
  res.status(200).end(); // answer fast, then fetch the task and store its files
});

With callBackUrl set, we post the finished task to you. Check the signature against the raw body before you trust it.

Send a local file

cURL
curl -X POST https://api.popnow.ai/api/v1/common/upload-url \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"contentType": "image/png", "bytes": 482113}'

# PUT the file bytes to data.uploadUrl with every header in data.headers, then commit it:
curl -X POST https://api.popnow.ai/api/v1/files/$FILE_ID/commit \
  -H "Authorization: Bearer $POPNOW_API_KEY"
# The commit returns a popnow://f/... reference. Put it in any image, video or
# audio field of the task input instead of a public https URL.

Public https links work as they are. Local files go through upload-url and commit first.