Polar Integration

Polar Integration

Polar is a payment platform for digital products: subscriptions, one-time purchases, licenses, checkout, and webhooks. This skill provides complete integration guidance.

Integration Workflow

1. Determine the Stack

Identify the project's framework. Polar has first-class support for:

• Next.js via @polar-sh/nextjs — see references/nextjs.md
• SvelteKit via @polar-sh/sveltekit — see references/sveltekit.md
• Supabase via @polar-sh/supabase — see references/supabase.md
• Any JS/TS framework via @polar-sh/sdk — see references/typescript-sdk.md
• Python via polar-sdk — see references/python-sdk.md
• Other framework adapters: Astro, Express, Hono, Fastify, Remix, Nuxt, Elysia, Deno, TanStack Start, Better Auth

2. Install Dependencies

npm install @polar-sh/sdk
# For Next.js projects:
npm install zod @polar-sh/nextjs
# For SvelteKit projects:
npm install zod @polar-sh/sveltekit
# For Supabase projects:
npm install zod @polar-sh/supabase
# For embedded checkout:
npm install @polar-sh/checkout
# For Python projects:
pip install polar-sdk

Note: The Polar SDK is in active development. Pin versions to avoid breaking changes: npm install @polar-sh/sdk@^0.46 / pip install polar-sdk~=0.28

3. Configure Authentication

Set up environment variables:

POLAR_ACCESS_TOKEN=polar_at_xxx     # Organization Access Token from Polar dashboard
POLAR_WEBHOOK_SECRET=xxx            # Webhook signing secret

Create Organization Access Tokens from organization settings in Polar dashboard. See references/authentication.md for details.

For sandbox/testing, use server: "sandbox" in SDK config. For production, use server: "production" or omit. See references/sandbox.md for sandbox details (test cards, API URLs, limitations).

4. Set Up Checkout

Choose approach based on needs:

• Checkout Links: references/checkout-links.md
• Checkout API: references/checkout-api.md
• Embedded Checkout: references/checkout-embedded.md

Quick start (Next.js):

// app/checkout/route.ts
import { Checkout } from "@polar-sh/nextjs";

export const GET = Checkout({
  accessToken: process.env.POLAR_ACCESS_TOKEN,
  successUrl: process.env.SUCCESS_URL,
  server: "sandbox",
});
// Use: GET /checkout?products=PRODUCT_ID

Quick start (SDK):

import { Polar } from "@polar-sh/sdk";

const polar = new Polar({
  accessToken: process.env.POLAR_ACCESS_TOKEN,
  server: "sandbox",
});

const checkout = await polar.checkouts.create({
  products: ["PRODUCT_ID"],
});
// Redirect user to checkout.url

5. Set Up Webhooks

Webhooks notify your app about payment events (order created, subscription canceled, etc.).

Quick start (Next.js):

// app/api/webhook/polar/route.ts
import { Webhooks } from "@polar-sh/nextjs";

export const POST = Webhooks({
  webhookSecret: process.env.POLAR_WEBHOOK_SECRET!,
  onPayload: async (payload) => {
    // Handle any event
  },
  onOrderCreated: async (payload) => {
    // Handle new order
  },
  onSubscriptionCreated: async (payload) => {
    // Handle new subscription
  },
});

Quick start (Express):

import express from "express";
import { validateEvent, WebhookVerificationError } from "@polar-sh/sdk/webhooks";

app.post("/webhook", express.raw({ type: "application/json" }), (req, res) => {
  try {
    const event = validateEvent(req.body, req.headers, process.env.POLAR_WEBHOOK_SECRET ?? "");
    // Process event
    res.status(202).send("");
  } catch (error) {
    if (error instanceof WebhookVerificationError) res.status(403).send("");
    throw error;
  }
});

For webhook setup in Polar dashboard: references/webhooks-setup.md For local development with polar listen: references/webhooks-local.md For delivery handling, retries, troubleshooting: references/webhooks-delivery.md

6. Set Up Customer Portal (Optional)

Give customers access to their orders and subscriptions.

Next.js:

// app/portal/route.ts
import { CustomerPortal } from "@polar-sh/nextjs";

export const GET = CustomerPortal({
  accessToken: process.env.POLAR_ACCESS_TOKEN,
  getCustomerId: async (req) => "CUSTOMER_ID", // resolve from your auth
  server: "sandbox",
});

SDK:

const session = await polar.customerSessions.create({ customerId: "CUSTOMER_ID" });
// Redirect to session.customerPortalUrl

See references/customer-portal.md.

Reference Index

Load these files when you need detailed information on a specific topic:

SDK & Frameworks

• references/typescript-sdk.md — TS/JS SDK installation, quickstart, framework adapters list
• references/python-sdk.md — Python SDK installation, sync/async usage, sandbox config
• references/nextjs.md — Next.js route handlers for checkout, portal, webhooks, all webhook handler names
• references/sveltekit.md — SvelteKit integration with @polar-sh/sveltekit, file paths, examples
• references/supabase.md — Supabase Edge Functions integration with @polar-sh/supabase

Authentication

• references/authentication.md — OAT tokens, security, GitHub secret scanning
• references/oauth2.md — OAuth 2.0 flow, authorization code exchange, PKCE, org vs user tokens

Products & Pricing

• references/products.md — Creating products, pricing models, billing cycles, benefits, variants, archiving
• references/trials.md — Free trial periods, abuse prevention, managing trials on existing subscriptions
• references/seat-based-pricing.md — Team/B2B pricing, seat management, claim flow, API examples
• references/discounts.md — Percentage/fixed discounts, codes, restrictions, recurring options
• references/custom-fields.md — Custom checkout fields (text, number, date, checkbox, select)

Checkout

• references/checkout-links.md — No-code checkout links, query params, UTM tracking
• references/checkout-api.md — Programmatic checkout sessions, ad-hoc prices, multiple products
• references/checkout-embedded.md — Embedded checkout, JS library, React integration, events, wallet payments

Webhooks

• references/webhooks-setup.md — Creating endpoints, delivery format, secrets, event subscription
• references/webhooks-local.md — Local dev with Polar CLI (polar listen)
• references/webhooks-delivery.md — Validation, SDK examples, IP allowlist, retry logic, troubleshooting

Benefits & License Keys

• references/benefits.md — Benefit types (Credits, License Keys, File Downloads, GitHub, Discord, Custom), grant lifecycle, webhooks
• references/license-keys.md — License key validation, activation/deactivation, limits, brandable prefixes

Events & Metering

• references/events-metering.md — Usage-based billing, event ingestion, meters, cost tracking, credits

Orders & Customers

• references/orders-subscriptions.md — Sales overview, checkout statuses, payment attempts
• references/customer-portal.md — Customer portal URL, authenticated links via API
• references/refunds.md — Refund processing, webhook events, benefit revocation

Webhook Events

• references/webhook-events.md — Complete list of all webhook events, framework handler names

Metrics & Analytics

• references/metrics.md — Revenue, MRR, churn, conversion, AOV, cost insights

Customer State & Sandbox

• references/customer-state.md — Single API call for customer's subscriptions, benefits, meters; customer.state_changed webhook
• references/sandbox.md — Sandbox environment, test card numbers, API URLs, SDK config, limitations

API Reference

• references/api-reference.md — Complete list of all API endpoints, rate limits, pagination, scopes

AI Integration

• references/mcp.md — Polar MCP server for AI agents (Cursor, Claude, ChatGPT, etc.)