Nextdoor video ad specs: MP4 or MOV, 500 MB, 2 to 300 seconds

Nextdoor video ads are MOV or MP4 files of up to 500 MB and 2 to 300 seconds, in 16:9 or 1:1, for the Newsfeed placement only. Nextdoor auto-generates the thumbnail. It recommends clips under 30 seconds with subtitles. Specs are from Nextdoor, read 2026-10-01.

What does Nextdoor require for video ads?

How do I render a 16:9 or 1:1 Nextdoor clip with Sume?

Timeline 1.0 (POST /v1/timeline-1.0/render) takes output.width and output.height as even integers from 256 to 2160 and output.fps of 24, 25, 30 or 60, or omits fps to match the sources. It needs an Idempotency-Key, accepts only media.sume.com sources, and returns one MP4 at $0.10 per output minute, rounded up. The unbilled POST /v1/timeline-1.0/plan previews the cost first.

For 16:9 use 1280x720 or 1920x1080. For 1:1 use 1080x1080. All are even and inside the 256 to 2160 range. Remember that the default output is vertical 1080x1920, which Nextdoor does not list.

curl -X POST https://api.sume.com/v1/timeline-1.0/render \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: nextdoor-square-001" \
  -d '{
    "audio": { "mode": "silence", "duration_seconds": 20 },
    "output": { "width": 1080, "height": 1080, "fps": 30 },
    "video": [
      { "source_url": "https://media.sume.com/artifacts/artf_demo/shot.mp4",
        "start": 0, "duration": 20, "fit": "cover" }
    ]
  }'

How do I add the subtitles Nextdoor recommends?

Video captions burns captions on a public HTTPS clip for $0.20 per video up to 60 seconds, which fits the under-30-second advice. Speech is required; a silent clip fails as caption_no_speech.

curl -X POST https://api.sume.com/v1/video-captions \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: nextdoor-captions-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/example/clean.mp4",
    "style": "black-outline",
    "language": "en"
  }'

How do I confirm the file before upload?

Probe the finished file with Video inspect 1.0. With frames: false it is a probe only, it is unbilled, and it reports width, height, container, fps and duration_seconds. It does not report file size, codec or bitrate, so check those with a local tool before you upload.

Nextdoor's limit is 500 MB, so a 20-second 1080p clip should sit well under it, but verify.

Does Sume handle the text fields?

No. Headline, body and CTA lengths are set in Nextdoor Ads Manager. Count characters against the table before you paste copy.