Your agent writes once. Everyone understands it.

# 1. Create a key in the console below, then:
curl https://vocaic.example/api/v1/deliver \
  -H "Authorization: Bearer vk_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "message": "Your appointment moved to 3:40 pm. Reply yes to confirm.",
    "language": "en",
    "recipients": [
      { "id": "wei",    "language": "en", "accent": "zh-CN", "mode": "voice" },
      { "id": "priya",  "language": "hi", "mode": "text" },
      { "id": "oliver", "language": "en", "accent": "en-GB", "mode": "voice" }
    ]
  }'

const res = await fetch("https://vocaic.example/api/v1/deliver", {
  method: "POST",
  headers: {
    "Authorization": "Bearer vk_live_your_key",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    message: "Your appointment moved to 3:40 pm. Reply yes to confirm.",
    language: "en",
    recipients: [
      { id: "wei", language: "en", accent: "zh-CN", mode: "voice" },
      { id: "priya", language: "hi", mode: "text" },
    ],
  }),
});
const { deliveries } = await res.json();
// deliveries[0].audioUrl is a playable MP3 for voice recipients.

import requests

res = requests.post(
    "https://vocaic.example/api/v1/deliver",
    headers={"Authorization": "Bearer vk_live_your_key"},
    json={
        "message": "Your appointment moved to 3:40 pm. Reply yes to confirm.",
        "language": "en",
        "recipients": [
            {"id": "wei", "language": "en", "accent": "zh-CN", "mode": "voice"},
            {"id": "priya", "language": "hi", "mode": "text"},
        ],
    },
)
deliveries = res.json()["deliveries"]

curl https://vocaic.example/api/v1/replies \
  -H "Authorization: Bearer vk_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{ "from": "priya", "mode": "text", "language": "hi-IN", "text": "हाँ, मैं पुष्टि करता हूँ।" }'
# -> { "ok": true, "text": "Yes, I confirm.", "language": "hi-IN", "mode": "text", "translated": true }

# Synthesize spoken English in a chosen accent, get an MP3 back:
curl https://vocaic.example/api/v1/speech \
  -H "Authorization: Bearer vk_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{ "text": "Your table is ready. Please come to the front desk.", "accent": "en-IN" }' \
  --output hello.mp3
# Give one of: voiceId (en-GB-Sonia), accent (british, en-IN, zh-CN), or language (ja-JP).

const res = await fetch("https://vocaic.example/api/v1/translate", {
  method: "POST",
  headers: {
    "Authorization": "Bearer vk_live_your_key",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ text: "Welcome, your order is on its way.", target: "es-ES" }),
});
const { text, translated } = await res.json();
// text: "Bienvenido, su pedido esta en camino."  (source defaults to English)

curl https://vocaic.example/api/v1/usage \
  -H "Authorization: Bearer vk_live_your_key"
# -> { "ok": true, "usage": { "day": "2026-10-03", "used": 42, "remaining": 4958,
#        "limit": 5000, "perMinute": 60, "recipientsPerCall": 10, "resetsAt": "..." } }

Vocaic-Signature: t=1764800000, v1=4a7f...e2  (hex HMAC-SHA256 of `${t}.${rawBody}`)

import crypto from "node:crypto";

// Express-style handler. Use the RAW request body (not a re-serialized object).
export function handler(req, res) {
  const header = req.get("Vocaic-Signature") || "";
  const parts = Object.fromEntries(header.split(",").map((p) => p.trim().split("=")));
  const t = Number(parts.t);
  const raw = req.rawBody; // the exact bytes Vocaic sent

  // Reject old timestamps (5 minute tolerance) to stop replays.
  if (!t || Math.abs(Date.now() / 1000 - t) > 300) return res.status(400).end();

  const expected = crypto
    .createHmac("sha256", process.env.VOCAIC_WEBHOOK_SECRET)
    .update(t + "." + raw)
    .digest("hex");

  const ok = parts.v1 && crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(parts.v1));
  if (!ok) return res.status(400).end();

  const event = JSON.parse(raw); // { id, event, created, data }
  // event.event is "delivery.created" or "reply.created".
  res.status(200).end(); // a 2xx tells Vocaic the delivery succeeded
}

<!-- Put this where you want the player, then add the script. -->
<article>
  <h1>Your article title</h1>
  <p>Your first paragraph...</p>
  <p>Your second paragraph...</p>
</article>

<script
  src="https://vocaic.example/sdk/vocaic-reader.js"
  data-article="article"
  data-voice="en-GB-Sonia"
  defer></script>

<script src="https://vocaic.example/sdk/vocaic-reader.js" data-auto="false"></script>
<script>
  VocaicReader.mount({
    articleSelector: "#post-body",   // where your article is
    mount: "#listen",                // where to put the player
    voiceId: "en-IN-Neerja",   // optional reading voice
  });
</script>