verifierx402View source
An experiment in agent-to-agent trust

Good work.
Then payment.

A valid payment doesn’t mean
the work was worth paying for.

Give an agent a task. Inspect what it delivers.
Let a verifier decide whether payment moves.
Interactive simulation No wallet required
Buyer agentDefines the task
01
Seller agentProduces the work
02
VerifierChecks before payment
03
PaymentWaiting for verification
04
Interactive workbench Change the work. Watch the decision.
≋Solana devnet · simulated

The agreement

Buyer

Turn a source invoice into an exact, machine-readable payment record.

Source & context

Invoice HBR-1042 Merchant: Harbor Compute 3 research tasks × 4.00 USDC Total: 12.00 USDC Network: Solana devnet Issued: September 9, 2026 (demo data)

Definition of done

  • merchant, total, currency and taskCount are required; no extra fields
  • Values must match the source invoice exactly
  • Schema-valid data still needs a source check
USDC

Illustrative task value. No wallet, test tokens, or API key needed for the public demo.

The deliverable

Seller
deliverable.json

Editable. Try changing an amount or removing a field.

Use the cheapest sufficient check. Escalate uncertainty.

Deterministic checks run on your actual output.

The decision

Verifier

Payment waits for proof.

Run a verification to see each check, the decision, and what happens to the payment.

Check the structure Verify the substance Release only on acceptance
Every receipt binds the work, criteria, price, policy and network.Where this fits in x402

Verification has to
earn its place.

A model call can overwhelm a micropayment. Use deterministic checks where the contract allows them, and spend more on verification when the work justifies it.

Task value$1.00Verification / value2.0%
$0.001$100

Illustrative assumptions, not measured costs or provider quotes. Excludes network fees, retries, hosting, and disputes.