1. Overview

Uploaded documents, corrected values, the ledger, finding rules and your company details are saved in the browser. They stay in place after a refresh or a return visit. Uploaded files are read only inside this browser and are never sent anywhere.

Connected at rollout: reading PDF and photo (scanned) documents, AI-based document reading (currently read only by rules that look for the label before each field), linking to Hometax (Korea's tax portal) and accounting software, server storage for shared team use.

2. Challenges

1. Each document calls the same field by a different name.

‘공급가액’ vs ‘공급가’ (supply amount), ‘합계금액’ vs ‘총액’ (total), and dates like 2026.08.03 · 26-08-19 · ‘2026년 8월 12일’. Different names must still be read as the same field.

2. A number mistyped while copying only surfaces later.

One wrong digit in a business number or total goes straight into the ledger. Before adding, the check digit and supply amount + tax = total need to be verified.

3. You need to see where each value was read from.

Showing only the found value makes it hard to trust. Showing which characters in the original it came from makes checking fast.

3. Structure

Document check shows the document list, original text and found fields side by side in one place on the first screen. The ledger and finding rules have their own addresses, so they stay in place on back navigation and refresh.

4. Key Features

Found fields highlighted in the original

Eight fields — document type, document number, issue date, supplier, business number, supply amount, tax and total — are found, and the matching characters in the original are shaded in a different color per field. Dates are normalized to the 2026-08-03 format. When two companies appear, the one that isn't your company is taken as the supplier.

Math check — business number and total

It checks the business number's final check digit, supply amount + tax = total, and whether tax is 10% of the supply amount. While a problem remains, the add-to-ledger button is locked; fixing a field reruns the check right away.

Ledger — totals by month and supplier

Checked documents are added to the ledger and can be searched by month, supplier or document number. Counts and totals per supplier are shown, and the same supplier and document number can't be added twice. The CSV download also records which fields were corrected by hand.

Add finding rules

If a field isn't found, you add the label that appears before it (e.g. ‘공급금액’, ‘청구금액’). Adding a label rereads the uploaded documents, and values corrected by hand are left as they are.

• Pasted text and EUC-KR filesDocuments with no file, such as an email body, can be read by pasting the text. EUC-KR files saved from Excel or Notepad are read without broken characters.

6. QA

These are results from running the tool on PC 1440 and mobile 390 screens and tapping through in the order a real user would. We also checked that saved data is still found after a refresh. (2026-09-23)

The 17 function tests: load 6 sample documents (including EUC-KR) · highlight found fields in the original (8 fields) · read a document in a different format (quote, 26-08-19) · math check: business number check digit and total mismatch · fix a wrong field → check again · add to ledger · type a missing date by hand (2026.08.28) → ledger · add the remaining passing documents · block duplicates when the same document is uploaded again (your own file) · read your own EUC-KR file · view ledger after refresh · search ledger and totals per supplier · download ledger CSV · remove from ledger → kept after refresh · paste text → add a rule for a field not found · rule kept after refresh → reread and found · back navigation

Speed and quality scores (out of 100; mobile measured three times on a slow connection, median shown)

Mobile: First Contentful Paint 1.5s · Largest Contentful Paint 1.8s · Layout shift 0.00 · Blocking time 0ms PC: First Contentful Paint 0.4s · Largest Contentful Paint 0.4s · Layout shift 0.00 · Blocking time 0ms

7. Result