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SDK overview

Looking for refunds via the new agent SDK (@q3labs/pact-sdk)? See Agent SDK → Overview. That’s a different product — this page covers pact-monitor-sdk, the recording-only library.

pact-monitor-sdk is a thin fetch() wrapper that records every call’s outcome. Drop it in where you’d use fetch().

When to use the SDK vs Market

Section titled “When to use the SDK vs Market”
  • Refunds with zero work → use Market (host swap).
  • Can’t route through Market (contractual relationship, call must come from your IP) → use the SDK.
  • Contribute reliability data without enabling refunds → SDK with default config. No API key needed for local-only recording.

Install

Section titled “Install”
Terminal window
npm install @pact-network/monitor
# or
pnpm add @pact-network/monitor
# or
yarn add @pact-network/monitor

Requires Node.js 18+ (uses the built-in global fetch).

Minimal usage

Section titled “Minimal usage”
import { pactMonitor } from '@pact-network/monitor';


const monitor = pactMonitor(); // local only, no key required
const res = await monitor.fetch('https://upstream.example/v1/<path>', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'getBalance',
    params: ['...'],
  }),
});

That’s the whole basic API. monitor.fetch() signature matches fetch().

Modes

Section titled “Modes”
ModeConfigAPI key?What you get
Local onlypactMonitor()NoLocal recording, getStats(), getRecords().
Sync to backendpactMonitor({ syncEnabled: true, apiKey: '...' })YesLocal + records posted to the backend; contributes to the public reliability index.

The golden rule

Section titled “The golden rule”

The monitor never breaks the upstream call. Recording and sync are wrapped in try/catch; don’t add error handling that re-throws on monitor failures. If the SDK ever breaks an upstream call, file a bug.

Section titled “Cross-links”