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TypeScript SDK

The package is @flammafex/freebird:

npm install @flammafex/freebird

The SDK requires Node.js 24 or newer. It provides ESM and CommonJS builds, TypeScript declarations, and uses the platform fetch implementation.

Supported client flows

The SDK supports the active V4 private-token flow through issueToken, checkToken, and verifyToken; V4 also has bounded issueTokens and verifyBatch operations.

import { FreebirdClient } from '@flammafex/freebird';

const client = new FreebirdClient({
  issuerUrl: 'https://issuer.example.com',
  verifierUrl: 'https://verifier.example.com',
});

await client.init();
const token = await client.issueToken();
const checked = await client.checkToken(token); // does not consume
const verified = await client.verifyToken(token); // consumes once

The SDK binds Sybil proofs to the exact V4 request. Create a fresh proof when request data changes or a retry requires a new request; do not reuse a proof across different bodies.

Configuration highlights

issuerUrl is required. verifierUrl is required for remote checks; V4 scope overrides, token storage, a custom fetch, optional proof-of-work settings, and the bounded batch body limit are optional. MemoryTokenStore is process-local; StorageTokenStore provides persistence appropriate to its runtime. SDK configuration does not replace issuer/verifier TLS, Redis, key, or persistence configuration.

Safe handling

  • Treat tokens, blinding state, Sybil proofs, and discovery-derived material as sensitive application data.
  • Never log blinding state, proof material, bearer bodies, private keys, or status capabilities; keep them out of analytics and URLs.
  • Use HTTPS service URLs.
  • Use typed FreebirdError.code values rather than matching human-readable error messages.
  • A local checkToken is non-consuming; verifyToken consumes and replay protection is a service-side property backed by the verifier's configured replay store.

The SDK does not make an application anonymous, authorize a user, or turn a development deployment into a production security boundary. See Production Deployment and Client Sybil Proofs for deployment and proof responsibilities.