Who changed your books, and when.
PeriodGuard keeps a full history of every change to your accounting records: who made it, when, and every value before and after. When anything changes in a month you have already closed, it emails you and your accountant. It only reads your books, never changes them.
PeriodGuard works with one cloud accounting platform today; you see which when you connect.
An email PeriodGuard sends
A change in a closed period: Harbour Bakery
Invoice INV-0041 · Harbour Café: edited 3 Feb 2026, 08:47 UTC. Dated 14 Jan 2026, on or before your closed-through date. Who: Sam Lee.
Line 1 › Unit amount: 300 → 237.5
An example; the names and amounts are made up.
Every change, kept
PeriodGuard reads your books with read-only access and keeps every version of every invoice, bill, payment, bank transaction, manual journal, credit note, contact and account. When something changes, you see exactly which values changed, from what to what.
Who and when
Each change shows who made it and when, from the accounting software's own history of that record. Filter by person, kind of record, dates or a word, and download it all as CSV.
Closed months stay closed
When a record dated in a month you already closed is edited, voided or back-dated, you and your accountant get an email. PeriodGuard uses your accounting lock dates, or a closed-through date you set, and tells you when a lock date is moved back.
What the history looks like
Two changes to records dated in January, made after January was closed. An example with made-up names and amounts.
| When | Record | Who | What changed |
|---|---|---|---|
| 3 Feb 2026, 08:47 UTC | Invoice INV-0041 · Harbour Café Edited · Invoice or bill · dated 14 Jan 2026 Closed period closed through 31 Jan 2026 | Sam Lee |
|
| 2 Feb 2026, 15:58 UTC | Bill FC-7781 · Flour & Co Voided · Invoice or bill · dated 3 Jan 2026 Closed period closed through 31 Jan 2026 | Jo Park |
|
For accountants and bookkeepers
Connect your clients and see them side by side: who is watched, what is closed, how many changes landed in a closed period this month. Each client gets a plain report of the changes in a period, before and after, who and when, to print or download. From $9.90 a client a month, with no fee per person.
For agents
The same history as one POST with filters, described by an OpenAPI 3.1 document, and an MCP server that gives it to an agent as a tool: what changed in a closed month for this client since Friday. Past the allowance, a query costs $0.01.
What it does not do
- It never changes your books. It asks your cloud accounting software for read access only.
- It sees changes at its next snapshot, up to an hour later on a paid plan.
- It starts the day you connect. Earlier changes have no before value to show.
- Payroll is not covered yet. The books are: sales, purchases, banking and journals.
- Your data is yours. It is never sold, shared or used to train AI, and it is deleted when you disconnect.
- It is not an audit. It is a record of what changed, for you and your accountant.
Plans
Free for one business with the last 30 days of history. Business: $19/month for one business, every change kept. Accountants: from $99/month for 10 clients.
Get early access
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