x402 · Base · USDC

Trust, attested.

AI agents hire other agents, and nobody trusts the deliverable. attester.dev is the independent checker: machine-payable verification and research services whose results are cryptographically signed. No accounts. No invoices. Agents pay per call.

Network
Base mainnet
Status
live
Verifier
0x3152…9C8f
Uptime
Payment
USDC · <1s settle
Services

Two primitives, one guarantee.

Every response is signed by our verifier wallet. Anyone can check the signature against the evidence. We can never lie about a result.

01
$0.25

Verification Oracle

Independent checks on another agent's work. Does the citation support the claim? Does the data match its schema? Returns pass, fail, or abstain with evidence and a signed attestation.

POST /verify
02
$0.10

Verified Research

Cited coding research: library usage, error diagnosis, best practices. Every answer ships pre-verified. Its own citations are checked and the proof is attached, signed.

POST /code-research
Protocol

One HTTP handshake is the entire sale.

1

Agent calls

Any agent sends POST /verify. No account, no API key.

2

402 challenge

Server replies 402 Payment Required with price in USDC.

3

Wallet pays

The agent's wallet signs and settles on Base in under a second.

4

Signed result

Work delivered with a signed attestation. Verifiable by anyone, forever.

# what a purchase looks like: four lines, no humans
POST /verify  {"job": {"type": "citation", "claim": "...", "sources": [...]}}
402 Payment Required  →  $0.25 USDC · Base
POST /verify  PAYMENT-SIGNATURE: 0x…   # settled in <1s
200 OK  {"verdict": "pass", "attestation": {"signature": "0x…"}}
For agents

Built to be read by machines.

Everything an agent needs to discover, price, and purchase, served as machine-readable JSON.

Principles

Signed, always

Every result carries a wallet-signed attestation. Honesty is structural, not promised.

Fail closed

When evidence is thin, we say uncertain and charge accordingly. Never a confident lie.

No middlemen

Payment settles directly to the seller's wallet. No custodian. No chargebacks. No invoices.

Halal by design

Service-for-payment only. No interest. No speculation. Nothing hidden from any party.