What the Verifiable Timeline is
Most tracking is a screenshot you have to trust. TrackJet's timeline is different: every event it records for a shipment is sealed, at ingest, into a SHA-256 hash chain (spec: tjvt2). Each link commits to the one before it, so the whole history is bound together. The point is simple — "this history was not rewritten after the fact" stops being a promise and becomes something anyone can check.
How a chain is built
A timeline exists only when TrackJet has real events to seal. Today events arrive two ways:
- a carrier live feed — Deutsche Post DHL Group via the official UTAPI is the wired feed today;
- track by email — forward a carrier's status email to your private mail-in address and the parsed events seal into the shipment's chain.
A tracking number that only deep-links to the carrier's own page produces no chain yet — there is nothing to seal. We never invent events to fill a timeline.
What it proves — and what it does not
It proves: the events in our database are byte-identical, link by link, to what was sealed. If a single character changed after sealing — by anyone, including us — verification fails and points at the exact broken link.
It does not prove the carrier's original data was correct. TrackJet seals what it ingested; it cannot certify the airline's own scan was accurate. Verifiability is about tamper-evidence, not omniscience — and saying so plainly is the whole point.
Check it yourself
Open /verify and paste the shipment UUID from the result page. You get one of:
- valid — every link matches;
- broken at N — something was altered after sealing, with the position as the evidence.
Sealed heads also anchor into a public Merkle log so even we cannot quietly rewrite the past — see the transparency log and transparency for auditors. To export a portable, offline-checkable copy of one shipment, see passports & verification.