Black Friday countdown video ad: burn the days-left text

A Black Friday countdown video needs text that changes every day, not speech, so treat it as authored overlay copy. Keep one clean clip, then send it to Sume's POST /v1/video-captions with cues such as "3 days left" at set times; the docs say this path "burns exactly that copy at those times" and skips speech-to-text.

Meta's holiday guide (published 2026-08-11, read 2026-09-30) says the deal phase uses Stories with countdown timers and CTAs, and that "Countdown overlays create Black Friday urgency". Sume facts are from Video captions and Timeline 1.0. This burns text into the file; it is not Meta's own countdown sticker.

Why not use speech captions?

Speech captions need audible speech. A silent clip fails as caption_no_speech with next_action: use_overlay_captions. Authored cues (or segments) with text, start and end avoid that, and they are mutually exclusive with words and script_text. For styling options, see customize burned-in captions.

How do I make one cue set per day?

Loop over the days left and call the caption endpoint on the same clean source each time. Each call is one job with its own Idempotency-Key, and the source is never regenerated.

const clean = "https://media.sume.com/artifacts/example/clean.mp4";
for (const daysLeft of [3, 2, 1]) {
  const res = await fetch("https://api.sume.com/v1/video-captions", {
    method: "POST",
    headers: {
      Authorization: "Bearer " + process.env.SUME_API_KEY,
      "Content-Type": "application/json",
      "Idempotency-Key": "bf-countdown-" + daysLeft,
    },
    body: JSON.stringify({
      video_url: clean,
      style: "punch",
      cues: [{ text: daysLeft + " days left", start: 0, end: 4 }],
    }),
  });
  console.log(daysLeft, res.status);
}

What does each version cost and how long can it be?

Where does the clean clip come from?

Anywhere that ends as a Sume-hosted media.sume.com file: a Format run, a video job, or a Timeline render. Make the vertical cut once, then caption it per day. The four-phase plan this belongs to is in holiday ad creative by phase.