The post-month-end integrity check for Xero

June is signed off and sent. Someone just posted an invoice into March. Would you know?

Nobody re-runs three closed months to check the figures still agree; that's exactly how it slips through. Postlock does it for you: lock the month at sign-off and it watches from there. If anything lands in a closed period, you get the document, the person and the date by the next morning.

Check my closed months · free Try it on a demo company

Read-only. Postlock can never change your Xero data; it only watches and reconciles.

Caught automaticallyPosted 4 days after sign-off · attributed to T. Okafor.

postlock.co/integrity

September 2026Locked · signed offLocked · review compared with live Xero just now

No changes since sign-off1 unacknowledged change since sign-off Clean Action

Account	Was	Now	Movement
Retained Earnings	1,284,500.00	1,284,500.00	-

Document posted after sign-off

Type	Ref	Posted	By	Amount
Payment	BACS-4471 Pennine Supplies Ltd	04 Oct 16:22	T. Okafor	2,000.00

Caught the next morning. Would you have known?

By finance professionals, for finance professionals Read-only · technically incapable of touching your ledger No AI · same inputs, same answer, every time £0 to find out · free closed-months check

The problem

It's the night before the accounts go out to investors.

The setup

March, April and May are closed. The management accounts are ready to send to potential investors.

A hunch

Before you send them, you log into Xero and check that net profit for those three months still matches the accounts.

The realisation

March has moved by £10,000. You reported a £4,000 profit; Xero now shows a £6,000 loss. Something changed in a month you closed weeks ago, and nothing tells you what.

The evening

You download the P&L and go line by line, hoping it's one invoice that sticks out. It isn't: it's four new invoices and three credit notes among 200 transactions. Patch it with a journal? Resend and hope? This is the problem Postlock exists to solve.

Caught automaticallyAttributed to T. Okafor. No evening lost.

postlock.co/integrity

September, signed off · nothing's movedThe next morning, in Postlock Clean Action

Try it: this is really how Postlock looks. Read-only demo data, nothing is sent anywhere.

What	Who	Movement
Retained Earnings via BACS-4471 · 04 Oct	T. Okafor	−2,000.00

September 2026Locked · signed offLocked · review

A real payment, backdated into a signed-off month. Click the button to watch Postlock catch it.

The relief

Imagine finding out by the next morning.

Postlock snapshots every balance when you lock the period, then re-checks it for you on a schedule. If anything moves, the next check flags it: one screen shows exactly what, who and when, so you act in minutes, not an evening.

01 · SEE

What changed

The line, the old value, the new value, the movement - laid out like a working paper.

02 · WHO

Who & when

The exact document and the person in Xero who posted it, with the timestamp - straight from Xero's history.

03 · FIX

Put it right

Open the document in Xero, re-date or reverse it, then re-run the check until it's clean.

Suggested correcting journal - roadmap

And it guards the figures you already reported. You told the board profit was £25,410. Is it still?

Pin the headline numbers from your pack (net assets, revenue, profit) and Postlock re-checks each against Xero. If one moves it tells you in plain English: “March profit was reported at £25,410. It now stands at £24,760 - a £650 reduction since you signed off.” The figures you stand behind stay true.

Board figure · tracked

Net profit · March 2026

24,760.00

✗ Changed by −650.00 since sign-off - you reported 25,410.00. Update the pack, or restore the closed month.

Re-checked against Xero · flagged automatically

Why Postlock

Not another close tool. A watchdog for after you close.

Close tools automate the month-end, then stop at sign-off. Postlock starts there. It isn't twenty features you'll never use; it's one job done properly: proving the numbers you sent out are still the numbers. No AI anywhere, read-only by design, nothing to migrate.

The point

An automatic watchdog on closed periods

Snapshot every balance at sign-off, and Postlock watches on a schedule - so anything posted into, or backdated out of, a closed period is flagged within hours. It identifies the document and who posted it from Xero's history, and makes you record a reason before accepting it. You never have to remember to look.

And every sign-off keeps a manifest of the documents behind it. Re-date one out of a closed month and Postlock states what it was dated when you signed: "was dated 30 Jun, now 1 Jul". Void or delete one and that becomes a named finding too. Proof, not inference - and it's yours from the first month you lock.

“But doesn't Xero have lock dates?” Lock dates are a gate, not a witness. An admin can lift one silently, they don't snapshot the numbers you signed off, they never alert you when something moves, and they never make anyone explain the change. Postlock does all four.

See it on your own numbers - check your closed months free

The bonus

An Excel pack that's yours to keep

Most close tools keep your reconciliations inside their own dashboard. Postlock exports a genuine working-paper-quality Excel pack - cover, balance sheet, rec index, supporting schedules and a post-lock change log - because auditors and accountants live in files, not dashboards.

And the schedules carry live formulas, plus blank prepayments, accruals and fixed-asset templates: download it once and you can roll it forward yourself, forever, subscription or not. We'd rather earn next month than lock you in for it.

Who it's for

Built for the people who sign the numbers.

Accountancy practices

Every client's filed year-end against Xero today, on one screen - chase the 3 clients that moved, not the 200 that didn't.

Postlock for practices

Finance managers & CFOs

You signed the pack; Postlock keeps it true. If anything lands in that period afterwards, you hear first.

Postlock for finance teams

How it works

Four steps, every month.

Pull & reconcile

Balance sheet from Xero, line by line - status, this month's note, and each balance's carried-forward memory.

Prove with schedules

Attach a movement schedule, proof or expected value to any line. Totals tie to the GL and roll forward on their own.

Lock the period

Sign off and Postlock snapshots every balance - your line in the sand.

Watch & pack

Postlock re-checks the period every hour, flags anything that moves and names who did it - then exports it all as an Excel pack.

And you keep closing exactly the way you close now.

Excel working papers, a checklist tool, close automation, or nothing but Xero itself: Postlock doesn't run your close and doesn't replace anything in your stack. It connects read-only to the ledger underneath and watches what you signed off, after everyone else has moved on.

Postlock the integrity layer · watches after sign-off June 2026 Locked · snapshotted June still agrees with sign-off Backdated into June · JNL-0098 · B Khan

However you close · any of these, or none Excel working papers Close checklist Close automation Just Xero

X Xero the ledger · where the numbers live INV-2041 BILL-0887 JNL-0098 · dated 12 June

Nothing to migrate, nothing to rip out. Your close stays yours; the ledger gets a witness.

No sales calls. Ever.

Other tools make you book a demo.
Ours is a link.

Every close tool wants you on a call with their sales team before you can see the product. We think that's backwards. Here's the live demo - click around a real month-end, no signup, no card, no strings. Like it? Sign up and you're working in minutes.

Open the live demo Prefer to talk first? Book a call

The call is with the founder, not a sales team - and it's for your questions, not our pitch.

A note from the founder

"I'm a finance manager, and I sign off month-ends myself. Once the accounts go out, nothing in Xero tells you when a number in a closed month quietly changes; you find out at year-end, or worse, when someone else does. Postlock is the tool I wanted on my own desk: it records what you signed, watches it, and names what moved. It is read-only by design, there is no AI anywhere near your ledger, and everything it produces is yours to keep even if you leave."

James Howard ACA · founder, Postlock · talk to me directly · why it's built this way

Why trust an early product?

Because it can't hurt you: the Xero connection is read-only and technically incapable of writing, the checks are deterministic, and the Excel pack and every export work with or without a subscription. The worst case is a free report you didn't need.