Read the Ledger at a Point in Time
Use the record-time and valid-time cursors to ask what was believed on one date about the world on another
Two cursors control a fold. Set either, both, or neither:
| Cursor | Parameter | Question it answers |
|---|---|---|
| Record time | recordedAt | What had the ledger recorded by then? |
| Valid time | validAt | Which claims hold in the world at that time? |
See what holds on a date
In the app, set Valid on in the ledger panel. Designations whose interval excludes that date move to Outside the valid interval; they are not deleted.
Through the API:
curl --get "https://api.y2.dev/api/v2/ledger/subjects/sbj_0123456789abcdef01234567" \
--header "Authorization: Bearer $Y2_API_KEY" \
--data-urlencode "validAt=2026-05-01T00:00:00Z"See what you believed before a correction
Set recordedAt to a time before the correction line was recorded. The fold uses only lines recorded
by then, so a claim you later retracted is still the head:
curl --get "https://api.y2.dev/api/v2/ledger/subjects/sbj_0123456789abcdef01234567" \
--header "Authorization: Bearer $Y2_API_KEY" \
--data-urlencode "recordedAt=2026-03-05T12:00:05Z"Combine both
"What did we believe on March 20 about April 10?" sets both:
curl --get "https://api.y2.dev/api/v2/ledger/subjects/sbj_0123456789abcdef01234567" \
--header "Authorization: Bearer $Y2_API_KEY" \
--data-urlencode "recordedAt=2026-03-20T00:00:00Z" \
--data-urlencode "validAt=2026-04-10T00:00:00Z"Record time selects a prefix of the log; valid time then filters the heads of that prefix. Valid time never walks back to an older version of a claim.
Export the same view
The STIX export takes the same cursors, so a partner receives exactly the picture you read:
curl --get "https://api.y2.dev/api/v2/ledger/subjects/sbj_0123456789abcdef01234567/stix" \
--header "Authorization: Bearer $Y2_API_KEY" \
--data-urlencode "recordedAt=2026-03-20T00:00:00Z" \
--data-urlencode "validAt=2026-04-10T00:00:00Z"Times accept any ISO 8601 instant; the ledger normalizes them to UTC milliseconds.