Mercury Books vs Poof: Bookkeeping Inside the Bank, or Books You Can Defend

Mercury launched Books on September 16, 2026. If you bank with Mercury, it is free until the end of the year and $35 a month after that. If you have been paying for bookkeeping software, that number is going to get your attention, and it should. Here is an honest read on what it is, who it is for, and where it stops.

What Mercury Books is

Mercury Books is accounting inside the bank account. Your Mercury transactions are the books: the AI categorizes them as they land, the reports read from the same data, and there is no export, no sync, and no second login. That is the whole pitch, and for the business it is aimed at, it is a good one.

The pricing is straightforward. Subscribe on or before December 1, 2026 and the fee is waived through December 31. After that it is $35 a month. Subscribe on or after December 2 and you may get one month waived instead.

Who it fits

A founder with one Mercury account, a few hundred transactions a month, no invoices to chase, and a CPA who wants a clean P&L at year end. For that business, Books removes a tool from the stack, and removing a tool is worth more than any feature.

Where it stops

Three places, in the order they will matter to you.

It only sees Mercury. Books is a feature of the account. If your operating account is at Chase, your card is with Amex, or you keep a credit union account for the line of credit, that activity is not in Mercury Books. Most businesses past their first year bank in more than one place. Poof connects any bank and card through Plaid, and imports statements as CSV or PDF for anything older than the sync window.

It is not the business, it is the ledger. Invoicing, estimates, taking a card or ACH payment, budgets against actuals, a twelve-month cash forecast, per-job profitability: these are where a small business actually lives, and they are what Poof does around the books. Mercury Books reads the bank; Poof runs the back office with the books at the center.

Nothing waits for you. This is the one that decides it. In Mercury Books the AI's categorization is applied. In Poof, every entry the AI proposes stages as a card with the evidence it found: the five prior transactions for that merchant, the customer it resolved, the amount, the account. You approve it, approve part of it, or reject it with a reason that is recorded. When you have approved the same kind of work a few times, you grant a rule from the card in front of you, and that rule stops itself the first time you contradict it. Nothing reaches the books unseen.

For a solo founder that may be more ceremony than they want. For anyone who has ever had to explain a number to a lender, an auditor, or a partner, it is the difference between books that were done and books you can defend.

The honest comparison

Prices checked September 17, 2026. Mercury's terms can change; verify before you decide.

What I would do

If you bank with Mercury and your books are simple, use Mercury Books through December and see if you miss anything. You will know by February.

If you have more than one account, send invoices, need to know whether a job made money, or keep books for other people, the free months are not the number that matters. The number that matters is what a wrong entry costs you at tax time, and whether you would have seen it before it posted.

For a broader look at the field, see the best QuickBooks alternatives for small business. For how Poof's approvals inbox works in practice, the homepage is a working demo.

*Written by Austin Semple, a former controller: three years in audit, seven running the books for small businesses, and the founder of Poof. Poof is one plan at $79/mo with every feature included, and a close within five business days or the next month is free. Start a 30-day trial, no card required.*