saas-billing

SaaS Billing Expert (2026 Edition)

English | Bahasa Indonesia

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English

Orchestration & Integration

Connects and orchestrates with relevant domain skills like brainstorming, zero-to-prod-orchestrator, and project-context-mapper to ensure cohesive execution.

Description

Expert guide for implementing and auditing SaaS billing systems. Covers subscription state machines, secure webhook handling, database synchronization, and the 2026 billing landscape including Stripe, Polar.sh (open-source, developer-first), LemonSqueezy, PayPal, and Midtrans (for Southeast Asia).

Trigger Conditions

• Integrating any payment gateway (Stripe, Polar.sh, LemonSqueezy, Midtrans, PayPal) into a SaaS application.
• Using a Static-to-Dynamic QRIS alternative (with unique nominals and mutation webhooks) for local developers without PG accounts.
• Implementing subscription state machines (active → past_due → canceled → reactivated).
• Building secure webhook handlers with signature verification and idempotency.
• Syncing external subscription status to a local database.
• Implementing usage-based billing or metered API pricing.
• Building the customer billing portal (manage subscription, download invoices).
• Auditing an existing billing system for security gaps.

2026 Billing Provider Landscape

Provider	Best For	Open Source	Merchant of Record
Stripe	Enterprise, global, complex billing	❌	❌
Polar.sh	Developer-first, open-source products	✅	✅ (optional)
LemonSqueezy	Indie hackers, simple pricing, global	❌	✅
Paddle	B2B SaaS, EU VAT compliance	❌	✅
Midtrans	Southeast Asia / Indonesia	❌	❌
PayPal	Global, consumer trust	❌	❌

Merchant of Record (MoR): The provider handles tax compliance (VAT, GST), chargebacks, and legal liability — ideal for small teams without a finance department.

Polar.sh — Developer-First Billing (2026 Rising Star)

Polar.sh is the modern, open-source alternative to Gumroad/LemonSqueezy, purpose-built for developers and open-source projects:

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

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

// Create a checkout session
const checkout = await polar.checkouts.custom.create({
  productId: "prod_xxxx",
  successUrl: "https://myapp.com/success?checkout={CHECKOUT_ID}",
  customerEmail: user.email,
  metadata: { userId: user.id },
});

// Redirect to checkout
return redirect(checkout.url);