vidpickr

Glossary · concept

What is Signed URL?

A signed URL is a download link with cryptographic parameters that authenticate the request and expire after a set time. YouTube's video stream URLs are signed and typically expire in ~6 hours. After expiry the URL returns 403 even if the video is still public.

Also called:signed link · expiring url · token-signed url

Signed URLs let a service like YouTube hand out direct CDN links without anyone being able to permanently mirror them. Each link contains an expiration timestamp, the requesting client's IP, and a cryptographic signature derived from those plus a server-side secret. Any tampering breaks the signature; the link is rejected.

For YouTube downloaders, signed URLs are why you can't share a download link with a friend — the IP lock makes it work only from the IP that requested it. They're also why a "save" button that worked an hour ago might silently fail later — the URL has expired.

VidPickr re-mints download tokens on every page open and refreshes them on long-open tabs, so the URLs you click on always have a full validity window ahead of them. The signed URLs themselves come from YouTube's CDN; we never modify them.

Common questions

Why does my YouTube download link expire?
YouTube signs every video URL with a 6-hour expiry. The signature includes your IP and the timestamp; once the timestamp passes, the URL returns 403.
Can I extend a signed URL's expiry?
No — the signature is server-side. The only way to "extend" is to request a fresh signed URL via a fresh extraction.

Related terms

Range request (HTTP byte range)

A range request is an HTTP request that asks for a specific byte range of a file rather than the full thing.

Manifest (streaming)

A manifest is a small text file that lists every segment of a streaming video, plus available qualities, codecs, and timing.

VidPickr is a free, browser-based YouTube downloader. Every term in this glossary either describes how YouTube delivers video or why your downloads behave the way they do. Try the downloader →