Overview

• Every request carries a revision header. Klaviyo versions the API by date and this plugin sends the revision it was built against.
• Bodies are JSON:API. A write is { data: { type, attributes } }. This plugin takes flat fields and builds that envelope; reads answer data plus links.
• Filters are expressions. filter is a string such as equals(email,"a@b.com"), combined with and() and or(). Field names and operators differ per resource.
• Paging is cursor-based. Pass the nextCursor from one response as cursor to read the next page. Klaviyo returns the cursor inside links.next as a full URL, and this plugin parses it out for you. The largest pageSize differs per route: 10 for lists and segments, 25 for tag groups, 50 for tags, 100 for profiles and 1000 for events. Metrics and webhooks take no page size.
• Subscription is a job. profiles.subscribe grants marketing consent, so Klaviyo queues it and answers 202 with no body. The result confirms the request was accepted, not that the profile is subscribed yet.
• Events are recorded by metric name, and Klaviyo creates the metric on first use. The event then counts towards any flow listening for it.
• Segments evaluate server-side. A new segment is not populated immediately, and its definition is a condition group rather than a filter string.
• Webhooks need a secret, and Corsair does not receive the deliveries. Klaviyo signs every delivery with the secretKey you set at creation. This plugin manages the webhook registrations; you host the endpoint that receives them and verify the signature there.
• Rate limits run a burst and a steady window per account, and a 429 carries Retry-After.

• 39 typed API operations

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Setup

npm install corsair @corsair-dev/klaviyo better-sqlite3
npm install --save-dev @types/better-sqlite3

yarn add corsair @corsair-dev/klaviyo better-sqlite3
yarn add --dev @types/better-sqlite3

pnpm install corsair @corsair-dev/klaviyo better-sqlite3
pnpm install --save-dev @types/better-sqlite3

bun add corsair @corsair-dev/klaviyo better-sqlite3
bun add --dev @types/better-sqlite3

import Database from 'better-sqlite3';
import { createCorsair } from 'corsair';
import { klaviyo } from '@corsair-dev/klaviyo';

export const corsair = createCorsair({
	plugins: [
		klaviyo(),
	],
	database: new Database('corsair.db'),
	kek: process.env.CORSAIR_KEK!,
	multiTenancy: true,
	hub: {
		projectApiKey: process.env.CORSAIR_API_KEY!,
		signingSecret: process.env.CORSAIR_SIGNING_SECRET!,
	},
});

klaviyo()

const { connectUrl } = await corsair.manage.connect.createLink({
	plugin: 'klaviyo',
	tenantId: 'acme',
});
// redirect the user's browser to connectUrl

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Example API calls

const tenant = corsair.withTenant('acme');
await tenant.klaviyo.api.profiles.list({ filter: 'equals(email,"jordan@acme.com")' });

const tenant = corsair.withTenant('acme');
await tenant.klaviyo.api.tags.create({ name: 'priority' });

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What’s next