Flow overview
This chapter walks through every screen a user sees inside LINE on mobile — from the first tap on your signup link to the replay after the stream ends.
How do people enter the system?
Usually through one of these:
- You put the signup link in your LINE Official Account's welcome message or a message automation flow, and they tap it
- You put a Sign up now button on a sales or landing page pointing at your LIFF signup URL, so both desktop and mobile visitors can go straight into the signup flow (see Sales page button setup)
- You put a LINE add-friend link on an ad landing page (Meta, Google); they add you first, then receive the signup link you send
- A returning user taps a Webinars button in your LINE rich menu
Whichever entry point, they end up on a web page opened by LINE — a LIFF page. To the user it feels like a small signup site that already knows their LINE name and avatar, with no separate registration required.
Question: What is LIFF?
LIFF is LINE's own technology. In plain terms, it puts a web page inside the LINE account permission system. Opened inside the LINE app on a phone it requires no sign-in; opened in a desktop browser it guides the user through authorizing with their LINE account once, after which that browser stays signed in.
The mobile LINE app flow (the most common)
Use case: from tapping your LINE message to watching the replay
- Hsiao-ming receives your LINE message: "Free live session at 8pm on 4/28 — come and sign up!"
- He taps the link, and LINE opens the session detail page in its built-in browser
- The description interests him, so he presses the green Continue to sign up
- He fills in his name and email (the fields you configured in the admin)
- Signup succeeds, and the screen shows "registered" plus an add-to-calendar button
- At 7:00pm and 7:50pm on 4/28, LINE sends two reminders automatically
- Hsiao-ming taps the link in the 7:50 reminder and enters the live room
- He types comments as he watches, and they appear instantly in Live messages in your admin
- The stream ends, and Hsiao-ming can return to the replay any time from My registrations
The desktop browser flow
When someone taps your LIFF signup URL on a computer rather than inside LINE on a phone — from a Sign up now button on a sales page, an email link, or a Google result — they go through an automatic sign-in flow:
- They press the button, and the page immediately redirects to LINE's standard authorization page (showing a QR code to scan with LINE on a phone, or offering desktop LINE sign-in)
- Once signed in, they reach the consent screen (telling them their name and avatar will be shared with your site)
- After consenting, LINE's own hosted "Add friend" interstitial appears with a large Add friend button
- They press it and become a friend of your LINE Official Account
- They're returned to your session detail page — signed in, already a friend, and able to press Continue to sign up
Question: Did I have to build that "Add friend" page myself?
No, it's built into LINE. Set the LIFF endpoint's Add friend option to On (Aggressive) in the LINE Developers Console, and LINE inserts this interstitial automatically whenever a non-friend completes the sign-in flow. Without that setting, it's skipped.
Question: Will people who are already my friends still see the add-friend page?
No. When LINE detects that the user has already added your Official Account, it skips the page and returns them straight to your session list. Returning friends still get a smooth experience.
Note: test with an account that hasn't added you
To see the add-friend button on desktop, test with a LINE account that has never added your Official Account. Otherwise LINE skips the page and you'll conclude the feature isn't working.
The pages a user sees
| Page | URL pattern | When it opens |
|---|---|---|
| Session list | / | When you put an "all sessions" link in your Official Account menu |
| Session detail | /session/:id | The most common — any signup link a user taps |
| Live room | /session/:id/live | The actual viewing screen (YouTube / Meet / pre-recorded) |
| Live room, built-in streaming | /session/:id/live | The attendee-side version when the session uses built-in streaming |
| My registrations | /my | Where a user reviews every session they've signed up for |
How admin actions map to the user side
Everything you do in the admin corresponds to something the user sees:
| Admin action | What the user sees |
|---|---|
| Add a session under Sessions and set it to Published | The session appears in the session list |
| Manually apply a "VIP" tag under Registrations | The user never sees the tag, but it can trigger message automation |
| Build a post-signup sequence under Message automation | The user receives LINE messages at the times you set after signing up |
| Reply under Live messages | Your reply appears immediately in the live room chat |
| Attach a message script to a video in the media library | The user receives LINE messages at the specified seconds while watching a pre-recorded video |
Question: Do users need to add me as a friend first?
It's strongly recommended. Someone who hasn't added you can still sign up as a guest inside the LINE app on mobile, but they will:
- Receive no automated LINE messages at all (reminders, follow-ups, automation flows)
- Not have their past signups filled in automatically on the My registrations page
Users arriving through a desktop browser go through the automatic sign-in and add-friend flow by default (provided the LIFF endpoint's Add friend option is set to Aggressive), with nothing extra for you to design.
Question: Can one phone be signed in to several LINE accounts?
No. A LIFF page follows whichever account the LINE app is currently using, so one phone means one person. To sign a friend or family member up, do it on their own phone.