CAST is a bilateral coordination protocol for commercial payments. Before a covered payment moves, both parties co-author one cryptographically bound record of the intended transaction — who is paying, who is receiving, how much, and where it goes — through a channel bound to a verified identity. That co-authored record is the authorization. It is signed, timestamped, policy-versioned, and tamper-evident. It travels with the payment through every downstream system without requiring reconstruction.Documentation Index
Fetch the complete documentation index at: https://docs.cast.digitalfinancehq.com/llms.txt
Use this file to discover all available pages before exploring further.
The one-line thesis. The proof is produced once, at transaction time. Verification cost drops to near zero, because checking a hash is structurally cheaper than reconstructing a decision chain.
Why CAST exists
Most payment controls assume that an instruction originating inside the organization — from a known email, an approved user, a familiar vendor record — is trustworthy. That assumption is the gap. A payment process where only one of two parties has confirmed the terms before value transfers is not a bilateral authorization. It is a unilateral instruction with a hope attached. The counterparty learns of the transaction only when money arrives, when it does not arrive, or when something is already wrong. CAST adds one narrow control: before a covered payment is released, the counterparty confirms the payment details through a secure, cryptographically bound channel.The economic moment
As AI commoditizes execution — the cost of generating financial output approaches zero — the binding constraint in the economy shifts from production to verification. The question stops being can we produce this output and becomes can we prove this output is trustworthy. CAST expands the verifiable share of economic activity by replacing opinion-based reconstruction (an auditor reading email threads) with proof-based verification (a lineage-hash check anyone can run). The proof asset is produced once. The subscription fee is the cost of producing it.Read the economic argument in full
How value accrues to whoever can verifiably underwrite the output — the Catalini thesis applied to commercial payments.
Where to go next
CAST in 5 minutes
The mental model: Event → Policy → Work Order → Posting, with lineage binding it all.
What CAST is not
The boundaries we draw on purpose — and why honesty about them is an asset.