Fidacy — Open verification + SDK

Open verification + SDK for Fidacy — the external, signed trust layer for agent payments.

Verify any Fidacy verdict yourself, against our public JWKS. Don't trust us — check.

Every verdict Fidacy issues is signed. These packages let you fetch our public keys and cryptographically verify that a risk payload or webhook genuinely came from Fidacy and was not tampered with — entirely client-side, with no need to call back to us.

"Anyone can verify" is a testable claim here, not a slogan: a conformance corpus ships signed fixtures plus expected outcomes, so a port of the verifier in any language proves compatibility offline (node packages/verify/conformance/run.mjs from the repo root, 8/8 or it is not compatible).

Packages

Quickstart

Run it in 30 seconds (assess + verify a real signed verdict):

git clone https://github.com/fidacy/fidacy-open && cd fidacy-open/quickstart
npm install
FIDACY_API_KEY=fky_test_…  node quickstart.mjs   # a TEST key from app.fidacy.com (mode: test)

Output: a signed verdict and signature valid: true — cryptographically verified against the public JWKS, client-side, with no call back to Fidacy. See quickstart/.

Or add the packages to your own project (published on npm, Apache-2.0):

npm i @fidacy/sdk @fidacy/verify

Python? Same flow, two dependencies — see quickstart-python/:

cd fidacy-open/quickstart-python && pip install -r requirements.txt
FIDACY_API_KEY=fky_test_…  python3 quickstart.py

import { Fidacy } from '@fidacy/sdk';
import { verifyRiskPayload } from '@fidacy/verify';

const fidacy = new Fidacy({ apiKey: process.env.FIDACY_API_KEY! });

// Assess a payment mandate (AP2 intent/cart).
const result = await fidacy.assess({
  mandate: {
    vct: 'mandate.payment.1',
    payee: { id: 'merchant_demo', name: 'Demo Store' },
    payment_amount: { amount: 4299, currency: 'EUR' },
    payment_instrument: { id: 'pi_demo', type: 'card' },
  },
});
console.log('decision:', result.decision);

// Don't trust us — verify the signed verdict yourself, against the public JWKS:
const verified = await verifyRiskPayload(result.riskPayloadJws);
console.log('signature valid:', verified.valid);
console.log('decisions match:', verified.claims.decision === result.decision);

Runnable end-to-end example: examples/quickstart-node.

Links

• Specification: spec/
• Hosted product: https://fidacy.com

Repository

Home: the canonical repository is https://github.com/fidacy/fidacy-open. Packages are published under the npm scope @fidacy (Apache-2.0).

Design principles

• Isomorphic. @fidacy/verify runs in Node 18+, the browser, and edge runtimes. No Node-only globals.
• Independent. These packages only call the public API and verify signatures. They contain no Fidacy proprietary logic.
• Auditable. Apache-2.0, open source, no secrets.

License

Apache-2.0 © 2026 ZEEPCODE GROUP LLC