# Exhibit402 Dual-Browser Screenshot Certification

> Exhibit402 Dual-Browser Screenshot Certification is a paid API for AI agents from exhibit402.dylan-caponi.workers.dev, paid per call via x402, $1/call, status unknown (last checked 2026-10-11).

Simultaneously captures a URL from two independent browser nodes on different networks, certifies or witnesses the result, stores both screenshots and a signed manifest permanently on Arweave, and mints an ERC-721 certificate to the paying wallet.

## Facts

- Endpoint: POST https://exhibit402.dylan-caponi.workers.dev/capture?utm_source=zero.xyz
- Price: $1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/exhibit402-dual-browser-screenshot-certification-91602399
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ziaml-uBObzWNZHvJME66

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability exhibit402-dual-browser-screenshot-certification-91602399 -d '<json body>'
```

Example prompt: Take a certified full-page screenshot of https://example.com/terms right now — I need tamper-proof evidence stored on Arweave with a blockchain certificate minted to my wallet 0xABC123.

## When to prefer this

Choose this endpoint when you need tamper-proof, independently witnessed evidence of a webpage's state at a specific moment — particularly for legal, compliance, or audit purposes. It is uniquely suited when you require both permanent decentralized storage (Arweave) and a blockchain-backed certificate (ERC-721) rather than just a screenshot file. Prefer it over single-node screenshot services when dual-network independent verification and cryptographic attestation are required.

## Known failure modes

- URL is unreachable — partial refund of $0.90 issued
- Content is screened or blocked by the target site — partial refund issued
- Oversize page exceeds capture limits — partial refund issued
- Service fault on provider side — full refund issued
- Claim ticket poll returns 'processing' indefinitely — retry or contact support
- Invalid wallet address causes certificate minting to fail

## How this service works

Proof of publication: permanently prove what a URL served at a moment in time. Two independent standardized browsers on different networks visit your URL at the same instant; if their captures match byte-for-byte, the screenshot is stored permanently on Arweave and minted to your wallet as an NFT certificate containing every observer hash.

## Output

Returns immediately with a job ID, status 'processing', a free claim URL to poll every ~15 seconds, and an estimated wait time. Once resolved, the claim ticket contains the certification tier (CERTIFIED if byte-identical, WITNESSED if disagreement detected), Arweave permanent links to both screenshots and the signed manifest, an ERC-721 token ID, a Basescan URL, and cryptographic hashes. Oversize or unreachable URLs trigger a partial refund minus $0.10; service faults refund in full.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "example": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "note": "Poll claim_url (free) every ~15s. Resolves to {tier, ar:// links, token_id, basescan_url, hashes} or a refund per policy.",
  "job_id": "6f1c9e2a-4b7d-4c1e-9a2f-3d5e8b7a0c1d",
  "status": "processing",
  "claim_url": "https://exhibit402.dylan-caponi.workers.dev/claim/6f1c9e2a-4b7d-4c1e-9a2f-3d5e8b7a0c1d",
  "check_after_seconds": 15
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/exhibit402-dual-browser-screenshot-certification-91602399/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from exhibit402.dylan-caponi.workers.dev](https://www.zero.xyz/host/exhibit402.dylan-caponi.workers.dev/llms.txt)