Most small businesses don't choose an accounting tech stack. They accumulate one.
Year one, there's QuickBooks and a bank account. Year two, someone adds a payroll app. Year three, a bill pay tool, a corporate card with its own receipt app, Stripe for online payments, and a CRM that "syncs with QuickBooks" in a way nobody fully understands. Now there are seven apps in the group chat, everyone's talking, and nobody's sure who confirmed the dinner reservation.
This guide maps a typical small business accounting software stack: what each piece does, how it should connect to the ledger, and where the same dollar tends to get counted twice.
The center of the stack: your general ledger
Everything orbits the general ledger, which is the official record of every transaction in the business. For most small US businesses that's QuickBooks Online or Xero (if you're still choosing, our QuickBooks Online vs Xero comparison covers the differences).
Every other tool in the stack is either a source of transactions or a helper for one. The ledger is where they all have to agree. If an app's numbers and the ledger's numbers don't match, the ledger is the one your CPA, lender and investors will see, so that's where the fix has to land.
What connects to what in a small business accounting software stack
Here are the usual pieces and how each should feed the ledger.
Bank and credit card feeds. These bring in every cash movement. They're the backbone, and every other integration has to play nicely with them.
Payroll. A payroll app (Gusto, ADP, QuickBooks Payroll and so on) calculates pay and taxes, then posts a journal entry to the ledger: gross wages as expense, employer taxes as expense, withheld taxes as a liability, and net pay as cash out. The bank feed then shows the actual withdrawals, which should be matched to that entry, not added again. Our article on outsourced payroll services goes into what to hand off there.
Bill pay. Tools like Bill.com or Ramp's bill pay record vendor bills as accounts payable (money you owe) and then record the payment. When the payment clears the bank, the bank feed should match it to the existing bill payment, not create a new expense.
Expense cards and receipt capture. Corporate cards with their own apps can push each transaction with a receipt and category into the ledger. Good for clean books, but only if you turn off or ignore the regular bank feed for that same card. The receipt side of this is covered in our guide to receipt management for small business.
Sales and payments. Invoicing, Stripe, Shopify, Square and similar tools record sales, then pay out to the bank, usually net of fees and refunds. The ledger needs the gross sale, the fees and the refunds. The net deposit alone hides two of those three.
CRM and project tools. Usually these shouldn't post accounting entries at all. They're great for knowing which deals are coming. Let the invoicing system create the invoice.
Where bill pay and payroll integrations go wrong
The stack problem we run into most is double counting. It happens when two connected apps both record the same money.
Say a bill pay tool records a $4,800 payment to your IT contractor. The bank feed also shows "BILL.COM $4,800," and someone clicks Add instead of Match. Now that contractor has been expensed twice, your P&L is $4,800 worse than reality, and the books show the cash leaving twice. A careful bank reconciliation would flag the extra payment. Without one, it sits there until someone asks why IT cost so much this year.
Bill pay and payroll integrations each need a rule about which side creates the entry and which side only matches. Write that rule down.
Other common snags:
- Payroll mapped to the wrong accounts, so employer taxes land in wages or vice versa.
- Payment processors posting only net deposits, so revenue is understated and fees disappear.
- An old integration still connected after you stopped using the app, posting odds and ends.
- Two people setting up the same sync from different apps.
A worked example: mapping a 20-person consultancy's stack
Say you run a hypothetical 20-person consultancy. Your stack looks like this:
- QuickBooks Online: the ledger.
- Business checking and one credit card: bank feeds into QuickBooks.
- Gusto: payroll, posts one summary journal entry per payroll run.
- Bill.com: vendor bills and approvals, syncs bills and payments.
- A corporate card with receipt capture: syncs each charge with a receipt.
- Stripe: client card payments, deposits net of fees.
- HubSpot: sales pipeline, no accounting entries.
A one-page map for this stack would say, for each app, what it creates in QuickBooks and what the bank feed should do in response. For Gusto: creates the payroll entry; bank feed matches the net pay and tax withdrawals. For Bill.com: creates bills and payments; bank feed matches. For the corporate card: creates each expense; its bank feed is disconnected. For Stripe: gross sales and fees recorded through a clearing account, and the bank feed matches the net payout.
That page takes an afternoon to write. It saves you from every future month where someone wonders why the card shows up twice.
Five questions to ask before you add another app
- What will this app create in the ledger: bills, expenses, sales, journal entries, or nothing?
- Does it post detail (every transaction) or a summary (one entry per day or period)?
- Which accounts does it post to, and who decided?
- Will the bank feed need to match its entries, and does everyone know that?
- Who reviews the sync each month to catch errors?
The stack is the easy part
A great set of apps still needs people and a routine around it: someone who reviews the syncs, reconciles every account and closes the month. We wrote about that in the difference between a bookkeeper and a financial system. The software handles the volume. The people make it correct.
Questions owners ask
What software does a small business need for accounting?
At minimum, a general ledger like QuickBooks Online or Xero with bank feeds. Most growing businesses add payroll, bill pay and receipt capture. Add tools only when they solve a real problem, and decide how each one posts to the ledger before connecting it.
Why are my expenses doubled in QuickBooks?
Usually two sources recorded the same transaction, such as a bill pay sync and the bank feed, or a card app and the card's bank feed. Match bank feed transactions to existing entries instead of adding them, and disconnect duplicate feeds.
Should every app sync directly to QuickBooks?
No. Sales pipeline and project tools usually shouldn't post accounting entries. Only connect apps that are the true source of a transaction, and keep a written map of what each sync creates.
Want your stack mapped for you?
If your apps are all talking and nobody's sure who's in charge, our fractional accounting department can map the stack, fix the syncs and run the monthly review. For more practical notes on books, closes and systems, subscribe to The ABFI Accounting Brief.