COSAI.TAX
Built for Australian small business

Your books, done by Sai.
$1 a transaction.

Upload your bank statements (or connect your bank). Sai reads every line, posts it to the right account with the right GST, proves the balances to the cent, and prepares your BAS, payroll, super, TPAR and year-end. You just tick to agree.

No subscription. No minimum. 1,000 transactions is $1,000 + GST. A bookkeeper would charge $3,000–$6,000 for the same work.

Sai
Your bookkeeper, always on
Bank says
02 Jun · Direct Credit 158824 STRIPE · +$585.08
Sai posted
Dr Bank $585.08 · Cr Sales $531.89 · Cr GST $53.19
Stripe payout for customer sales — reported at G1 and 1A on your BAS. 96% confident.
AgreeChangeAsk Sai why

How it works

Upload or connect

Drop in your PDF bank statements, or connect your bank once. Sai reads every page and proves the running balance from opening to closing before anything is posted.

Sai posts every line

Debit and credit, correct account, GST default on and switched off where the law says so (wages, super, ATO, transfers, bank fees). Payroll and invoice payments are matched automatically.

You tick to agree

Every line comes with a plain-English reason and a confidence score. Agree, change it, or ask. Sai learns your business and stops asking.

The books prove themselves

Four BAS equal the P&L. Every bank closing equals the Balance Sheet. Nothing is lodged or closed with a red item. Your accountant gets a file that ties.

BAS with click-through to every line
Payroll, STP Phase 2, super (SG 12%), payslips
TPAR for contractors
Invoices, aged receivables, reminders
Bills by photo, payment runs, ABA files
Fixed assets & depreciation
Year-end close with lock and lodgement record
Evidence trail: bank says → software posted
Ask Sai anything about your numbers

Pricing you can count on

One number. Every bank line, invoice, bill, payslip or asset Sai processes is one transaction.

$1.00
per transaction + GST
  • No subscription, no minimum, cancel any time
  • First 100 transactions free
  • Monthly invoice with the full calculation, paid by direct debit or card
  • Re-coding or re-importing a line is never charged twice
  • Live meter in the app — you always know where you stand
300 txns / yr
Sole trader · $300
1,200 txns / yr
Tradie with staff · $1,200
4,000 txns / yr
Busy café · $4,000

Start now

Takes two minutes. Your first 100 transactions are on us.

Questions

Is Sai a registered tax agent?

Sai is software operated by CoSai Tax. Lodgement with the ATO is done by a registered agent (or by you through myGov/Online services) from the figures Sai prepares and proves. Every number has a trail back to the bank line.

What if Sai gets a line wrong?

You change it in one click. Sai learns the correction for your business and applies it from then on. Nothing is ever deleted — changes are recorded, and your accountant can see who changed what.

Cash or accruals?

Cash basis by default (the right answer for most small businesses). Accruals is a setting. Invoices you issue are tracked either way, and receipts that pay an invoice are never double-counted as sales.

Do I still need an accountant?

For tax returns and advice, usually yes — and they will love you, because the file arrives with four BAS tying to the P&L and every bank account tying to the Balance Sheet. Many accountants charge less when the books are clean.

Is my data safe?

Each business is walled off from every other. Statements are stored encrypted, bank logins are never stored by us (bank connection uses the Consumer Data Right through an accredited provider), and you can export everything at any time.