Polar SDK integration

A standalone guide to wiring up Polar's three core HTTP endpoints — Checkout, Customer Portal, and Webhooks — using @polar-sh/sdk directly. The recipes are framework-agnostic Web Standards (Request/Response); each section also lists the small idiomatic adjustments per framework.

Setup

Install the SDK. Version 1.0 and later needs Node.js 22 or newer:

npm install @polar-sh/sdk
# or pnpm / yarn / bun

If the project already uses @polar-sh/sdk below 1.0 (signs: new Polar(...), camelCase fields such as successUrl, imports from @polar-sh/sdk/webhooks), upgrade it first by following the migration guide. Don't mix the old and new conventions.

Don't install the deprecated @polar-sh/<framework> adapters (@polar-sh/express, @polar-sh/hono, @polar-sh/fastify, @polar-sh/elysia, @polar-sh/astro, @polar-sh/sveltekit, @polar-sh/remix, @polar-sh/deno, @polar-sh/supabase). @polar-sh/nextjs, @polar-sh/nuxt, @polar-sh/tanstack-start and @polar-sh/better-auth are maintained; keep them if the project already uses them.

Required environment variables (use whatever loader your framework provides — process.env, Deno.env, import.meta.env, etc.):