SaaS billing software: what it does and how to choose
SaaS billing software turns the subscriptions you sell into accurate invoices, collected payments and recognised revenue — recurring and usage charges, mid-term changes, renewals, tax and accounting, handled automatically. Bunny is SaaS billing, CPQ and RevOps for B2B SaaS. This guide covers what the category does, how product-led and sales-led billing differ, and how to choose.
What does SaaS billing software do?
Eight jobs, from the price on your website to the number in your board deck. A payment processor covers one or two of them. SaaS billing software covers the lot — and the good ones do it from a single record of what each customer bought.
Product catalog and pricing
Products, plans, price lists and charges — the catalog every quote, checkout and invoice draws from.
Pricing models explained →Subscription management
What each customer has right now, and every upgrade, downgrade, add-on, trial and cancellation, with proration.
Subscription management →Usage and metered billing
Ingest usage, rate it against tiers or bands and bill it in arrears next to recurring fees.
Usage-based billing → Metered billing →Invoicing and automation
Scheduled invoice runs, invoices, credit notes and tax, without a monthly billing week.
Billing automation →Payments and dunning
Card and bank payments, a portal to pay invoices, and reminders that chase overdue ones before they become involuntary churn.
Dunning management →Renewals
Auto-renewal for evergreen plans, renewal quotes for negotiated ones, and uplifts applied on time.
Renewal management →Quoting for sales-led deals
Custom prices, ramps and approvals, with the signed quote becoming the subscription.
CPQ for SaaS → Quote-to-cash →Revenue and reporting
Revenue recognition, deferred revenue, journal entries and SaaS metrics such as MRR and NRR.
Revenue operations software →How is product-led billing different from sales-led billing?
Product-led billing starts at a checkout page. Sales-led billing starts with a negotiated quote. Most B2B SaaS companies run both within a couple of years, and that is the moment a billing tool built for only one of them starts to cost you.
| Product-led (PLG) | Sales-led (SLG) | |
|---|---|---|
| Price | Published on the website, the same for everyone on a plan. | Negotiated per deal: overrides, discounts, multi-year terms and ramps. |
| How the deal starts | Signup or trial, then a card at checkout. | A quote, an approval, an e-signed order form. |
| How it changes | The customer upgrades, adds seats or cancels in a portal. | An account manager quotes the upsell or renewal against the live contract. |
| How it is paid | Card charged automatically each period. | Invoice on net terms, often by bank transfer, sometimes with a PO number. |
| What breaks first | The first custom-priced customer, who can no longer self-serve. | The handoff from quote to billing, rekeyed by hand on every deal. |
Both motions, one system
Bunny bills PLG and SLG customers from the same catalog and the same subscriptions, so a customer on negotiated pricing can still add seats in the portal, and a self-service customer can be upsold on a quote. See self-service for custom-priced customers and why sales-led billing is harder.
Already on Stripe?
Keep it. Bunny Sidecar syncs Stripe into Bunny, so self-service revenue keeps billing where it is while Bunny runs your sales-led deals, renewals and reporting across both.
Which pricing models should SaaS billing support?
Your pricing will change more often than your billing system. Pick one that handles every model below, including the hybrids, so the next pricing change is a catalog edit rather than a migration. Bunny supports all of them.
| Model | How it bills | Example |
|---|---|---|
| Flat rate | One price per period, billed in advance. | $500 a month for the platform. |
| Per seat | Unit price times a committed quantity, prorated when the quantity changes mid-term. | $40 per user per month. |
| Tiered | Each tier priced separately; units in a higher tier cost less. | First 10 users at $10, the next 10 at $8. |
| Volume | The tier reached sets the price for every unit. | 25 users, all at the 21+ rate of $6. |
| Bands | The quantity selects a band with a fixed price. | 100–499 seats for a flat $75. |
| Usage-based | Usage records aggregated (sum, max, average or last) and billed in arrears. | $0.01 per API call. |
| Committed + overage | A recurring fee in advance with an included allowance, plus overage in arrears. | $1,000 a month including 100,000 calls, then $0.01 each. |
| Ramps and uplifts | Prices or quantities that step up on an agreed schedule, or a percentage increase at renewal. | Year one at 500 seats, year two at 800; +5% each July. |
| One-time fees | Billed once, on the first invoice. | $5,000 implementation. |
Weighing up consumption pricing? Read our guide to usage-based pricing models and how Bunny handles usage-based billing for negotiated contracts.
How to choose SaaS billing software
Take these eight questions into every demo. Ask the vendor to show you, on screen, with your own pricing — not to tell you.
-
Can it bill your real pricing, including the messy deal?
Bring your most complicated contract: a ramp, a usage allowance, a discount that expires. If it needs a workaround in the demo, it will need one every month.
-
Does a mid-term upgrade prorate and co-term on its own?
Add seats halfway through an annual term and watch the invoice. Proration done by hand is where invoice errors come from.
-
Where do quotes come from, and who rekeys them?
If the signed quote lives in another tool, someone copies it into billing on every deal. Ask whether a quote can become the subscription directly — see quote-to-cash.
-
Can custom-priced customers still self-serve?
Many portals only work for list-price plans. Check that an enterprise customer on negotiated rates can add seats without emailing their account manager.
-
How are renewals handled?
Automatic renewal for evergreen plans, a renewal quote for negotiated ones, uplifts applied without anyone remembering. See renewal management.
-
What does finance get at month-end?
Journal entries to your ledger, revenue recognition from the contract, tax handled. Ask what is included and what is a separate product.
-
Will it grow into entities and currencies?
Your first international subsidiary should be a settings change, not a re-implementation. Ask about multi-entity billing early.
-
How is it priced as you grow?
Percentage of revenue, per seat, platform fee or a mix. Model the cost at today’s revenue and at three times it, including any add-ons you will need.
Four shapes of SaaS billing software
Every vendor claims to do everything. The useful question is where each one started, because that is the motion it still handles best.
Payments-first
Stripe Billing. Superb for self-service: checkout, cards, a customer portal, quotes and revenue recognition. Its newer usage-metering layer, Metronome, is priced separately from Stripe Billing. Sales-led teams usually outgrow it on negotiated contracts — see Bunny vs Stripe and running both.
Subscription billing suites
Chargebee, Recurly, Maxio. Built around recurring billing, then extended. Chargebee now markets its own CPQ, with revenue recognition sold as a separate product. Recurly is strong on subscriber retention and payment recovery, and does not market quoting. Compare Chargebee, Recurly and Maxio, or browse Chargebee alternatives.
Enterprise suites and CRM-native
Zuora, HubSpot Revenue Hub, Salesforce Revenue Cloud. Zuora sells Billing and Zuora Revenue as distinct products for large enterprises. HubSpot’s Revenue Hub, renamed from Commerce Hub, puts quoting, billing and payments inside the CRM. See Bunny vs Zuora and Bunny vs HubSpot.
Quote-to-revenue in one product
BunnyBunny started from the negotiated B2B deal: the quote, the subscription it creates, every change after it, and the invoice, renewal and revenue schedule that follow. Self-service runs from the same records. Read the buyer’s guide to CPQ for B2B SaaS if quoting is the bigger half of your problem.
How Bunny does SaaS billing
One product for the self-service checkout and the six-figure contract. Buy the motion you run today and add the other when you need it.
PLG
0.6% of PLG revenue
Recurring and usage-based subscriptions, card and bank payments, the customer portal, QuickBooks Online and Xero sync, HubSpot integration and SaaS analytics.
SLG
$150 per user per month
Everything in PLG plus Bunny CPQ: quotes for new deals, upsells and renewals, custom pricing and ramps, approval workflows, Salesforce integration and e-signature.
Advanced Billing
+0.2% of PLG and SLG revenue
Multiple legal entities, account hierarchies, multiple currencies and ASC 606 revenue recognition, built from the same contracts that drive the invoices.
Then ask it questions
Because quotes, subscriptions, invoices and revenue share one data model, the Bunny RevOps Agent can answer MRR questions, draft renewal quotes and flag overdue accounts on live billing data. Full plan details are on pricing.
Compare Bunny with other billing platforms
Weighing up more than one option? Here is how Bunny stacks up against the other platforms B2B SaaS teams shortlist most often.
- Bunny vs Chargebee A broad subscription suite. Bunny is built around the negotiated deal.
- Bunny vs HubSpot A powerful CRM that stops short of being a billing system.
- Bunny vs Maxio Capable, but assembled from SaaSOptics, Chargify and RevOps.io rather than built as one platform.
- Bunny vs Recurly Built for consumer subscriptions rather than sales-led B2B deals.
- Bunny vs Stripe Excellent for self-service checkout, thin on complex B2B pricing.
- Bunny vs Zuora Enterprise-grade, with the cost and 6–12 month implementation to match.
The RevOps expert your team never had.
- Type "send upgrade quotes to all starter plan accounts" — done in seconds
- Know which renewals need you this month, while there is still time to do something about it
- Find every overdue invoice in one question, instead of one account at a time
No credit card required. Cancel anytime.