Lumimi CSV

Fast & Simple CSV Editor

Only for Mac

$9.99

Mac

The ultimate CSV editor for your Mac. JSON, images, encodings — every CSV headache, solved in one place. The ultimate CSV editor for your Mac. A whole JSON blob crammed into one cell. Timestamps that are just long numbers. Images as endless Base64. If you've ever opened a CSV and thought "I can't read any of this" — Lumimi CSV was built to fix exactly that. Native Swift 6, no Electron: it launches fast and stays fast. ■ A whole API response stuffed into one cell? The cell content viewer expands JSON into a collapsible tree — the structure at a glance. ISO timestamps become local time, big numbers get thousands separators, URLs break down parameter by parameter, HTML entities decode, XML is pretty-printed, and Base64 images render right there. Raw text is always one click away, and your data never changes. ■ Long cells that finally fit Rows containing newlines grow automatically so you can read the whole value. Double-click a column divider and the width snaps to the content. Even million-row files stay responsive. ■ Encodings that never bite Detects UTF-8, UTF-8 with BOM, UTF-16 LE/BE and Windows-31J (CP932), including vendor-specific Japanese characters. Delimiters, line endings and the BOM are written back exactly as opened, and every cell is checked on save: if a character can't be represented in the original encoding, Lumimi CSV shows you where it is and stops — instead of quietly corrupting the file. ■ Hand the tedious edits to AI Connect OpenAI, Claude, Gemini or Grok with your own API key. Ask about your data, then keep asking follow-ups in the same conversation. "De-identify all the data" — ask for edits and every change is previewed cell by cell before you apply it. Discard it, or apply it and undo everything with one ⌘Z. Save the prompts you use often as templates. Keys live in the macOS Keychain and only the tabs you select are sent. The feature is optional — every editing feature works without a key. ■ Faster every day • Open many CSV / TSV files as tabs; put the tab bar on any edge • Find and replace with match case, whole word and regular expressions • Click a column header to cycle ascending → descending → off, restoring the original row order • Rectangular selection, copy/paste across sheets, full undo/redo • Excel and JSON import / export • Atomic saves, and detection when a file changes outside the app ■ Also Nine interface languages: English, Japanese, Simplified and Traditional Chinese, Korean, German, French, Spanish and Brazilian Portuguese. Dark mode and adjustable font size. No analytics, no tracking, no ads.

Ratings & Reviews

  • This app hasn’t received enough ratings or reviews to display an overview.

Six more interface languages: Simplified Chinese, Korean, German, French, Spanish and Brazilian Portuguese — nine in total, switchable in one click.

Version 1.1.0

The developer, SHUJI HAYASHI, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    SHUJI HAYASHI
    Size
    3.2 MB
    Category
    Productivity
    Compatibility
    Requires macOS 14.0 or later.
    • Mac
      Requires macOS 14.0 or later.
    Languages
    English and 8 more
    • English, French, German, Japanese, Korean, Portuguese, Simplified Chinese, Spanish, Traditional Chinese
    Age Rating
    4+
    Copyright
    © 2026 Lumimi
  • Developer Website
  • Privacy Policy

    • Supports

    • Family Sharing

      Up to six family members can use this app with Family Sharing enabled.