Support for Subscription Add-ons / Modular Upgrades

[Anthonykung]

Summary:
It would be incredibly useful if Polar.sh could support subscription add-ons—modular, attachable products or features that can be added (or removed) from an existing subscription, both during checkout and after a subscription has started.

Description:
Currently, Polar treats each product as an independent subscription or one-time purchase. While this keeps things simple, there are many scenarios where customers or admins need to add optional features, seat upgrades, or services onto a base subscription—without requiring a separate checkout and billing cycle for each add-on. For example:

• Customers want to upgrade their plan with extra seats, advanced support, or premium features, billed as recurring add-ons.
• Admins need to provision (or remove) features dynamically for a customer, without canceling or recreating their main subscription.
• SaaS or API products often sell add-on modules, usage packs, or premium support separately but bundled into the same subscription invoice.
• Reduces customer friction: everything appears as a single subscription, a single bill, and is managed together.

Stripe, Paddle, and other platforms support add-ons, either as “subscription items” or additional prices. This unlocks more advanced pricing models (e.g., base plan + optional features, per-seat billing, pay-as-you-go modules) and lets both customers and staff manage subscriptions with more flexibility—without workarounds.

Why This Matters:
Supporting subscription add-ons would let us build more scalable, modular pricing for our SaaS products. Customers would have a single subscription, a single invoice, and a much smoother self-service upgrade path. It would also enable more flexible admin tools for support, migrations, or special cases—helping us serve our customers better and bring Polar in line with industry standards.

Thank you for considering!

[nate-oo]

This would be great also to have the ability to accept one-time bulk orders that a larger company may request if they like your product and want to purchase in bulk at a discounted price.

Flow:

1. Company contacts you
2. They say they want to buy your digital product (licenses/seats) in bulk
3. You create a quote or invoice with a discount applied
4. They pay accept the quote/pay the invoice at the discounted rate.