Core / Node.js SDK | Documentation

The Core SDK is the shared base SDK used by the browser wrappers and by custom Node or JavaScript integrations.

Install

npm install @flash-analytics/sdk@2.2.0

pnpm add @flash-analytics/sdk@2.2.0

Initialize

import { FlashAnalytics } from '@flash-analytics/sdk';

const analytics = new FlashAnalytics({
  appId: process.env.FLASH_ANALYTICS_CLIENT_ID!,
  secretKey: process.env.FLASH_ANALYTICS_SECRET_KEY!,
  endpoint: 'https://api.flashanalytics.app',
  platform: 'node',
  appVersion: '1.2.3',
  buildNumber: '120',
  captureVariants: true,
});

Core APIs

await analytics.identify({
  profileId: 'user-123',
  email: 'user@example.com',
});

await analytics.track('job_completed', { queue: 'imports' });

analytics.setGlobalProperties({ plan: 'pro' });

const session = analytics.getSession();

Experiments

Enable captureVariants to keep a local cache of assignments in sync automatically. On each new session all experiments are fetched; after identify() only profile-mode assignments are refreshed; on session expiry only session-mode entries are removed.

// All cached assignments — no API call
const all = analytics.getAllExperiments();

// Single experiment — checks cache first, falls back to API if not found
const assignment = await analytics.getExperimentById('checkout-cta');
console.log(assignment?.variantName);

// Manual assignment (always calls the API)
const assignments = await analytics.autoAssignExperiments();
const variant = await analytics.assignExperiment('checkout-cta');

Remote config

const config = await analytics.fetchRemoteConfig({
  country: 'IN',
});

const featureFlag = config.getBoolean('feature_flag', false);
const welcomeText = config.getString('welcome_text', 'Welcome');
const maxItems = config.getNumber('max_items', 10);
const theme = config.getJson('theme_config', {});

Remote config automatically includes platform, app version, build number, identified profile ID, primitive global properties, language, country, and a random seed where available.