Here's the lowdown
Lunar Papers turns a client's raw tax documents into organized workpapers, an early estimate and a list of missing items.
After the return is prepared elsewhere, the tool compares the PDF with the workpapers and flags differences for the firm to investigate.
Pricing starts at $79 for a standard Form 1040 workbook, plus $29 for its first return comparison.
The lonely reviewer problem
In a small tax shop, one person can prepare the return, review it and sign it. That is efficient right up until the same pair of eyes misses the same number twice. Here's the thing: a reviewer cannot surprise themselves.
Lunar Papers is built for that gap. The new tax engagement tool sits before and after a firm's normal tax software. It does not prepare or sign the return. It organizes the file, builds workpapers and gives the preparer another place to look for trouble.
That makes the product less like a replacement for professional judgment and more like a digital review desk. The firm still decides whether a flagged difference is an error, a valid tax treatment or simply a mismatch in how two systems display the same fact.
It starts before anyone keys the return
A firm uploads the documents exactly as the client sent them. Lunar Papers can split combined scans, stitch together photos and sort the file into workpaper tabs. It also identifies open items and drafts a client request list.
The system produces a provisional estimate of the refund or balance due before the return is keyed. That can help a preparer spot a missing payment, an expected K-1 or a sharp change from the prior year while there is still time to ask questions.
When new documents arrive, the workpapers and open-item list update. The goal is to avoid rebuilding the file every time a client finds one more form in an inbox.
Then comes the second pass
The firm prepares the return in its usual software and uploads the finished PDF. Lunar Papers compares that return with the workpapers, form calculations and source documents line by line.
A finding can show the workpaper amount, the return amount and where the preparer should look. The firm's team evaluates the difference and makes the tax call. Lunar Papers says its workpapers use live Excel formulas, source references, prior-year comparisons and tie-out checks so the path behind a number can be followed.
Because the comparison reads a PDF, it can work even when there is no direct connection to the firm's tax software. Direct integrations are planned, but they are not required for the current review step.
The price follows the return
There is no annual commitment or seat minimum. One standard workbook and its first comparison are free.
After that, a standard Form 1040 workbook starts at $79. Complex returns cost $149 and advanced returns cost $249, based on document count and complexity. Business-return workbooks for Forms 1120-S, 1065 and 1120 start at $99, with higher tiers at $199 and $299.
A 1040 comparison costs $29 the first time and $15 for each repeat. Entity-return comparisons cost $49 and then $25. The firm sees the tier before the workbook is built, but adding documents later can move the whole engagement into a higher tier.
The guardrails matter
Tax documents are not ordinary files. Lunar Papers says data is encrypted in transit and at rest, each firm's data is isolated, and AI processing runs on U.S. infrastructure under terms that prohibit training on client data.
The company also says firms must obtain client consent before a return comparison under Section 7216, the federal rule that limits how return preparers disclose or use tax information. Source documents can be deleted on a schedule set by the firm, while the workbook and audit trail remain.
The bigger limit is simple: software can point to a difference, but it cannot own the conclusion. For a solo preparer, Lunar Papers may add the second set of eyes that the org chart does not provide. The signature, and the responsibility behind it, still belongs to the tax professional.
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