ARCS/Crosswalks/ARCS / x402 Crosswalk
ARCS / x402
Overview
x402 is an open protocol for internet-native payments built around the HTTP 402 status code. It supports payment-gated access to APIs and digital resources. In V2, the protocol also introduces wallet-based identity, reusable sessions, discovery metadata, extensible payment schemes, and support across multiple payment networks and settlement environments. Its transaction architecture commonly involves clients, resource servers, facilitators, and chain-adjacent settlement surfaces.
ARCS is a lifecycle-governance standard for records created by automated systems. The relevant question is whether x402-mediated payment activity yields retained artifacts such as payment requests, signatures, settlement receipts, facilitator verification records, or downstream access records.
Interpretive status
This instrument is an informative protocol crosswalk. It does not establish normative equivalence between x402 and ARCS and does not restate the x402 specification. x402 specifies payment execution behavior. ARCS governs record lifecycle and custody once transaction artifacts persist.
Protocol scope
x402 specifies how payment requirements are declared through HTTP responses, how clients authorize payment payloads, how facilitators verify and settle transactions, how settlement confirmation is returned, and, in V2, how discovery metadata and wallet-linked session patterns can support repeated access. It does not specify retention, custody, deletion posture, preservation triggers, or compelled-production treatment for the resulting artifacts.
ARCS relevance
ARCS becomes relevant when x402 transactions produce retained artifacts: payment requests, signatures, verification outputs, settlement confirmations, transaction logs, and access records generated by payment-gated resource delivery. Where x402 is used in agent-initiated payment flows, the resulting traces become a governed record class.
Selected mappings
Table A maps selected x402 protocol surfaces to ARCS control families. The table is interpretive. It does not assert one-to-one correspondence between x402 protocol requirements and ARCS controls. It identifies the record-lifecycle questions that arise when payment execution artifacts persist.
| x402 protocol surface | Spec reference | ARCS families | Crosswalk note |
|---|---|---|---|
| Payment request and 402 response | HTTP 402 flow | ARCS-LIF, ARCS-TAX, ARCS-CUS | x402 specifies how servers declare payment requirements through HTTP 402 responses. ARCS governs lifecycle and custody treatment for payment request artifacts, response metadata, and transaction logs once those materials persist beyond the request-response exchange. |
| Payment verification and settlement | Facilitator /verify, /settle | ARCS-VER, ARCS-CUS, ARCS-LIF | x402 specifies facilitator verification and settlement behavior. ARCS governs custody, retention, and verification treatment for settlement artifacts, receipts, and related transaction records across operator, facilitator, and chain-adjacent surfaces. |
| Client payment signature | PAYMENT-SIGNATURE header | ARCS-TAX, ARCS-LIF, ARCS-PUB | x402 specifies how clients sign and submit payment authorization. ARCS governs classification, retention, and disclosure treatment for signed authorization artifacts once retained, exported, or reviewed outside the transaction path. |
| Settlement response and receipt | PAYMENT-RESPONSE header | ARCS-LIF, ARCS-VER, ARCS-CUS | x402 returns settlement confirmation through protocol response materials. ARCS governs retention, custody, verification status, and evidentiary treatment for those retained artifacts. |
| Agent-to-agent and M2M payments | Agentic payment flows | ARCS-AGT, ARCS-DEL, ARCS-CUS | x402 supports autonomous payment flows. ARCS governs retained artifacts arising from agent-initiated transactions, including tool traces, delegation records, authorization materials, and downstream transaction records. |
| Resource server and API monetization | Server middleware | ARCS-OPB, ARCS-CUS, ARCS-PUB | x402 specifies payment-gated resource access. ARCS governs operator-boundary, custody, and disclosure treatment for transaction records and payment-linked access records once those materials cross organizational or vendor boundaries. |
| Payment schemes and extensibility | Scheme specifications | ARCS-TAX, ARCS-LIF | x402 supports extensible payment schemes, including exact, metered, and streaming flows. ARCS governs classification and lifecycle treatment for the records produced under each scheme once retained. |
| Facilitator as independent custodian | Facilitator architecture | ARCS-CUS, ARCS-OPB, ARCS-VER | x402 facilitators are third-party intermediaries that verify and settle payments independently of both client and resource server. Each facilitator retains its own operational records of verification decisions, settlement broadcasts, and transaction metadata under its own retention posture. ARCS requires custody chain documentation at each custodian, including facilitators, with mapped possession, control, access, and deletion authority. |
| On-chain settlement records | Blockchain settlement | ARCS-LIF, ARCS-CUS, ARCS-PUB | x402 payment execution commonly results in on-chain settlement records that are architecturally non-deletable. This creates a distinct custody condition: lifecycle controls such as deletion and expiration cannot be applied to the settlement layer. ARCS requires that architecturally precluded deletion be documented and that disclosure posture account for the permanent reachability of on-chain artifacts. |
| Discovery and service metadata | Discovery extension (V2) | ARCS-TAX, ARCS-CUS, ARCS-PUB | x402 V2 supports discovery metadata that facilitators can crawl and index. ARCS governs classification, custody, and disclosure treatment for indexed endpoint metadata, search activity, routing records, and related discovery artifacts once retained. |
| Wallet-based identity and reusable sessions | Wallet-linked access / reusable sessions (V2) | ARCS-DEL, ARCS-CUS, ARCS-LIF | x402 V2 introduces wallet-linked access patterns that allow repeated access without repeating full payment flows. ARCS governs lifecycle, custody, and delegation-related treatment for persistent identity bindings, reusable access records, and cross-session transaction context. |
Outside scope
x402 is a payment execution protocol. It does not specify the record-lifecycle domains listed below.
Non-creation claim verification
ARCS-NCR (NCR-01 to NCR-06)
x402 does not specify how claims of non-creation or non-retention are established. Where an operator asserts that payment interactions do not yield governed records, ARCS requires architectural verification of that assertion.
Deletion verifiability for transaction records
ARCS-LIF (LIF-12, LIF-13), ARCS-VER (VER-01 to VER-03)
x402 does not govern deletion of payment records after settlement. ARCS requires deletion claims for transaction artifacts to be verifiable and requires architecturally precluded deletion, including common chain-linked conditions, to be documented.
Preservation and legal hold
ARCS-PV (PV-01 to PV-07)
x402 does not define preservation triggers. When payment-linked records become subject to legal, regulatory, or investigative hold, ARCS governs suspension of deletion and coordinated preservation across distributed surfaces.
Multi-vendor custody chain mapping
ARCS-CUS (CUS-01 to CUS-12)
x402 transactions may involve clients, resource servers, facilitators, and blockchain networks. ARCS requires documentation of possession, control, access, and deletion authority at each custodian in the resulting record chain.
Cross-session memory and persistent payment context
ARCS-DEL (DEL-01 to DEL-12)
x402 does not specify lifecycle treatment for payment history, preferences, or authorization patterns that persist across sessions. V2 introduces wallet-based identity and reusable sessions that create persistent identity bindings across multiple transactions. Under ARCS, those artifacts are subject to classification, custody, and retention treatment once retained.
On-chain immutability and lifecycle constraint documentation
ARCS-LIF (LIF-12, LIF-13), ARCS-CUS (CUS-07, CUS-08)
x402 settlement records are written to blockchain networks where deletion is architecturally precluded. This is a structurally distinct custody condition from protocols where records are operationally retained but technically deletable. ARCS requires that non-deletable record surfaces be documented, that disclosure posture account for permanent reachability, and that the distinction between off-chain artifacts (deletable) and on-chain artifacts (non-deletable) within the same transaction be mapped.