How do I parse a Model API stream with fetch?

Without the SDK, read server-sent events yourself. Each event is a data: line; the stream ends with data: [DONE]. Check every event for an error.

const res = await fetch("https://api.gateway.clatterlabs.xyz/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.CLATTER_API_KEY}`,
    "X-Clatter-Account": process.env.CLATTER_ACCOUNT_ID,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ model: "supercosmos-flash", stream: true,
    messages: [{ role: "user", content: "Count to five." }] }),
});
const reader = res.body.getReader();
const dec = new TextDecoder();
let buf = "";
for (;;) {
  const { value, done } = await reader.read();
  if (done) break;
  buf += dec.decode(value, { stream: true });
  let i;
  while ((i = buf.indexOf("\n")) >= 0) {
    const line = buf.slice(0, i).trim(); buf = buf.slice(i + 1);
    if (!line.startsWith("data:")) continue;
    const payload = line.slice(5).trim();
    if (payload === "[DONE]") break;
    const ev = JSON.parse(payload);
    if (ev.error) throw new Error(ev.error.code);
    const t = ev.choices?.[0]?.delta?.content;
    if (t) process.stdout.write(t);
  }
}

A failure partway sends a data: {"error": ...} event and then data: [DONE].

Every JavaScript example uses the same client (base URL, key and the X-Clatter-Account header); see Set up the JavaScript SDK. Full parameter list: Create a chat completion.

Still need help?#

• General support: support@clatterlabs.com or team@clatterlabs.xyz
• Infrastructure questions, or permanent deletion of your data (your whole account or one service): infrastructure@clatterlabs.xyz

We usually reply within the first hour, and always within 24 hours. A full support team is with you.