Free LINE Flex Message Editor
Build LINE Flex Messages without writing JSON by hand. This free Flex Message editor lets you add bubbles and carousels, arrange boxes, text, images and buttons, preview exactly how the message will look on LINE, then export clean JSON you can drop straight into your LINE Official Account or Messaging API. It runs entirely in your browser — your work is saved locally and never uploaded.
How to use
- Pick a template or start from a blank bubble.
- Add and arrange boxes, text, images and buttons in the visual editor.
- Watch the live preview update as you edit.
- Export the Flex Message JSON and paste it into LINE OA or the Messaging API.
Features
- Visual drag-and-drop editor — no hand-written JSON
- Supports bubble and carousel container types
- Live preview that matches how LINE renders the message
- One-click export of valid Flex Message JSON
- Runs 100% in your browser; designs are saved in local storage
- Hardened with a strict content-security policy against script injection
Frequently asked questions
Is the Flex Message editor free?
Yes — it is completely free with no sign-up. The editor runs entirely in your browser and stores your work in local storage, so nothing is sent to a server.
What is a LINE Flex Message?
A Flex Message is LINE's flexible message format defined as JSON, letting you build rich cards with custom layouts, images and buttons instead of plain text.
Where do I use the exported JSON?
Paste it into the LINE Official Account Manager's Flex Message field, or send it via the LINE Messaging API as the "contents" of a flex message.
Is my design uploaded anywhere?
No. The editor runs entirely in your browser and stores your work in the browser's local storage. Nothing is sent to a server.
Is it safe to paste Flex JSON from other sources?
The editor page is served with a strict content-security policy that blocks any script execution, so pasted content cannot run code. Always review JSON from untrusted sources before sending it, though.