Per-Torrent Trackers

Add or remove tracker URLs on a running torrent from the inspector's Trackers tab.

The tracker list on a .torrent (or magnet, once metadata resolves) isn’t always what you want. Maybe the original tracker is dead and you want to point at a live one; maybe you added a magnet that has no tracker tier and you want to seed it through your own. The Trackers tab in the inspector lets you edit the announce list in place — both additions and removals — and persists the user-added trackers across restarts.

Where to find it

Inspector → Trackers tab. Existing trackers appear with their status badge (OK / Updating / Error); user-added trackers are interleaved with the metainfo’s original announce list.

  • Add: type or paste a URL in the input at the bottom (http://, https://, or udp://) and click Add (or press Enter). The new tracker is announced to immediately.
  • Remove: hover any tracker row and click the small trash icon that appears on the right.

User-added trackers persist in the torrent_trackers table and are re-applied on startup, so a tracker you added yesterday is still there after a restart. Removing a tracker that came from the original metainfo persists too — Mosaic remembers your removal and doesn’t re-add it on the next session.

How removal works

anacrolix v1.61 exposes ModifyTrackers, which atomically stops all announcer goroutines and replaces the announce list. Mosaic reconstructs the desired list (every tier from the metainfo, minus the URL you removed, plus your additions) and passes it as a single replacement. The legacy single-Announce field is folded into the first tier if present.

Caveats

  • No tier editing. The UI presents a flat list. Mosaic preserves tier ordering from the metainfo but doesn’t let you reorder or split tiers. If you need fine-grained tier control, edit the .torrent before adding it.
  • No URL validation beyond the engine’s own check. anacrolix accepts what looks like a valid URL; bad URLs surface as Error: … in the status badge once the first announce fails. Look at the row badge to confirm a new tracker is healthy.
  • Private trackers don’t accept arbitrary additions. If you’re on a private tracker that pins peer announces to its own URL, adding a public tracker to a private torrent does nothing useful and may violate the tracker’s rules.
  • Tracker stats are per-tracker. “Last announce” timestamps and peer/seed counts are reported by the tracker itself; some trackers send zero or stale numbers regardless of what’s actually happening.

API

POST   /api/torrents/{infohash}/trackers   body: { "url": "..." }
DELETE /api/torrents/{infohash}/trackers   body: { "url": "..." }

DELETE with a body is unusual but is the chosen shape here — the URL has to travel somewhere, and putting it in the path would require percent-encoding ://. See REST Endpoints → Torrents.

See also