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LINE QR code login from Python

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✅ Verified against LINE Chrome extension 3.7.2 — September 2026 (v2.9.2)

Logging in to LINE from Python is the step every tutorial hand-waves — the official SDK assumes you already have a channel access token, and the old unofficial libraries documented it nowhere. OkLine makes it a one-liner: it renders the login QR as ASCII blocks directly in your terminal, you scan it with the LINE app, confirm a PIN, and you're in. No password, no developer registration, no pasting tokens out of browser devtools.

The fastest path: the CLI

pip install okline
# optional: prettier inline QR
pip install "okline[qr]"

okline login

That's the whole flow: the QR is drawn, you scan it with the LINE app (the QR reader is under the Friends tab), a PIN appears, you confirm it on your phone, your profile prints, and the session — tokens, certificate and E2EE keychain — is saved to ./tokens.json. Every later okline command (and every Python snippet below) reuses that file automatically. Options: okline login --save mysession.json (elsewhere), --wait 240 (longer to scan), --invert (light-background terminal).

From Python

api.qr_login(...) drives the same flow in your own code. Render the QR with print_qr, show the PIN when it comes, and save the session at the end:

from okline import OkLine
from okline.qrterm import print_qr

api = OkLine()
result = api.qr_login(
    on_qr=lambda url: print_qr(url),  # draw the QR — scan it
    on_pin=lambda pin: print("Confirm this PIN on your phone:", pin),
    wait_seconds=180,  # how long to wait for you
)
print("logged in:", bool(result.access_token))

api.save_tokens("tokens.json")  # reuse forever; includes the E2EE keychain

on_qr hands you the login URL — render exactly that (it already carries the mandatory secret parameter, see below). Without the qrcode package installed, print_qr prints the raw URL instead; paste it into any QR generator and scan that.

Once tokens.json exists you never scan again:

from okline import OkLine

api = OkLine.from_tokens_file("tokens.json")  # tokens + E2EE keys restored
print(api.get_profile()["displayName"])
print("E2EE ready:", api.e2ee.is_ready())  # True

What actually happens under the hood

QR login is the LINE Chrome extension's SecondaryQrCodeLogin flow, and OkLine reproduces it step for step:

createSession → createQrCode → (generate a Curve25519 key inside the WASM)
  → show QR  =  callbackUrl + ?secret=<pubkey>&e2eeVersion=1
  → checkQrCodeVerified (you scan) → verifyCertificate / PIN flow
  → checkPinCodeVerified (you confirm the PIN) → qrCodeLoginV2 → tokens

The pieces that matter:

  • The ?secret=…&e2eeVersion=1 query on the QR URL is mandatory. Without it, the LINE app shows "an error occurred" the moment you scan. OkLine generates the Curve25519 keypair inside LINE's real ltsm.wasm and appends it to the URL automatically — so always render the URL your on_qr callback receives, never a createQrCode response you assembled yourself.
  • The PIN step is a device confirmation. First login on a new "device" (i.e. your OkLine session) asks you to confirm a PIN in the LINE app; after that the issued certificate identifies the device.
  • qr_login also unwraps your E2EE (Letter Sealing) keychain during the flow, which is why a save_tokens() right after it produces a session file that can decrypt your sealed chats forever (see E2EE).

Token persistence and refresh

The LoginResult from qr_login carries access_token, refresh_token, certificate and mid. api.save_tokens("tokens.json") writes them (plus the E2EE keychain) to disk; OkLine.from_tokens_file(...) restores everything.

Refresh is automatic: while a refresh_token is set, a credential failure (HTTP 401 or gateway code 119 MUST_REFRESH_V3_TOKEN) transparently renews the access token and replays the request — and when the client was built with from_tokens_file, the refreshed token is written back to the file, so the stored session never goes stale on you. If the refresh token itself is revoked (server kicked you out), you get a LineAuthError and simply re-run okline login.

For long-running daemons you can additionally arm the extension's proactive renewal timer, so the token renews before it expires:

api = OkLine.from_tokens_file("tokens.json", auto_refresh_schedule=True)

Details (retry policy, codes 10201/10202) in authentication.

Certificate reuse: skipping the PIN on later logins

qr_login returns a certificate — proof that LINE has already confirmed this "device". Save it once and pass it on the next fresh login to skip the PIN step (verifyCertificate succeeds for a known device):

result = api.qr_login(on_qr=print_qr, certificate=saved_certificate)

In practice you rarely need this by hand: save_tokens() writes the certificate into your session file and from_tokens_file carries it, so a restored session already behaves like a known device. It matters when you want a fresh login (new tokens) without the PIN dance.

Troubleshooting QR login

  • "Node.js not found" / error code 10005 (REQUEST_INVALID_HMAC) — every request, including login, must be signed with X-Hmac, which OkLine computes by running LINE's real ltsm.wasm through a small Node bridge. Install Node.js 18+ and check node --version in the same shell you run OkLine from.
  • Node installed somewhere unusual? Point OkLine at it with export LINE_NODE=/full/path/to/node (Windows: set LINE_NODE=C:\path\to\node.exe), or OkLine(config=LineConfig(node_path="...")).
  • Phone shows "an error occurred" after scanning — the QR URL was missing its secret parameter, which happens if you rendered a URL other than the one on_qr gave you, or you're on an old version: pip install -U okline.
  • QR unreadable — light background: print_qr(url, invert=True) (or okline login --invert). Garbled blocks on Windows: run chcp 65001 first, or use Windows Terminal / PowerShell 7. Make it bigger with print_qr(url, style="full"). No inline QR at all: pip install "okline[qr]".
  • Need more time to scan? wait_seconds=... (Python) or --wait 240 (CLI) extends the wait for both the scan and the PIN.
  • The PIN never arrives — check the LINE app's notification for a login confirmation request; on some phones you must open LINE manually to see it.

More in troubleshooting.

Where to go next

Next: Getting started · Authentication · LINE Notify replacement · FAQ