Avyth

For youtube creators

The two checks before you press publish.

One tool for the thumbnail and one for the sound. Both run on your device, both show you what the viewer gets rather than a score, and neither needs an extension or your channel login.

Open Thumbnail PreflightAll fourteen tools →

The week, in order

  1. 1 · The thumbnail is done

    Thumbnail Preflight

    What it does →

    Shows the thumbnail and title at true pixel size on the phone feed, desktop home, the suggested sidebar and search, in light and dark, with YouTube's duration badge, buttons and progress bar drawn where they land — and the 168-pixel render so you can see whether the text survives.

    The whole tool is free; nothing is behind a key.

  2. 2 · The edit is exported

    Playback Check

    What it does →

    Decodes the video's audio in your browser and plays it back through seven modelled devices — phone speaker, laptop speakers, a TV's built-in speakers, a soundbar, earbuds, over-ear headphones and a car — with its loudness, true peak and range measured against YouTube's −14 LUFS normalisation, and a named fix for each problem.

    The first three minutes of any file, all seven devices, every number and suggestion, free; the subscription measures the whole file.

What it costs

Thumbnail Preflight is free. Playback Check is $5 a month on its own or in the $8 Creator bundle with Substack Archiver; every paid tool is $24.

What this page won't pretend

  • Predicting clicks. Thumbnail Preflight shows the render; YouTube Studio's Test & Compare runs the real experiment on real viewers.
  • Fixing the audio for you. Playback Check names the number and how to change it in your editor; you listen, then decide.
  • Exact device measurements. The seven devices are models of typical hardware, and the page says so.

Questions

Is my video uploaded?
No. The file is decoded by your browser's own audio decoder and every measurement runs on your device. Some codecs inside video containers cannot be decoded in a browser; the tool says so and asks for the exported audio track instead.
Why does YouTube turn my video down?
YouTube normalises playback to about −14 LUFS. A louder video is turned down by the difference, quiet parts included. Playback Check shows the difference so you can master to it rather than discover it after upload.
Are the thumbnail sizes exact?
They are YouTube's web and mobile layouts as measured in September 2026, updated when they change. The typeface is the page's, not Roboto, so a title may truncate a character earlier or later than on YouTube.
Do I need an account?
Not for Thumbnail Preflight or the free three minutes of Playback Check. The subscription uses an Avyth account so the same $5 unlocks the tool on every device you use.

Other kinds of workCompared with what you might use instead