C2PA Verify

Agent-native C2PA manifest verification API. Upload an image (or URL), get back a cryptographically-validated provenance manifest. Pay per call — no accounts, no subscriptions.

• Endpoint: https://c2pa.mppfy.com/verify
• Price: $0.01 USDC per call
• Protocols: x402 (Base mainnet) · MPP (Tempo mainnet)
• Discovery: /openapi.json · /llms.txt · PayAI Bazaar

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Who this is for

• Agents that download media from the open web and need to know: is this AI-generated, edited, or authentic?
• Content pipelines that ingest third-party images/video and must preserve provenance (newsrooms, stock platforms, moderation).
• Developers prototyping C2PA integrations who don't want to embed a 15MB Rust/WASM verifier in every service.

The C2PA standard (c2pa.org, adopted by Adobe, Microsoft, BBC, Sony, Truepic, OpenAI) embeds signed provenance metadata in images. Parsing + validating the signature chain against the Content Authenticity Initiative trust list normally requires c2pa-rs / c2pa-node and the current trust anchors. This service offloads that to one HTTP call.

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Quick start

Option A — pay with x402 (Base USDC)

Works with any x402 client SDK:

import { createWalletClient, http } from 'viem';
import { base } from 'viem/chains';
import { privateKeyToAccount } from 'viem/accounts';
import { wrapFetchWithPayment } from 'x402-fetch';

const wallet = createWalletClient({
  account: privateKeyToAccount(process.env.WALLET_PK as `0x${string}`),
  chain: base,
  transport: http(),
});

const pay = wrapFetchWithPayment(fetch, wallet);

const r = await pay('https://c2pa.mppfy.com/verify', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ url: 'https://example.com/signed-image.jpg' }),
});

console.log(await r.json());

Or manually — trigger the 402 challenge and inspect the requirements:

curl -i -X POST https://c2pa.mppfy.com/verify \
  -H 'content-type: application/json' \
  -H 'accept: application/vnd.x402+json' \
  -d '{"url":"https://example.com/signed.jpg"}'

# HTTP/1.1 402 Payment Required
# content-type: application/json
# {
#   "x402Version": 1,
#   "error": "X-PAYMENT header is required",
#   "accepts": [{
#     "scheme": "exact", "network": "base",
#     "maxAmountRequired": "10000",
#     "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
#     "payTo": "0x...",
#     "resource": "https://c2pa.mppfy.com/verify",
#     "extra": { "name": "USD Coin", "version": "2" }
#   }]
# }

Option B — pay with MPP (Tempo USDC)

# 1. Ask for a challenge
curl -i -X POST https://c2pa.mppfy.com/verify \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com/signed.jpg"}'
# → 402 WWW-Authenticate: Payment id="..." realm="c2pa.mppfy.com" method="tempo"

# 2. Pay the challenge with mppx SDK, then retry with Authorization: Payment <cred>

See mpp.dev for the mppx SDK.

Which protocol gets picked?

Detection (in order):

1. x-payment-protocol: mpp|x402 — explicit override wins over everything.
2. Authorization: Payment <cred> → MPP.
3. X-PAYMENT: <base64> → x402.
4. Accept: application/vnd.(mpp|x402)+json → soft hint.
5. Default: mpp (will flip to x402 after 7 days of clean shadow traffic — see docs/x402-roadmap.md).

---

Response shape

{
  "verified": true,
  "manifest": {
    "claim_generator": "Adobe Firefly 2.5",
    "signed_by": "Content Authenticity Initiative Intermediate CA",
    "signed_at": "2026-04-15T14:22:10Z",
    "assertions": [
      { "label": "c2pa.actions.v1", "action": "c2pa.created" },
      { "label": "stds.iptc.photo-metadata" }
    ]
  },
  "trust_chain": "valid",
  "warnings": []
}

trust_chain ∈ "valid" | "partial" | "unknown". partial means the chain validates but a leaf cert is outside the trust list (still useful for provenance, weaker guarantee).

---

Endpoints

Route	Auth	Price	Purpose
GET /	—	free	Service metadata + endpoint index
GET /llms.txt	—	free	Agent-readable service spec
GET /openapi.json	—	free	OpenAPI 3.1 + x402 accepts block
GET /health	—	free	Liveness probe
POST /verify	x402 or MPP	$0.01	Verify a C2PA manifest

Upload: multipart/form-data with a single file field (≤25 MB), image/video/audio. URL mode: JSON body { "url": "https://..." }, we fetch + verify server-side.

---

Architecture

• Runtime: Cloudflare Workers (single region-less deployment).
• Framework: Hono 4.x.
• C2PA engine: c2pa-rs compiled to WASM (7.5 MB raw, ~1.9 MB gzipped), embedded trust list.
• x402 SDK: x402 + x402/verify via PayAI facilitator.
• MPP SDK: mppx (Tempo chain).
• Observability: CF Analytics Engine + D1.

Source tree:

src/
  index.ts                   # Hono routes + openapi + llms.txt
  c2pa/                      # WASM loader + trust list artifacts
  _vendor/adapters/
    detect.ts                # protocol detection (pure function)
    multi.ts                 # dispatcher (routes verify/402/receipt)
    mpp.ts                   # MPP adapter
    x402.ts                  # x402 adapter
    x402-facilitator.ts      # facilitator client (PayAI on prod)
docs/
  x402-roadmap.md            # deferred work: CDP pool, stage 3, schema enrichment

Code under src/_vendor/ is shared MPPFY platform scaffold, scheduled for extraction into @mppfy/platform-core after M6. See src/_vendor/VENDOR.md.

---

Development

npm install
npm run dev                   # local :8787, PAYMENT_MODE=dev (no real payments)
npm run typecheck             # tsc --noEmit
npm test                      # vitest (detect, multi, x402-requirements)
npm run deploy:staging        # wrangler deploy --env staging
npm run deploy:production     # requires confirmation

Local smoke test:

# Dev mode — no payment required
curl -s http://localhost:8787/health

# Multi-protocol — expect 402 (MPP by default)
PAYMENT_MODE=multi wrangler dev
curl -v -X POST http://localhost:8787/verify -d '{"url":"https://..."}'
# → 402 WWW-Authenticate: Payment ...

# Force x402 challenge on same endpoint
curl -v -X POST http://localhost:8787/verify \
  -H 'x-payment-protocol: x402' \
  -d '{"url":"https://..."}'
# → 402 application/json with x402 accepts[]

---

Discovery & agent integration

• OpenAPI: c2pa.mppfy.com/openapi.json exposes both x-payment-info (MPP) and top-level x-x402.accepts[] (x402) so any agent SDK can pick its protocol without out-of-band knowledge.
• llms.txt: c2pa.mppfy.com/llms.txt — short prose spec for LLM-driven clients.
• PayAI Bazaar: auto-listed on first real x402 payment through prod.
• MPPScan: listed via MPP discovery.
• MCP server: mcp-server/ — @mppfy/c2pa-verify-mcp exposes verify_c2pa_manifest as an MCP tool for Claude Desktop / Cline / Cursor. Agent pays $0.01 via user-provided Base wallet transparently.

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Related

• MPP protocol: https://mpp.dev
• x402 protocol: https://x402.org · Coinbase repo
• C2PA standard: https://c2pa.org · c2pa-rs
• Content Authenticity Initiative: https://contentauthenticity.org
• MPPFY services: https://github.com/mppfy
• Roadmap: docs/x402-roadmap.md

License

MIT — see LICENSE.