What was the rule state when you shipped? Signed.
Customs valuation, classification and origin disputes turn on what a party knew and when, relative to when a tariff or rule took effect. Months later, both sides argue from screenshots of a register and from an entry date nobody can pin down. This page returns one signed, independently re-verifiable record of the current US Federal Register rule state, and hands you a copy-curl to notarize the hash of the shipment, valuation or classification document at the same moment. Every reading is archived, so what the public rule feed said at time T stays re-checkable when the assessment lands later.
The public rule state, right now.
Fetch the current US Federal Register rule state, newest first, and Dynamic Feed returns one Ed25519-signed Decision Receipt produced by /v1/answer. Each entry carries the publication date that anchors a rule's effective timeline. Nothing is mocked and nothing is stored about you.
full signed receipt (JSON)
curl -X POST https://dynamicfeed.ai/v1/notarize -H "content-type: application/json" -H "X-API-Key: YOUR_FREE_KEY" -d '{"hash":"sha256:<your document hash>","ref":"customs-<entry-no>-valuation"}'
Hash the entry, invoice, valuation worksheet or classification memo in your own systems, then notarize the hash so its existence is fixed at this moment relative to the rule-state receipt above. Only the hash is sent, the document itself never leaves your systems. The returned record is Ed25519-signed with its key_id and is RFC 3161 timestampable against an accredited RFC 3161 authority. Re-verify any time against /.well-known/keys or with the MIT-licensed verifiers (see /verify). A free key is self-serve at POST /signup, details in the docs.
Customs disputes are decided on timelines.
When a valuation, classification or origin position is contested, the fight is rarely only about the tariff rate; it is about what the rule was and what the party knew, at the instant the shipment moved. Long after the fact, an entry date is disputed, a register screenshot is called selective, and an internal file timestamp is your own record on your own systems that the other side will say exactly that about. A contemporaneous record of the public rule state from an independent witness, signed at the moment and carrying its source and observation time, paired with a notarized hash of your own event document, is corroboration both sides can test. Our records work for importers, brokers and authorities alike: anyone can re-check them, and the archived reading for time T does not change when the assessment does.
Evidence, not a customs ruling.
Dynamic Feed is a neutral witness, not a customs authority, broker or adviser. The rule-state layer records the US Federal Register as published, so it does not interpret a tariff schedule, does not assign a classification, and does not determine an effective date, duty rate or origin. It is advisory evidence of what the public rule feed reported at that moment, and a notarized hash proves only that a document existed in that form then, not that its contents are correct. Laws, tariff schedules and contracts vary by jurisdiction and change over time, so the interpretation stays with your people. Dynamic Feed is one input beside the party's own entry records and the authority's ruling. Tamper-evident not more, zero personal data, and not legal advice.
One receipt per entry.
Trade and customs tooling can mint a signed rule-state receipt and notarize the entry document hash on every shipment automatically, keyless to try, self-serve to scale.