Interoperability
Connect agent payments, commerce mandates, card and bank rails, and external chains to Paxeer X through evidence-backed adapters.
One execution ledger, many entry points
Interoperability adapters translate foreign protocols into evidence that LayerX execution can verify. They preserve the original protocol's authorization and settlement facts while routing state changes through a receipt-verified LayerX operation. The 402LXP module remains the balance writer, and Paxeer X retains custody and withdrawal guarantees.
The interoperability gateway provides HTTP, MCP, and A2A ingress. Transport selects how a request arrives; the adapter selects how its evidence is validated. Applications keep the same operation identity and reconciliation process across these interfaces.
Connector catalogue
| Adapter | Application journey | Evidence boundary |
|---|---|---|
x402 | Buyer builds payment, seller offers a resource, facilitator verifies and settles | Payment evidence plus verified LayerX receipt; HTTP, MCP, and A2A transports |
ap2 | Verify an agent commerce mandate and execute within its authority | Verified mandate and LayerX receipt |
ucp | Complete a commerce checkout | Checkout evidence and receipt-gated execution |
visa-tap | Verify a trusted agent intent and execute its authorized action | Trusted agent credential, canonical target, and policy checks |
fiat | Process card, bank, and real-time-payment callbacks | External settlement evidence and LayerX receipt |
migration | Translate verified Ethereum or Solana source state into an import | Source-chain verification and migration rules |
Gateway discovery and operation tracking
GET /v1/adapters exposes adapter metadata. Track an operation with GET /v1/operations/{64-hex}, using its 64-hex operation identifier. The service also exposes GET /livez and GET /readyz for process and readiness checks. These are gateway paths relative to the configured gateway origin.
# Use the gateway origin assigned to your environment.
curl "$INTEROP_GATEWAY/v1/adapters"
curl "$INTEROP_GATEWAY/v1/operations/$OPERATION_ID"Build the request body from the selected adapter's schema. Preserve operation identifiers and evidence digests through retries. A successful HTTP exchange reports the gateway exchange; the operation's receipt-backed outcome establishes the state change.
Evidence policies
| Policy | Required basis |
|---|---|
layerx-receipt | A verified LayerX execution receipt |
verified-mandate+layerx-receipt | Accepted mandate authority and a verified execution receipt |
trusted-agent-credential | Agent credential accepted by the configured trust policy |
external-settlement+layerx-receipt | External rail settlement evidence paired with a verified execution receipt |
x402 over HTTP, MCP, and A2A
x402 supports buyer, seller, and facilitator roles. The same route family accepts http, mcp, or a2a as its transport segment. Capability discovery comes before constructing a payment, so clients can select the supported scheme and network.
| Method | Path | Purpose |
|---|---|---|
| GET | /v1/{transport}/x402/supported | Discover payment support |
| GET | /v1/{transport}/x402/facilitator/supported | Discover facilitator support |
| POST | /v1/{transport}/x402/buyer/build | Build buyer evidence |
| POST | /v1/{transport}/x402/seller/offer | Produce a seller offer |
| POST | /v1/{transport}/x402/verify | Verify payment evidence |
| POST | /v1/{transport}/x402/settle | Settle through LayerX execution |
Verification also has the /facilitator/verify variant; settlement has /seller/settle and /facilitator/settle variants beneath the same x402 prefix. Commitment extras and metered or subscription grant draws let applications bind payments to a resource and consume an authorized allowance over time.
Paid resource workflow
- The seller publishes an offer identifying the resource and payment terms.
- The buyer discovers support and builds evidence for the selected terms.
- The seller or facilitator verifies the evidence before accepting the purchase.
- Settlement submits the LayerX operation and verifies its receipt.
- The application associates resource delivery with the accepted payment operation and retains its evidence for reconciliation.
Agent commerce and fiat rails
| Method | HTTP route | Action |
|---|---|---|
| POST | /v1/http/ap2/mandates/verify | Verify mandate |
| POST | /v1/http/ap2/execute | Execute authorized mandate |
| POST | /v1/http/ucp/checkouts/complete | Complete checkout |
| POST | /v1/http/visa-tap/intents/verify | Verify trusted-agent intent |
| POST | /v1/http/visa-tap/intents/execute | Execute accepted intent |
| POST | /v1/http/fiat/card/callbacks | Accept card-rail evidence |
| POST | /v1/http/fiat/bank/callbacks | Accept bank-rail evidence |
| POST | /v1/http/fiat/rtp/callbacks | Accept real-time-payment evidence |
Mandate verification establishes what an agent may do before execution changes state. TAP policy binds the trusted agent and canonical request target, with clock-skew limits owned by the service. Fiat callbacks bind external settlement to the LayerX operation; repeating a provider notification must reconcile the original operation rather than credit it twice.
Portable receipts, mirrors, and migrations
Portable receipt verification checks LayerX evidence without requiring a live node connection. Ethereum and Solana mirrors publish batch archives and commitments so independent consumers can verify LayerX state. Mirrors carry verification data; custody remains on Paxeer X.
Migration adapters verify Ethereum or Solana source state for an import into LayerX. Choose migration for a source-state transition, a mirror for independent archive verification, and the bridge for a custody-backed asset transfer. Preserve the source chain identity and proof material in each case.
The stable node boundary
Adapters ultimately connect to LayerX through the LayerX Node Interface (LNI). LNI 1.7 uses length-prefixed frames over local Unix sockets, mutual-TLS TCP remotely, or a separately versioned C ABI. NodeInfo is the first exchange and supplies network identity, protocol version, chain head, finalised checkpoint, authorized sequencer, and capabilities.
Clients negotiate capabilities before submitting. Authenticated durable submission persists the admission record before acknowledgement. Receipt lookup, proof bundles, checkpoint reads, finality-evidence registration, account and asset reads, fee estimation, program reads, and program-head attestations support the complete adapter lifecycle. An admission acknowledgement precedes execution and publication; integrations retain those stages separately.
MCP integration choices
The agent MCP server routes tenant- and scope-bound calls through layerx-agentd. Interoperability MCP is the gateway ingress for foreign protocol requests. A2A is another ingress transport on the gateway and x402. Select the agent surface for managed agent tools and the interoperability surface for protocol translation.
Continue building
Explore bridging and custody, execution and settlement architecture, and native chain APIs to connect protocol evidence to chain state.