Measured. Reproducible. Explicit about limits.

Every number on this page is copied by hand from a real artifact produced by our own validation harnesses — real TCP/HTTP against a real gateway process and a real durable state store, never in-process function calls or invented figures. Reviewed 2026-09-11.

Validation scale

The attempted-request scale of each real adversarial or concurrency workload, log-scaled because these scenarios legitimately span 1,000 to 1,000,000 attempts.

Correctness outcomes

Each row is one real run: what was attempted, what was accepted, what was rejected, and the invariant checked against database state — not only the test harness's own counters.

TestCategoryStatusAttemptedAccepted / RejectedInvariant
Multi-Tenant IsolationSecurity CorrectnessPASS1,000,0000 / 1,000,0000 cross-scope budget influence, 0 cross-scope approval consumption, 0 unexpected 5xx
Replay ProtectionSecurity CorrectnessPASS1,000,0000 / 1,000,0000 duplicate replay acceptances, 0 budget violations
Budget Race (single reservation, concurrent claims)ConcurrencyPASS100,0001 / 99,999exactly 1 successful consumption, 0 double-consumes, 0 budget violations
Approval Consumption Race (cross-replica)Distributed SystemsPASS2002 / 1981 successful consumption per repeat, 0 duplicate_successful_consume, final SQL state = consumed
Multi-Replica Identity (restart + concurrency sweep)Distributed SystemsPASS500500 / 00 id_collisions, 0 false_idempotent_alias at concurrency 100/500/1000; DB row count matches harness (2,100 = 2,100)
Trust-Boundary ClosureSecurity CorrectnessPASS5252 / 052 / 52 real, separate-OS-process boundary assertions pass
Broker Failure RecoveryFailure RecoveryIN PROGRESS00 / 0results publish on completion

Environment & methodology

Every result above states its own topology, state backend and transport — none are shared assumptions.

Multi-Tenant Isolation

1,000,000 requests from tenant B attempting to influence or read tenant A's budget/approval state, real HTTP path end to end.

Topology2 adversarial tenant scopes against 1 gateway replica
Stateshared durable state store
Transportreal TCP/HTTP, 127.0.0.1 loopback
Concurrency200
Replicas1

Replay Protection

1,000,000 replayed payment-proof requests against the real enforcement path.

Topology1 gateway replica
Stateshared durable state store
Transportreal TCP/HTTP
Concurrency200
Replicas1

Budget Race (single reservation, concurrent claims)

100,000 concurrent requests racing to consume the same single budget reservation.

Topology1 gateway replica
Stateshared durable state store
Transportreal TCP/HTTP
Concurrency200
Replicas1

Approval Consumption Race (cross-replica)

Two repeats of a 100-way concurrent burst racing to resume the same approval grant across 4 replicas.

Topology4 gateway replicas
Stateshared durable state store
Transportreal TCP/HTTP
Concurrency100
Replicas4

Multi-Replica Identity (restart + concurrency sweep)

10 restart cycles x 50 distinct legitimate requests, re-run at 3 concurrency levels.

Topology10 restart cycles, same scope, concurrency swept 100 -> 500 -> 1,000
Stateshared durable state store
Transportreal TCP/HTTP
Replicas2

Trust-Boundary Closure

Structural checks that the issuer's DB role cannot write authorization_records, the gateway config contains no signing key, least-privilege roles start and serve real traffic, and related isolation invariants.

Topologyauthorization issuer + external payment signer + gateway as 3 distinct OS processes
Statedurable state store with least-privilege roles per process
Transportreal process boundaries, real DB role grants

Broker Failure Recovery

Broker outage/recovery drill while the gateway continues serving live traffic.

Topologyreal JetStream broker stop/start under continuous live gateway traffic
Stateshared durable state store
Transportreal TCP/HTTP

Not yet complete -- shown as IN PROGRESS, not fabricated as PASS.

Test suite

cargo test --workspace --all-features593 passed, 0 failed, 2 ignored. Verified 2026-09-11. This single constant is the only place this number is defined — every page that shows it reads from here.

Protocol status

Direct x402TESTNET VERIFIED
A2A + x402TESTNET VERIFIED
AADP (delegated payment)TESTNET VERIFIED
MPPREFERENCE INTEROPERABLE

Where x402Shield fits

A feature comparison against publicly documented capabilities of adjacent agent-payment and wallet-infrastructure products. x402Shield does not win every row — see the honestly-marked gaps below.

Based on publicly documented capabilities. Reviewed September 2026. Feature/capability comparison only — no performance claims are made about any vendor without an equivalent, publicly documented benchmark methodology.

Authorization infrastructure landscape comparison across 6 vendors and 14 dimensions
Dimensionx402ShieldPayment authorization boundaryCrossmintAgent-payment platformTurnkeyWallet + signing policy infrastructureAWS Bedrock AgentCore PolicyGeneral agent-action authorizationSkyfireAgent-payment platformCoinbase x402 / CDP FacilitatorPayment protocol / facilitator
Primary roleWhat the product is built to do firstYesYesPartial / different modelYesYesYes
Built specifically for agent paymentsvs. a general product agent payments is one use case ofYesYesPartial / different modelPartial / different modelYesPartial / different model
Customer-defined spending controlsLimits, caps, allowlists the customer configuresYesYesYesPartial / different modelYesNot publicly documented
Deterministic authorizationSame request always yields the same decision, no model in the decision pathYesPartial / different modelYesYesNot publicly documentedNot publicly documented
Human approval supportA person can be required to approve a specific actionYesYesYesPartial / different modelNot publicly documentedNot publicly documented
x402 supportSpeaks the x402 HTTP payment protocolYesYesNot publicly documentedNot publicly documentedNot publicly documentedYes
Wallet / signing infrastructureHolds or produces the signing key itselfNot publicly documentedYesYesNot publicly documentedYesNot publicly documented
Can sit in front of customer-controlled signing infraAuthorizes without requiring custody of the keyYesNot publicly documentedNot publicly documentedNot publicly documentedNot publicly documentedNot publicly documented
Exact request ↔ payment authorization bindingThe signed payment is cryptographically bound to the exact authorized requestYesNot publicly documentedNot publicly documentedPartial / different modelNot publicly documentedPartial / different model
Separate authorization vs. payment-signing boundaryThe thing that decides is a different process/key than the thing that signsYesNot publicly documentedPartial / different modelNot publicly documentedNot publicly documentedNot publicly documented
Delegated financial authority / attenuationA parent can grant a narrower, never-wider authority to a sub-agentYesNot publicly documentedPartial / different modelNot publicly documentedNot publicly documentedNot publicly documented
Replay / idempotency protectionA repeated request cannot execute twiceYesNot publicly documentedNot publicly documentedNot publicly documentedNot publicly documentedPartial / different model
Authorization evidence / reconciliationA durable, checkable record of what was authorized and signedYesNot publicly documentedNot publicly documentedYesPartial / different modelNot publicly documented
Payment settlementActually moves/confirms funds on a railNot publicly documentedYesYesNot publicly documentedYesYes
x402ShieldPayment authorization boundary

Payment-specific authorization boundary between agent intent and signing infrastructure

Primary role
Yes
Built specifically for agent payments
Yes
Customer-defined spending controls
Yes
Deterministic authorization
Yes
Human approval support
Yes
x402 support
Yes
Wallet / signing infrastructure
Not publicly documented
Can sit in front of customer-controlled signing infra
Yes
Exact request ↔ payment authorization binding
Yes
Separate authorization vs. payment-signing boundary
Yes
Delegated financial authority / attenuation
Yes
Replay / idempotency protection
Yes
Authorization evidence / reconciliation
Yes
Payment settlement
Not publicly documented
CrossmintAgent-payment platform

Agent payment platform — non-custodial wallets, cards and stablecoin payments for agents

Primary role
Yes
Built specifically for agent payments
Yes
Customer-defined spending controls
Yes
Deterministic authorization
Partial / different model
Human approval support
Yes
x402 support
Yes
Wallet / signing infrastructure
Yes
Can sit in front of customer-controlled signing infra
Not publicly documented
Exact request ↔ payment authorization binding
Not publicly documented
Separate authorization vs. payment-signing boundary
Not publicly documented
Delegated financial authority / attenuation
Not publicly documented
Replay / idempotency protection
Not publicly documented
Authorization evidence / reconciliation
Not publicly documented
Payment settlement
Yes
TurnkeyWallet + signing policy infrastructure

Wallet and signing infrastructure with a policy engine enforced inside a secure enclave

Primary role
Partial / different model
Built specifically for agent payments
Partial / different model
Customer-defined spending controls
Yes
Deterministic authorization
Yes
Human approval support
Yes
x402 support
Not publicly documented
Wallet / signing infrastructure
Yes
Can sit in front of customer-controlled signing infra
Not publicly documented
Exact request ↔ payment authorization binding
Not publicly documented
Separate authorization vs. payment-signing boundary
Partial / different model
Delegated financial authority / attenuation
Partial / different model
Replay / idempotency protection
Not publicly documented
Authorization evidence / reconciliation
Not publicly documented
Payment settlement
Yes
AWS Bedrock AgentCore PolicyGeneral agent-action authorization

General-purpose, deterministic tool-call authorization for AI agents

Primary role
Yes
Built specifically for agent payments
Partial / different model
Customer-defined spending controls
Partial / different model
Deterministic authorization
Yes
Human approval support
Partial / different model
x402 support
Not publicly documented
Wallet / signing infrastructure
Not publicly documented
Can sit in front of customer-controlled signing infra
Not publicly documented
Exact request ↔ payment authorization binding
Partial / different model
Separate authorization vs. payment-signing boundary
Not publicly documented
Delegated financial authority / attenuation
Not publicly documented
Replay / idempotency protection
Not publicly documented
Authorization evidence / reconciliation
Yes
Payment settlement
Not publicly documented
SkyfireAgent-payment platform

Agent payment network — agent wallets, identity (KYA) and per-agent spending limits

Primary role
Yes
Built specifically for agent payments
Yes
Customer-defined spending controls
Yes
Deterministic authorization
Not publicly documented
Human approval support
Not publicly documented
x402 support
Not publicly documented
Wallet / signing infrastructure
Yes
Can sit in front of customer-controlled signing infra
Not publicly documented
Exact request ↔ payment authorization binding
Not publicly documented
Separate authorization vs. payment-signing boundary
Not publicly documented
Delegated financial authority / attenuation
Not publicly documented
Replay / idempotency protection
Not publicly documented
Authorization evidence / reconciliation
Partial / different model
Payment settlement
Yes
Coinbase x402 / CDP FacilitatorPayment protocol / facilitator

x402 payment protocol reference facilitator — payment verification and on-chain settlement

Primary role
Yes
Built specifically for agent payments
Partial / different model
Customer-defined spending controls
Not publicly documented
Deterministic authorization
Not publicly documented
Human approval support
Not publicly documented
x402 support
Yes
Wallet / signing infrastructure
Not publicly documented
Can sit in front of customer-controlled signing infra
Not publicly documented
Exact request ↔ payment authorization binding
Partial / different model
Separate authorization vs. payment-signing boundary
Not publicly documented
Delegated financial authority / attenuation
Not publicly documented
Replay / idempotency protection
Partial / different model
Authorization evidence / reconciliation
Not publicly documented
Payment settlement
Yes

Known limitations

  • Settlement is observed as server-reported evidence only in the current build; it is never conflated with on-chain confirmation, and the evidence layer labels it as such.
  • Delegation trust is anchored at the root of a presented chain via a configured HMAC trust anchor; intermediate hops are validated structurally and can never exceed the signed root ceiling.
  • Broker failure-recovery validation under sustained live traffic is still in progress.
  • Published throughput and concurrency figures are controlled test-environment results, not a production capacity guarantee or SLA.
  • No instrumentation-overhead A/B baseline exists yet -- the current build always compiles metrics in, so there is no toggle to measure true overhead against a bare build.

Security model & trust boundaries →