Billing is where a lot of SaaS teams underestimate the work. "It's just charging a card every month" turns into proration, trials, upgrades, dunning, tax, and refunds — each an edge case that touches revenue. The first real decision: do you build the billing engine yourself, or buy one like Stripe Billing? Here is how we weigh it.
What "billing" actually includes
Before choosing, be honest about the scope. A production SaaS billing system has to handle plan changes with proration, free trials and grace periods, dunning (retrying failed payments before you lose the customer), metered and usage-based charges, coupons, tax calculation, invoicing, and refunds — plus a webhook pipeline that keeps your app's access in sync with payment state. Most of the cost is in these edges, not the happy path.
Buying a billing platform (Stripe, Chargebee, Paddle)
A billing provider gives you subscriptions, proration, dunning, tax, and PCI-compliant card handling out of the box, so you ship in days and never store card data. The trade-offs: a percentage fee on revenue, less control over exotic pricing, and a dependency you design around. Paddle and similar "merchant of record" providers go further and handle global sales tax and VAT for you — often worth it on its own.
Buy when…
- You want to launch fast and validate pricing before over-investing.
- Your pricing is standard — per-seat, tiered, or usage-based.
- You don't want to own PCI compliance or global tax.
Building billing in-house
A homegrown engine gives you total control over pricing logic and no per-transaction platform fee — attractive at very high volume or with genuinely unusual pricing. But you now own proration maths, retry schedules, tax rules that change by jurisdiction, PCI scope, and an invoicing system. That is a product in itself, and it needs maintenance forever.
Build (or go hybrid) when…
- Your pricing is too unusual for an off-the-shelf model.
- Volume is high enough that platform fees outweigh engineering cost.
- You still use a provider for card processing and PCI, but own the subscription logic on top — the hybrid most large SaaS companies land on.
Rule of thumb: buy the parts that are risky to get wrong — card handling, PCI, tax — and only build the logic that is genuinely unique to your business. Almost no one should build card processing from scratch.
The decision that outlives the choice
Whatever you pick, keep billing behind an internal abstraction rather than scattering provider calls through your app. A clean billing service — one place that knows about plans, entitlements, and payment state — lets you switch providers, add a second one for a new region, or migrate to a hybrid model later without a rewrite.
How FlexGrew approaches it
We start by mapping your pricing and compliance needs, then default to a provider for card handling and PCI while owning only the subscription and entitlement logic your product actually needs. We wire the webhook pipeline so access always matches payment state, and we keep it behind a billing service you can evolve. The result is billing that ships fast, stays compliant, and won't trap you as your pricing grows up.
Deciding how to bill for your SaaS? Talk to our team and we'll help you pick the shortest path to reliable, compliant billing.
